| Observation date | Time submitted | Observation location | Reporter | General Info | Wx Observation | Snow Observation | Avalanche Observation | |
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| 2025-03-14 | 23:03:00 | Marias Pass - Elkcalf Mtn | Clark | • Went to the Pike Creek SNOTEL SE of Marias Pass, then up the north slopes of Elkcalf Mountain to the summit. • Descended the same route. | • Mostly cloudy in the AM, transitioning to mostly sunny in the afternoon. Scattered snow showers with brief periods up to S2 intensity. 1” of accumulation today, but only in shaded terrain above 6000’. • Daytime highs reached to low-30s °F at Marias Pass and the low-20s °F up around 7000’. | • Recent snow on top of a supportable melt-freeze crust made for fast travel. • No signs of instability observed. • 4” of recent snow at 5200”, increasing to about 6” at 6000’, and then to 8-9” above 7000’. • The new snow was right side up with lower density layers on top of a heavier layer from earlier in the week. • The crust under the recent snow was near 8” thick at 6000’ and supportable in boots. At our high point at ~7600’ the crust was still present and supportable in skis. • Moderate SW winds were actively loading lee slopes above 6000’ in the morning. Winds died down in late afternoon and wind loading mostly ceased. | • No avalanche activity observed. | |
| 2025-03-05 | 17:40:00 | Lower Path 1163 | Clark | • Up into the lower reaches of Path 1163. • Objective was to investigate the runout of the previously reported very large avalanche that ran sometime early on Feb. 24th. | • Mostly cloudy in the AM, transitioning to partly sunny in the afternoon, no precipitation. • Winds were light from the SW on the Canyon floor with light to moderate SW winds above 6000’. • Daytime highs reached to low-40s °F on the Canyon floor this afternoon. Weather stations at 6400’ topped out in the mid to high-20s °F. | • 1” of new snow on top of a melt freeze crust which was sometimes supportable on skis, sometimes not. • Many sun-exposed slopes below 5000’ of disconnected patches of remaining snow with a lot of bare ground. • We could see some minor wind loading occurring above 6500’ due to SW winds. | • This was an impressive avalanche with debris reaching 4500’ elevation which is about 850’ lineal feet from the rail (~85% distance to the rail). • Estimated the debris pile to be several hundred feet long and up to 20’ deep or more in some places. • This avalanche initiated about 2500’ above as a slab and then entrained a substantial amount of wet snow as it moved downhill, HS-N-R3-D3-O. • There were several chunks of broken trees in the debris, some reaching 8-10” in diameter. |
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| 2025-02-27 | 22:36:00 | Shed 8 | Clark | • Up the Shed 7/8 ridge into the upper starting zone of Shed 8. Continued across the path to view the upper reaches of Shed 9. • Descended Shed 7 West. • Objectives were to investigate the slab avalanche in Shed 8 that ran on Feb. 24th and to look for additional avalanche activity in Shed 7 West and Shed 9. | • Sunny, breezy, and warm with no precipitation. • Winds were light with moderate gusts from the SW on the Canyon floor with moderate to strong SW winds above 6000’. • We broke 50 °F on the Canyon floor this afternoon. Weather stations at 6400’ reached 40 °F. | • Below 5000’ the snowpack is entirely wet with the Feb. snowfall resting on very weak facets beneath. If your skis broke through the “trap door” into the facets beneath, ski penetration was almost to the ground (1-2’). • From 5000-6000’ travel is better as the crust formed on Feb 25 is supportable with about 10-20 cm of recent snow on top. This crust thins out by 6200’. We suspect this was likely the height of the freezing level during the Feb 23-24 AR event. • The snowpack on the Canyon floor is melting fast. | • Observed avalanches running today were limited to D1 wet loose on sunny aspects that involved the top 15 cm of recent snow. One pesky slide knocked my ski down the Shed 8 path for a short distance while I was trying to conduct the crown profile. • Confirmed that there were no slab avalanches in Shed 9 or Shed 7 during the Feb 23/24 cycle. • Confirmed that the previously reported D2 avalanche in Curly on the N face of the Devils Hump was a slab with a crown visible in the start zone near 6000’. • Some more details on the previously reported avalanche in Shed 8, HS-N-R2-D2-O: o Hard slab that failed within a layer of older wind slabs that likely formed earlier in the month. The late-Jan. facets were another 30 cm below the bed surface. o Crown thickness was about 1 m and located at 6200’ on a south aspect and a 38° slope. Crown width was difficult to determine, estimated at 50-70 m. o About 400’ vertical feet down, the debris cut loose a 2nd slab, about 50-70 cm thick at 5800’ that failed on the late-Jan facets. o The debris terminus was estimated at 5000’ elevation, or about 2/3rds distance to the rail. |
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| 2025-02-23 | 20:53:00 | JFS Canyon | Clark | • Road observations from Highway 2. | • Rain began around midnight last night and became heavier by mid-day. Rainfall totals on the Canyon floor have reached about 1.00”. • The rain/snow line was at about 5000’ at 1000 hrs and then rose to near 6000’ by sundown. • Calm or light winds from the SW on the Canyon floor with moderate SW winds above 6000’. • Daytime high temperatures reached the high-30s °F on the Canyon floor. Weather stations at 6400’ reached 32 °F. | • Widespread wet loose avalanche activity today with sizes ranging from destructive size 1-2 (D1-2). • Freezing levels climbed throughout the day and the avalanche activity crept upwards in elevation while trending towards larger magnitude events. • Visibility was limited, but crowns of recent slab avalanches were observed on the north face of Devils Hump and on the south face Little Dog Mtn and possibly on Nyack Mtn in the Cascadilla basin. • A few notable avalanches include: o Multiple wet loose slides in Shed 12, up to D2 in size with debris on, or near the shed roof. o D2 wet loose in Path 1163 with debris terminating well above the rail. o D.15 wet loose slides in Blue Rock East above Hwy 2 with small amounts of debris reaching the shoulder of the eastbound lane. o D2 wet loose in Burnout with debris terminating on top of the snowshed wall and in the slide fence. Debris in the fence was about 4-6’ deep and 30’ wide. o D2 in Larrys that appeared to have initiated as a slab up near 5900’ but then entrained a lot of wet snow on the way down. Debris ran about 1500’ and terminated about 400’ vertical feet above the highway. |
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| 2025-02-21 | 18:21:00 | Snowslip Mtn- Burnout to Shed 7 | Clark | • Ascended the east ridge of Snowslip Mtn. above the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths. • Descended the same route. | • Broken skies becoming mostly cloudy by the afternoon. Occasional light snow above 6000’ with light rain on the Canyon floor. • A windy day with moderate to light winds from the SW on the Canyon floor with strong SW winds above 5500’. • Also a warm day with daytime high temperatures reaching the low-40s °F on the Canyon floor. Above 6000’ temperatures range from the mid-20s to 30 °F. | • Snowpack surface was moist up to about 6000’ which limited wind transport. • Moderate to heavy wind loading above 6000’ where the snowpack surface was still dry. • Found a poor structure snowpack with 1-3’ of snow from February that’s stiffening into a more cohesive slab over the late-Jan. weak layer of facets. • Dug a hasty pit just above the Burnout path at 5200’ on an east aspect. Snow depth was 37” with a 12” slab on top of the late-Jan. facets. ECTN22 and CT21/Q2 on the slab/facet interface. • Dug a 2nd hasty pit in the Shed 4D path at 5300’ on an easterly aspect. Same snow depth and structure as we found in Burnout. ECTN13 on tp of the late-Jan. facets, then ECTP24 near the ground on an old layer of facets. • Third hasty pit in the Shed 5 path at 6000’ on a SE aspect. Snow depth was 67” with 24” of wind slab on top of late-Jan. weak layer. No fractures on this interface. But ECTP23 about 10” down, which was the most recent wind slab. | • A few very small (D1) wet loose sluffs on steep slopes above the river and highway. • D1 WL in Umbrella Fence obs. in afternoon. Debris 1-2’ deep, 3-4’ wide on Main 1. • No other avalanches observed. |
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| 2025-02-19 | 22:48:00 | Devils Hump | Clark | • Ascended northerly slopes up onto the uppermost reaches of Devils Hump Mtn. • Descended the same route. | • Mostly clear skies provided excellent views of the avalanche terrain above the Railway and Hwy 2 (photo). • Calm, or light winds from the SW. • No precipitation • Cold, sub-zero °F air temperatures on the Canyon floor in the morning, warming to the 20s °F by the afternoon. | • Other than the D1 sluffs, no other signs of instability observed. • Most of the tour was spent in terrain sheltered from the wind. But we found wind slabs unreactive to ski cuts up on the ridge crests above 7000’. • 1-3’ of new and recent snow has settled on top of the late-Jan facets. In terrain sheltered from the wind this new snow has not formed a cohesive slab. • Below 5500’ the snowpack was composed of soft facets below the most recent snow and made for slow uphill travel. Ski penetration was typically 12-20+” and almost to the ground. • Minimal wind loading above 7000’. | • Several D1 loose dry avalanches on steep, rocky terrain above 6000’ (photo). • No slab avalanches observed. |
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| 2025-02-13 | 22:31:00 | Shed 10.7 & Path 1163 | Steiner | • Objectives were to conduct a welfare check on the Shed 11 Wx Station and observe Program Area field conditions related to avalanche, snowpack, and weather. • Ascended the ridge between Shed 10.7 & Shed 11 to the Shed 11 Wx Station, then continued up the SW ridge of Running Rabbit Mountain to the starting zone of Path 1163. | • Mostly clear sky • Calm winds. • No precipitation • Air temperatures: o 1000 @ Canyon Floor: -12°F o 1500 @ Upper Elevations:15°F | • NUMEROUS audible collapses at low (canyon floor elevations) and upper elevations- Up to ~7000’. • Snow conditions throughout the day varied between hard scoured snow surface, wind slab, and unconsolidated surface snow (facets) made for slow uphill travel. • Ski cuts triggered minor wind slabs (2-4” thick, 3-8’ wide) on small test slopes (photo). • Dug a test pit at ~7200’ elevation on a southeasterly aspect in the Starting Zone of Path 1163. Snow depth was 37” with a 12” thick, 1F hard slab resting on top of the late-Jan. facets. ECTN18 on the facets. • Dug another pit in the I-Beam avalanche path on a westerly aspect, at 7300’ elevation. ECTX 2x in this pit. See pit profile for details. | • No recent avalanche activity observed. | |
| 2025-02-07 | 21:38:00 | JFS Canyon, Burnout to Shed 7 E | Clark | • Ascended the east ridge of Snowslip Mtn and checked on the Burnout, Shed 4D, Shed 5, and Shed 7 East avalanche paths above the rail. • Road obs from Hwy 2. • Objectives were to look for recent avalanche activity and assess the snowpack structure and stability following the recent storm. | • Cold, single digit °F temperatures with light NE winds up at the ridge top. • Mostly cloudy in the morning becoming mostly clear by late afternoon with sunshine. No precipitation. | • Snow depths from the Jan. 31 to Feb. 5 storms ranged from 8-10” on the Canyon floor and 12-20+” above 6000’. • Wind loading earlier this week was heavy. Dunes 2-4+ feet thick have formed up on the ridgelines and wind slabs are found at all elevations. • Dug a hasty pit just above the Burnout avalanche path at 5200’ on an east aspect. Found poor structure developing with the late-Jan. facets now buried under 10-12” of recent snow. New snow was not cohesive enough yet and propagation wasn’t there. See pit profile below. • Dug another hasty pit in Shed 7 West at 6600’ on a SE aspect. The late-Jan. facets are buried under a 20” slab. But again, no propagation (ECTN15 on the late-Jan. facets) as the slab was not cohesive enough at this time. • We had one audible collapse near the top of the snowshed down at 4500’. | • Found another avalanche today that we missed earlier this week due to poor visibility in Path 1163. Looked like a wind slab that failed at the very top of the path and then debris ran to the bench at 4800’ terminating above the rail. Estimated it ran on Feb. 5th. Crown estimated at 100 m wide and about 100 cm thick at the max end. SS-N-R2-D2-I. • No other avalanches observed. |
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| 2025-01-31 | 21:10:00 | Snowslip Mtn- Burnout to Shed 7 | Clark | • Ascended the east ridge of Snowslip Mtn and checked on the Burnout, Shed 4D, Shed 5, and Shed 7 East avalanche paths above the rail. • NPS Winter Wilderness Ranger Jackson George joined me today and brought his snow scope tool for measuring hardness profiles in the snowpack. • Objectives were to assess the snowpack structure in this area. | • The day began with broken skies and warming temperatures (40°F on the Canyon floor at noon). • Around 1300 skies became overcast, temperatures dropped, westerly winds picked up, and light snowfall began. | • In the Burnout path a 2-3 cm crust has formed on the snowpack’s surface from the previous few days. Beneath this crust the snowpack consists of F to 4F-hard facets. (See hardness profile below). The top 20 cm of the snowpack was moist. • Above 5500’ this surface crust dissipated on easterly aspects. But then reappeared once we wrapped around onto a more southerly aspect in Shed 7 East at 6300’. (See hardness profile below). • Westerly winds began to pick up in the afternoon and began transporting snow. 2-3” thick wind slabs had formed by 1500 hours but were unreactive. | • No avalanche activity observed. | |
| 2025-01-22 | 18:00:00 | Second Slide to Shed 10 | Clark | • Ascended the Second Slide avalanche path and then continued up into the upper reaches of Shed 10. • Objectives were to assess the snowpack structure and stability in this area including a full profile in the Second Slide path. | • Overcast skies in the morning changing to mostly clear by sundown. • Winds were calm on the Canyon floor and sometimes even so up on the ridge crests. Occasional light gusts from the SW above 5000’ • Daytime high air temperatures reached the high-20s °F on the Canyon floor and the teens °F above 6000’ elevation. | • The surface of the snowpack has been faceting and is especially weak in locations where there is no surface crust. • There are a variety of surface crusts from the wind and sun over the past week in the upper snowpack. These all have weak facet layers around them as well. We were able to initiate some shooting cracks that ran 10-20’ in these layers. Not much of concern now but may become so if the weak layer(s) are preserved and a slab builds on top. • Dug a snow pit in the Second Slide avalanche path at 5500’ elevation on a south aspect, 38° slope. Snow depth was 31” and the upper half of the snowpack is basically a stack of facets and crusts. Extended Column Test yielded propagation under last week’s sun crust. This layer is only 2” down now. See pit profile for details. | • Several old wet loose avalanches in Shed 10 that ran last week on Jan. 15th. Most were D1-1.5 in size but the largest was D2 size and ran in Shed 10 W Feeder. | |
| 2025-01-13 | 23:59:00 | Burnout to Shed 4D | Steiner | • Ascended and descended east ridge of Snowslip Mountain. • Objectives were to observe avalanche, snowpack, and weather field conditions. | • Overcast • Light SW winds. • S-1 snow showers • Air temperatures below freezing at all elevations. | • Examined Snowpack structure and conducted stability tests @ 5902’ a.s.l in the starting zone of Shed 4D. • Please refer to attached Snow Pilot profile for snow observation details. | • No recent avalanche activity observed. • No obvious signs of instability. • Previous windloading on mid-elevation easterly aspects (Refer to attached photo) |
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| 2025-01-04 | 18:05:00 | JFS Canyon, Burnout to Shed 7 | Clark | • Road observations from Hwy. 2 and then a ski tour up into the Burnout, Shed 5, and Shed 7 terrain. • Objectives were to look for recent avalanche activity, asses new snowfall and wind-loading, and work on the weather stations. | • Overcast skies with light snowfall in the morning which ended around mid-day with a trace of accumulation. • Winds subsided substantially in the night and were calm on the Canyon floor and light from the SW above 6000’. • Air temperatures in the morning were inverted with the single digits °F on the Canyon floor and low-20s around 6500’. The afternoon the Arctic air had mixed out of the Canyon, and it warmed to the mid-20s °F at all elevations. | • Fresh wind slabs from last night’s storm were present at all elevations, but sheltered, treed terrain still held plenty of soft snow. Other than the mini slab mentioned above, for the most part these new slabs were unreactive to ski cuts. • No shooting cracks or audible collapses. • Total snowfall for the Jan. 3rd/4th storm was about 4-5” with 0.20-0.30” of water on the Canyon floor. • Dug a snow pit in the Burnout avalanche path at 5200’ elevation on an E aspect, 25° slope. Snow depth was 30”. Found a right-side up snowpack - generally denser layering with depth. 20” soft slab (F to 4F hard) resting on top of melt-freeze crust with no facets at the interface. Not propagation with an Extended Column Test. | • 1 recent avalanche in the Infinity path above the rail, south aspect. I could only see debris and not the crown. Destructive size 2 (D2) and debris ran ½ path terminating well above the grade. Judging by debris and no visible crown, I think this was likely a wind slab that failed on the pre-storm interface and not a deeper weak layer. SS-N-D2-I. • We also ski cut a very small (6’ wide, 12” thick) wind slab in Shed 5 at 5100’ on an east aspect, SS-ASc-D1-I |
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| 2024-12-30 | 19:22:00 | Shed 11 and Shed 10.7 | Clark | • Ascended the Shed 10.7 ridge to the Shed 11 weather station at 6400’ elevation. Descended the same route. • Objectives were to look for recent avalanche activity, asses new snowfall and wind-loading, work on the weather station, and examine the snowpack structure and stability in the Shed 11 avalanche path. | • Overcast skies, calm or occasional light westerly winds above 6000’ and light easterly winds below that elevation. • Snowfall was intermittent with 20–30-minute bursts of S2-S5 rates alternating with longer, 1–2-hour periods of S-1 snowfall or no precipitation at all. • Total accumulation over the day was another 3-4”. • Daytime high air temperatures reached the high-20s °F on the Canyon floor and the low-20s °F at 6400’. | • Overnight snowfall was about 6” on the Canyon floor and 8” at 6400’. • Total snowfall since Dec. 26th is about 15” on the Canyon floor and 18” above 6000’. • Winds were and had been calm and there was no recent wind loading. • No shooting cracks or audible collapses. • Overall, the new snow lacks in cohesion and has not formed a threatening slab yet. Observed some very minor sluffing on steep (40°+) terrain. • Dug a snow pit in the Shed 11 path at 6400’ elevation on a SE aspect, 30° slope. Snow depth was 45”. Found a right-side up snowpack - generally denser layering with depth. o Did not find a reactive layer of facets on top of the early-Dec. crust like we did in Shed 7 West on Dec. 27th. See details in pit profile. | • No avalanche activity observed in the terrain I travelled through nor in distant terrain I could view. | |
| 2024-12-27 | 22:02:00 | Shed 7 | Clark | • Ascended the Shed 6/7 ridge to the Shed 7 weather station then up to a high point at 6600’ in the Shed 7 West avalanche path. • Descended Shed 7 West. • Objectives were to look for recent avalanche activity, asses new snowfall and wind-loading, and examine the snowpack structure and stability in Shed 7 West. | • Broken skies, calm to light westerly winds, no precipitation. • Daytime high air temperatures reached the mid-30s °F on the Canyon floor and the mid-20s °F around 6000’. | • Total snowfall yesterday was about 3”. Precipitation transitioned to rain on the Canyon floor in the afternoon. Total precipitation was about 0.20” water. • Strong westerly winds last night scoured the snowpack down to the uppermost crust in exposed locations. • Shallow (4-5” thick) new wind slabs had formed on leeward slopes. Ski cuts only initiated minor shooting cracks, 2-4’ long in some instances. • No audible collapses. • Dug a snow pit in the Shed 7 West path at 6600’ elevation on an ENE aspect, 27° slope. Snow depth was 35”. Stability tests provided mixed results but we found a layer that was somewhat concerning in some rounding facets resting on top of a melt-freeze crust located about 16” deep. See details in pit profile. | • No recent avalanche activity observed save for some minor cornice fall save for some minor cornice fall in Shed 7 West. • There was some very old debris (D1.5 size) that ran about 1000’ down Shed 7 West from the top of the path. Debris terminated well above the rail grade. No crown was visible, and we suspect this may have been a dry loose, possibly triggered by a cornice break. |
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| 2024-12-19 | 23:00:00 | Grizzly Gulch | Clark | • Ascended Grizzly Gulch to the east face of Running Rabbit and up to the summit. • Objectives were to look for recent avalanche activity, asses new snowfall and wind-loading. | • Clear in the morning, increasing clouds, and mostly cloudy by sunset. • Calm winds in the gulch, light to moderate westerly winds above 7000’. • No precipitation. • Daytime high air temperatures reached the high-30s °F on the Canyon floor and the high-20s °F above 6000’. | • Yesterday it rained up to about 5500-6000’ and then cooled off overnight forming a rain crust on the snowpack surface. This crust disappeared at about 6000’ elevation. • Snowfall totals from the Dec. 18th storm above 6000’ were about 6-10” with easterly aspects favored. Westerly aspects above 5500’ were scoured heavily by the strong westerly winds. • Dug a hasty pit at 7200, on an easterly aspect. Had fracture, but no propagation with an Extended Column Test on the Dec. 18 storm interface (see pit profile below). • Light to moderate westerly winds were transporting very little snow as the snowpack surface was either a crust or more stiff powder and/or wind crust. | • Observed 2 destructive-size 2 (D2) soft slabs, and 4 more D1s that failed during yesterday’s storm. • These occurred on a steep easterly aspect at 6700’ and debris ran about 1000’ vertical feet. SS-N-R2-D1&2-I • These avalanches consisted of the newest storm snow and did not fail on, or step down to an older persistent weak layer. • Also observed one D2 size soft slab in Skiumah Creek from the highway. |
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| 2024-12-12 | 22:00:00 | Shed 7 East | Steiner | • Ascended the Shed 6/7 ridge. • Objectives were to work on the Shed 7 East Weather Station, observe snowpack structure, and observe weather conditions. | • Clear to partly cloudy skies. • Calm winds. • No precipitation. • Air temperatures below freezing at all elevations. | • No audible failures, shooting cracks and/or collapsing. • In general, found more stable snow on sunny aspects. • The Dec. 7th/8th storm left about 6” of new snow above 6000’. • Examined structure and conducted Extended Column Tests on two different aspects at similar elevations: o Test Pit 1: NE aspect, 30° slope, 6382’ a.s.l., 39” snow depth/100 cm. ECTN15@ 70cm ECTP 20@ 35cm on 1mm facets on top of the early Nov melt-freeze crust. 1F hardness slab above. 2nd ECT: ECTN13@70, ECTN29@35 o Test Pit 2: SE aspect, 33° slope, 6266’ a.s.l. Snow depth 33”/85 cm ECTX, ECTX, CT25@25cm on facets on top of early Nov. melt-freeze crust. • No occurring or recent wind loading. | • No recent avalanche activity observed. • No evidence of recent cornice growth or failure |
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| 2024-11-26 | 23:11:00 | Burnout to Shed 7 W | Clark | • Climbed the east ridge to the Shed 7 weather station at 6400’ elevation. Then continued above Shed 7 W to the Snowslip weather station. • Objectives were to clear rime ice off the weather stations and get the wind sensors operational again. • Also, we went to look for any recent avalanche activity and observe the developing snowpack. | • Broken skies with only occasional very light snowfall. • Winds were calm or light from the SW with occasional moderate gusts above 6000’. • Daytime highs hovered around the freezing point on the Canyon floor and reached the mid-teens °F up around 6400’ elevation. | • Snow depths on the Canyon floor are about 10-14”. Depths at 5000’ increased to about 20”, and above 6000’ ranged from 2-4’. • A quick test pit in the Burnout avalanche path revealed a right side up snowpack without any notable weak layers (pit profile below). The basal layers consisted of moist grains capped by a thin, fragile melt-freeze crust. • Light westerly winds were transporting minimal amounts of snow near ridge crests (photo). The cornice above Shed 7 West is beginning to grow. • No other signs of instability observed. | • No avalanche activity observed save for a few small chunks of cornice breaking off in Shed 7 West. • Visibility of distant terrain was pretty good and we could not view any crowns or debris. |
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| 2024-11-19 | 22:40:00 | Shed 11 to I Beam | Clark | • Climbed the Shed 11/10.7 ridge to the Shed 11 weather station at 6400’ elevation. Then continued up to the top of Path 1163, and then made a trip to the west face of Running Rabbit into I Beam. • Objectives were to check the snow depth readings reported by the Shed 11 weather station and to observe the developing snowpack. | • Obscured skies above 6000’ with on/off light snowfall all day. 1-2” accumulation above 6000’. • Winds were remarkably calm with occasional very light puffs from the west. No blowing and drifting snow. • Daytime highs reached the high-20s °F on the Canyon floor and the high teens °F up around 7000’ elevation. | • 2-3” snow depths on the Canyon floor, 4-8” at 5500’ elevation, 12-14” at the weather station at 6400’ (weather station snow depth is accurate). • Snow depths increased quickly above 6500’. On average there was about 2-3’ of snow above 7000’ elevation. • Dug a test pit in the uppermost reaches of Path 1163 at 7200’ elevation, east aspect, 34° slope. Snow depth was 32”. There was a thin layer of facets above a crust near the base. But no propagation in an Extended Column Test. (pit profile below) • Dug a second pit on the other side of the ridge at 7300’ on a west aspect in the I Beam avalanche path. Snow depth here was 35” and I found a layer of buried surface hoar 24” down that was reactive. ECTP 25 in Extended Column Test and a Propagation Saw test on this layer yielded PST 45/100 END down 60 cm. • No other signs of instability observed. | • No avalanche activity observed in the terrain I traveled through. • Visibility of surrounding terrain was very limited by fog and so I could not check out distant slopes. |
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| 2024-03-21 | 22:57:00 | Shields Creek | Clark | • Ski tour up the SE ridge of Snowslip Mtn above the Burnout and Shed 4D avalanche paths to about 6100’. Then went north into Shields Ck. basin to the debris terminus of last week’s large avalanche. • Objectives included: check out the new surface crust, new snowfall totals, and wind-loading. • Also, went to investigate the previously reported large avalanche in the upper Shields Ck. basin that ran on Fri. Mar.15th. | • Mostly overcast skies and less precipitation than forecasted. About 2” of new snow above 6000’ by the end of the day and no accumulation on the Canyon floor as precip. transitioned to rain. • Calm to light winds from the west for most of the day, then clocking to the east and increasing in speed around 1500 hrs. • Air temperatures reached the high-30s °F on the Canyon floor but then fell rapidly around 1500 as cold air pushed over the Divide and flowed down the Canyon. | • No signs of instability observed today but we stayed in terrain sheltered from the wind. • Above us on the ridge crests moderate to strong SW winds were moving substantial amounts of snow and likely forming fresh wind slabs throughout the day. • 1” of snowfall overnight above 6000’ with but a trace on the Canyon floor. • Under the fresh snow we have a new melt-freeze crust that is several inches thick below 5500’ on all aspects. This made for fast travel today…where there was snow. • Above 6000’ on northerly aspects this new crust was breakable on skis and only about 1” thick. The snowpack was moist for about an inch or two below the crust and then quickly transitioned to dry below this. | • No recent avalanche activity observed. • Some additional information on the Shields Creek avalanche: o Occurred on a SE aspect, top of crown was at about 6800’ and the debris terminated at 5500’ for a vertical fall of 1300’ (photo). o A destructive size 3 of 5 (D3) hard slab with an estimated crown height of 2-4’ and crown width of 500-600’. o Debris had gouged to the ground in the lower start zone and track and broke a few trees. |
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| 2024-03-13 | 22:12:00 | Summit/Marias Pass - Elkcalf Mtn | Clark | • Ski tour from Summit/Marias Pass to the summit of Elkcalf Mtn. Passed by the Pike Creek SNOTEL. • Objectives were to check on the Pike Creek SNOTEL, look for any recent avalanche activity, and check out the recent snowfall and wind loading in this area. • Pike Creek SNOTEL looked to be in good shape and the snow depth readings here are accurate. | • Partly cloudy with on again/off again sunshine. No precipitation. • Light winds from the SW. • Wind loading today was minimal in this area. • Daytime high temperatures reached the mid-30s °F at Summit/Marias Pass. | • Other than the avalanche, no other signs of instability observed. • Other recent wind slabs were unreactive to ski cuts. • A new surface sun crust was beginning to form below 6000’ on previously sun-exposed slopes by late afternoon as these passed into the shade (easterly aspects). • Slopes above 6000’ and sheltered from the wind had about 6-8” of recent settled powder. • Impressive wind re-distribution of snow in this area with entire mountainsides scoured to the ground on more westerly aspects alongside with wind loaded gullies that had drifts pushing 20+ feet thick. | • One wind slab that was likely triggered by a cornice fall on a NE aspect at 6800’ SS-N-D2-R2-I. Crown looked about 10” thick and ~150’ wide and probably ran sometime in the past 48 hours. | |
| 2024-03-07 | 21:43:00 | Sheds 5, 7, 9 | Clark | • Ski tour up the Shed 6/7 ridge, continued up above Shed 7 W, over Pt. 6876’ and on to the Snowslip weather station and the uppermost reaches of Shed 9. Descended the skin track to Shed 5, then down this path. • Objectives were to see if any avalanches occurred in upper Shed 9 during last week’s cycle and to examine snowpack structure and stability in this path. Also wanted to check on the weather stations and repeat stability tests in the same pit as last week in Shed 7 West. | • Mostly clear with plenty of sunshine. • Light winds from the SW with occasional moderate to strong gusts. • Wind loading today was minimal in this area. • Daytime high temperatures reached the mid-teens °F at 7000’, the low-20s °F around 6000’, and the mid-30s °F on the Canyon floor. | • Wind slabs were widespread above 5500’ but mostly unreactive to ski cuts. A few cuts produced 1-2’ fractures. • A new surface sun crust was beginning to form below 6000’ on previously sun-exposed slopes by late afternoon as these passed into the shade (easterly aspects). • Dug a snow pit in the upper reaches of Shed 9 at 6740’ elevation, SE aspect, 27° slope. o Total snow depth here was 51” with a poor structure snowpack, and unstable results in two stability tests. o ECTP x2 with moderate force on a layer of facets on top of the Feb. 6th crust (see pit profile). • Repeated an Extended Column Test in Shed 7 West at the same location as last Thursday (Feb. 29th). o Snow depth here was 71” with the Feb. 3rd crust now buried about 3 feet down. Structure was like that in Shed 9 with multiple facet/crust combo layers beginning about 20” down. o A few ECTNs in the upper 20”, but no fractures on the facet/crust combo layers deeper in the snowpack. | • No recent avalanches observed. • No avalanches occurred in Shed 9 during last week’s cycle. • The crowns from the previously reported events in Shed 7, Path 1163, and the north face of Devils Hump were still partially visible. |
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| 2024-02-29 | 23:25:00 | JFS Canyon and Shed 7 West | Clark | • Observations from Hwy 2 and a ski tour up the SE ridge of Snowslip Mountain to the upper elevation starting zones in the Shed 7 avalanche path. • Objectives were to document the recent avalanche activity, assess recent snowfall totals and wind-loading and investigate the snowpack structure near a recent hard slab avalanche in Shed 7 West. | • Mostly overcast with occasional broken skies in the afternoon. • No precipitation all day until about sunrise when a rain/snow mix began on the Canyon floor. • Very windy, sustained moderate winds from the SW with strong to extreme gusts. • Wind loading was intense with several hundred-foot-long plumes of snow off the ridge crests above 6000’ at times. • Freezing levels climbed throughout the day reaching just above 6000’ by late afternoon. | • The most recent melt-freeze crust from Monday (Feb. 26) on the Canyon floor thinned out and disappeared around 4800’. This now has about 2-4” of wet snow on top. • About a foot of recent snow above 5500’ with heavy wind loading from the SW winds. • Fresh wind slabs 1-4+ feet thick were observed above 6000’, primarily on N thru E aspects. Limited cracking from ski cuts in these slabs. • Observed one audible collapse on the SE ridge about 6200’ elevation. • We dug a snow pit within 50 yards of the recent hard slab crown in Shed 7 West (pit profile). We could not safely access the crown today. o Total snow depth was about 69” with the early Feb. facet layer buried about 35” down. o Stability tests results were variable with a mix of stable and unstable results. o We suspect the failure layer of the nearby avalanche was the layer of facets above the Feb. 3rd crust. | • Several large hard slab avalanches observed today including. These all likely ran last night: o Path 1163, HS-N-R3-D2.5-O, SE aspect, top of crown ~7000’ with debris running to about 4600’ elevation, or about ¾ distance to the grade (photo). o Shed 7 West, HS-N-R2-D2.5-O, SE aspect, top of crown ~6500’ with debris running to about 5200’, or about ½ distance to the grade (photo). o SE face of Snowshed Mtn, HS-R2-D2-O, limited views from Hwy, size estimated, could’ve been larger. o North face of Mt Furlong (Broken Bridge path that threatens Hwy 2), HS-N-R2-D2.5-O, at least 2 separate avalanches starting at about 7000’ elevation. Debris terminus unknown, but well above the highway. o North face of Devils Hump (west peak, Pt. 7667’), HS-N-R3-D3-O. Largest avalanche observed, crown estimated at least 1000’ wide. • For many events it appeared that a cornice fall, and/or a wind slab near the ridge crest above may have triggered these larger avalanches. We suspect the failure layer to be the facets above the Feb. 3rd crust. |
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| 2024-02-21 | 19:00:00 | Tunnel Ridge | Clark | • Snowmachine and ski tour up to the weather station (wind site) with Cam Johnson from the Flathead Avalanche Center. • Objectives were to investigate the snowpack structure and stability in this area, and perform a welfare check on the Tunnel Ridge weather station. | • Scattered clouds and no precipitation. • Daytime high air temperatures reached freezing at 6800’ elevation and the low-40s °F on the Canyon floor. | • Snowpit tests on both north and south aspects revealed unstable results. Both snow pits failed on facets and surface hoar above the early February crust. • The upper snowpack structure is not inspiring. Although facets are showing signs of rounding, extended column tests had some energy when they propagated. • We dug two snow pits at roughly 6800 feet. o South aspect: ECTP22 down 50 cm. This failed on a layer of near-surface facets and surface hoar just above the early December Crust. o Northeast Aspect: ECTP15 down ~60cm (pit profile). | • We observed two wet debris piles on southerly-facing aspects. I suspect these occurred on Monday, February 19th. No crowns were visible in the upper start zones. These were likely Wet Loose. • Observed one natural slab avalanche on a ramp off Mt. Grant. The crown appeared to be at roughly 6400 feet on a northeast aspect. Flat light made it difficult to get any quality photos. |
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| 2024-02-13 | 22:56:00 | Shed 7 to Shed 5 | Clark | • Hiking and ski tour on Snowslip Mtn to the upper starting zones in Shed 7 and Shed 5. • Objectives were to check out the new snowfall totals and extent of recent wind loading, investigate the snowpack structure in this area, and perform a welfare check on the Shed 7 weather station. | • Overcast skies and intermittent very light snowfall all day. Total daytime accumulations were about 1” on the Canyon floor and 2-3” above 6000’. • The well-advertised Arctic airmass pushed over first thing this morning. By sunset temperatures had only dropped into the low-teens °F above 6000’ elevation and the low-20s °F on the Canyon floor. | • Snowpack remains quite thin below 5500’ elevation. Snowfall from the past five days totaled about 6-8” with 0.40-0.50” water equivalent. • Above 5500’, snow depths increase substantially with about 10-18” of soft powder snow resting on top of the truly remarkable Feb. 3rd crust which is over a foot thick in places. • On sunny aspects there is a thin sun crust from Feb. 6th which is now buried about 10-16” down from the surface. • There is a layer of facets located between the Feb. 3rd and Feb. 6th crusts that we’ll need to watch as the snowpack continues to develop. • No signs of instability observed. • Winds were light from the east to NE today with minimal wind loading. • Dug a snow pit in the Shed 7 West path at 6650’, SE aspect, 30° slope. Snow depth here was 51”. A layer of facets exists between the Feb. 3rd and Feb. 6th crusts (pit profile). A steep temperature gradient was present in the upper half of the snowpack. Extended Column Test yielded ECTN 21 just under the Feb 6th crust and then CT 10 Q2 just above it. | • No avalanche activity observed. | |
| 2024-02-06 | 22:04:00 | Shed 11 to Grizzly Gulch | Clark | • Hiking and ski tour on the south face of Running Rabbit on the Shed 11/10.7 ridge to the weather station. Then upward over the south summit of Running Rabbit above Path 1163, across uppermost Shed 10, and out Grizzly Gulch. • Objectives included investigate the snowpack structure in this area including the depth of new snow and the thickness and distribution of the recent February crust. Also perform a welfare check on the Shed 11 weather station. | • Scattered clouds with no precipitation and pretty much calm winds at all elevations. • Daytime high air temperatures reached 40°F on the Canyon floor, the mid-30s °F at 6400’, and right at the freezing mark at 7000’. | • Snowpack is thin and patchy or non-existent on sunny slopes below 5000’ elevation. • Recent snowfall totals from the past few days ranged from 2-3” on the Canyon floor and 6-8” above 6000’. • This recent snow was cooked today on sunny aspects and a new surface sun crust began to form as this terrain became shaded later in the day. • Noted a few recently formed 6-12” thick wind slabs above 7000’, mostly on easterly aspects. These were unreactive to ski cuts. • Underneath the recent snow we have a thick new crust due to last week’s warmup and the subsequent cool down over the weekend. This was supportable in skis and sometimes boots. We measured it at 6-7” thick around 6000’ on sunny aspects. • Dug a snow pit in the Shed 11 path at 6400’, south aspect, 29° slope. Snow depth here was only about 20” and basically consisted of three layers: the recent snow, the recent crust under that, and then wet grains to the ground. Extended Column Test yielded ECTP 21 and 19 right underneath the crust (pit profile). • Dug a second snow pit in the uppermost reaches of Shed 10 at 7300’, ENE aspect, 30° slope. Snow depth here was 36” with only about 3” of recent snow resting on top of a 2” thick, 1F-hard crust formed over the weekend. Snowpack was dry throughout. ECTN14 just under the crust and CT12 Q2 on same layer. | • Avalanche activity today was limited to a few D1 wet loose on steep southerly slopes at elevations above 5500’. • Confirmed there were no slab avalanches in Path 1163 and Shed 10 last week during the warmup. Only the previously reported wet loose avalanches. • Excellent views today of distant terrain in the park and Flathead Range and no avalanches observed save for a few D1 wet loose and rollerballs. |
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| 2024-01-30 | 23:23:00 | Hanging Tree, I-Beam | Clark | • Ski tour up the ridge dividing the I-Beam and Hanging Tree Main avalanche paths on the west face of Running Rabbit Mountain. • Objectives were to investigate the recent avalanche activity in this area and look for any new avalanches. | • Scattered clouds with no precipitation and light winds from the SW. • Inverted air temperatures in the morning with a superficial refreeze of the surface snow up to about 5000’ elevation. Overnight temps only dropped to the high-30s °F above 5000’. • Daytime highs reached the mid-40s to low-50s °F on the Canyon floor and the mid-40s °F above 6000’ elevation. | • Snowpack is rapidly melting below 5500’ with plenty of bare patches showing up on sunny slopes. • We experience numerous audible collapse that became more frequent as we travelled above 6000’ elevation. • Snowpack structure is poor with facets around the late December crust along with faceted layers beneath the crust that are now becoming weaker with the presence of liquid water. | • No new avalanche activity observed today save for one little D1 wet slab we triggered while skinning up the ridge. This occurred at about 6800’ on a SW aspect, 38° slope. • Observed a more recent looking crown that likely ran yesterday on the east face of Snowshed Mountain in the Flathead Range, HS-N-R2-D2-O. • Hanging Tree Main also ran, likely sometime on Sunday, Jan. 28th, HS-N-R4-D2-O. This crown extended across the path. A few hundred feet below the crown, the debris gouged to the ground and took out the winter’s snowpack. Debris terminus location could not be determined. • We investigated the crown of the previously reported a large avalanche that ran in the I-Beam Main path, HS-N-R3-D3-O. o We suspect this ran sometime on Sunday, Jan. 28th. There was some more recent snow on the crown and inside some 2-3” cracks separating sections of slab that failed, but then arrested on the slope. o The failure layer was the faceted snow resting on top of the now much decomposed late Dec. crust (pit profile). o Debris ran about 1500 vertical feet to near 5800’ elevation terminating well above the highway. |
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| 2024-01-19 | 22:39:00 | Shed 7 and Shed 9 | Clark | • Ski tour up into the Shed 7 and Shed 9 avalanche paths then descended the Shed 5 path. • Objectives were to assess snowpack structure, perform welfare checks on the Shed 7 and Snowslip weather stations, and investigate an avalanche that failed last week in Shed 9. | • Broken or obscured skies above 6000’. Intermittent very light snowfall with trace accumulation by the end of the day. • Winds were calm on the Canyon floor and light from the SW above 6000’. • Inverted air temperatures and we were peeling layers as we climbed higher. Daytime high temperatures warmed to the high-20s °F above 6000’ but only reached about 10 °F on the Canyon floor. | • Starting to develop a clearer picture of the general snowpack structure across the Program’s terrain. o Below 5500-6000’, where there was little to no snow before the New Year, there is a layer of depth hoar at the base of the snowpack that has been buried by 2-3’ of snow from the January storms. Ski penetration is often still to the ground. o Above 6000’, where a more developed snowpack exists, the 2-4’ of snow from the January storms is resting on top of a weak layer of facets that rests on top of a stout melt-freeze crust from late-December. • Both weak layers are producing audible collapses and shooting cracks. I lost count of the number of audible collapses, but I have not experienced that many in one day for quite some time. • We did not trigger any avalanches on test slopes or from safe ridgelines that we traveled on. | • Can confirm the previously reported avalanche activity in Shed 7 West that ran the night of Jan. 17th. There were multiple soft slab crowns that failed in the storm snow, one nearing D2 size. • A very small, D1 soft slab ran the night of Jan. 17th in Umbrella Fence with debris burying a few wires in the slide fence • The avalanche in Shed 9 that ran sometime on Jan. 10th or 11th was a hard slab that failed on a layer of facets resting on top the late-Dec. crust (crown profile below) HS-N-R2-D2-O. o The crown ranged from 20-40” thick and was about 100 yards wide. o The slope angle where we dug into the crown was only about 30°. o It was difficult to tell how far the debris ran, but it appeared much of the mass only made it 500-700 vertical feet down slope before it was caught up in small trees. |
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| 2024-01-18 | 14:45:00 | Canyon Road Obs | Clark | • Windshield tours in the Canyon between Nyack and Marias Pass to look for recent avalanche activity. | • Snowfall and winds both died down around midnight last night. • Morning dawned with clear skies and calm or light easterly winds on the Canyon floor and light to moderate NE winds at ridgetop elevations • Temperatures warming to the single digits °F on the Canyon floor by the afternoon. | • Snowfall totals on the Canyon floor for the Jan. 17th storm ranged from 13-17” with 0.70-0.90” snow water equivalent. • Weather stations above 6000’ are reporting snowfall storm totals of 12-21”. | • There was a widespread cycle of small soft slabs failing in the new snow last night. These were generally small, destructive size 1-1.5 of 5 (D1-1.5) but noted some debris piles nearing D2 size. • Some notable avalanche activity above the rail included: o A couple D2 size debris piles in Path 1163 that ran about half path, terminating well above the grade. o A crown in Shed 7 West that may be pushing D2 size. Recent snow had covered up much of the evidence. Debris terminated up in the lower start zone well above the rail. o Multiple small crowns (D1s) in Shed 4D, Path 1164 and other similar steep cut banks. • Outside the Program Area on the nearby east face of Mt. Shields it appeared that a larger, hard slab may have failed on an older layer of snow buried deeper in the snowpack (photo). • Also observed some D1 to possibly D2 size crowns in the Cascadilla drainage. |
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| 2024-01-17 | 19:49:00 | Burnout to Shed 4D | Clark | • Windshield tours in the Canyon and a short tour up into the Burnout and Shed 4D avalanche paths. • Objectives were to assess the snowpack structure in this area and monitor the ongoing snowfall and wind loading. | • Overcast or obscured skies with heavy snow, S2, sometimes higher at times. Snow density is currently very light, about 5%. • Winds where light where I toured, but moderate to strong in the Canyon to the west. • Temperatures were in the single digits °F. | • Snowfall picked up last night and by 1700 hours the Canyon floor accumulated 5-9”. • Wind loading was severe between Java East and Devil Creek with fresh wind slabs forming on the Canyon floor. • On the ski tour I observed a few signs of instability such as some shooting cracks and audible collapses. These were at low elevations and likely occurred on a depth hoar layer. • There is about a foot of snow in the Burnout path with a layer of weak depth hoar at the ground (photo). No shooting cracks or collapses observed in this path. • Dug a snow pit in the Shed 4D avalanche path at 5800’ elevation on east facing slope (pit profile). Generally found soft, weak snow in the upper and mid-pack with a layer of facets on top the uppermost crust about 20” down from the surface. • Overall, the snowpack is weak and somewhat brittle and missing a cohesive slab resting on these weak layers. But I was mostly in wind-sheltered terrain and suspect conditions were more unstable where wind slabs are more prevalent. | • Observed a handful of small (D1) sluffs and soft slabs running on steep cut banks above Highway 2 and the Middle Fork. • Visibility of the avalanche terrain above the rail was very limited or non-existent. |
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| 2024-01-12 | 14:06:00 | Canyon Road Obs | Clark | • Windshield tours in the Canyon to look for avalanches following the storm. | • Awoke to mostly clear skies with occasional thin fog above 6000’. No precipitation. • Absolutely frigid. Overnight lows around -30 °F on the Canyon floor and down to -40 °F at upper elevations. It hasn’t warmed up much this afternoon. | • Trace of snow overnight with wind-loading finally tapering off and then gradually confined to ridge crests above 6500’ today with minimal transport. | • Another 4-10” thick, soft slab ran on a steep cutbank above the Middle Fork sometime last night. Failure layer looks to be depth hoar at the ground. • Visibility was much improved this morning and observed several avalanches in Railway terrain that ran sometime during the storm. Most events appeared to be wind slabs failing on the storm interface. All debris terminated well above the grade. o Multiple crowns (photo) in Path 1163 above 6000’ and seemed to be concentrated on the western side of the path. Crown thickness varied from 10-20+” with some running at least a couple hundred feet wide. Destructive size 1s and maybe some D2s. o Multiple crowns in the very upper reaches of Shed 10 above 7000’. Size D1.5-2. o A thicker (2-3’) wind slab (photo) ran in the upper reaches (est. around 6500’) of Shed 9, possibly size D2. Visibility of this terrain from the Hwy is very limited. • Other observed avalanches outside of the Railway terrain included: o A larger crown (D2+?) above Shields Creek on Snowslip Mtn, around 6800’ on a NE aspect. o D1.5 size crowns on a NE aspect above Devil Creek around 7000’ on the Devils Hump. |
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| 2024-01-10 | 20:06:00 | Canyon Road Obs and Shed 6 | Clark | • Windshield tours in the Canyon and a quick trip to investigate a small avalanche in Shed 6. | • The Arctic air arrived around daybreak today and temperatures rapidly dropped from the high-20s °F to the teens, then single digits, and now below 0°F. • Overcast skies today with moderate easterly winds and plenty of blowing and drifting snow. • Snowfall was very light for most of the day but picked up around sundown with rates of 1 to 2 inches per hour. • Air temperatures this evening above 6000’ range from 0°F at the western end of the Program to -18 °F at the eastern end. | • Snowfall last night totaled 4-6” on the Canyon floor with 5-10” above 6000’. • Another 2-3” accumulated on the Canyon floor today with 2-8” above 6000’. • Easterly winds intensified after the Arctic air arrived around daybreak. Blizzard conditions resulted and fresh wind slabs were forming at all elevations. | • One small slab avalanche just above the shed roof in Shed 6 located at 4600’ on an east aspect. o SS-N-R1-D1.5-O, crown was 5-10” thick (photo) and about 75’ wide. Debris ran about 100 vertical feet terminating above the shed. Failure layer was depth hoar at the ground. • Another small (D1) soft slab on a north-facing cut bank along Hwy 2 just east of Marias Pass (photo). Failure layer also appears to be some older snow and a persistent grain type. • No other avalanche activity observed. But visibility up into the higher terrain above the road was limited. |
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| 2024-01-09 | 21:13:00 | Grizzly Gulch | Clark | • Climbed up into Grizzly Gulch to a high point at 6500’. • Objectives were to observe the storm as it developed, assess new snowfall totals and wind loading, and check out how the new snow was bonding to the pre-storm surfaces. | • Overcast skies with moderate to strong SW winds and plenty of blowing and drifting snow. • Snowfall was most intense (S2) around daybreak, then tapered off and was intermittent in nature. After noon precipitation consisted entirely of graupel. • Daytime high air temperatures just reached the freezing mark on the Canyon floor and low-20s°F above 6000’. | • New snowfall from last night totaled about 2-3”. Another 2-3” accumulated on the Canyon floor today (0.20-0.40” water) and 3-4” above 6000’. Quite a bit less than expected. The uppermost 2-4” of today’s snowfall consisted entirely of graupel. • The storm may have lacked in precipitation, but it made up for it with wind. Moderate to strong SW winds were observed at all elevations. Extreme wind gusts were noted at ridgetop locations. • The wind affects and slight warming throughout the day created an upside layering in the upper snowpack with denser snow (wind slab and graupel) on the surface resting on top of low-density powder. • Despite this snowpack structure, signs of instability were limited where we travelled. Several ski cuts resulted only in minor cracking underfoot. The propagation propensity just wasn’t there. I suspect slabs were more developed and reactive in locations with more severe wind loading. • Dug a hasty snow pit on a southerly aspect at 6500’ in a location sheltered from the wind: Snow depth was 51” with about 24” of soft snow resting on top of a late-December crust. Extended Column Test resulted in ECTN6 about 6” down from the surface on the interface between the dense graupel layer and the lighter powder snow underneath. • The snowpack on the Canyon floor is finally about foot deep. | • No avalanche activity observed. | |
| 2023-12-26 | 22:23:00 | Second Slide, Shed 10, Grizzly Gulch | Clark | • Climbed up the Second Slide avalanche path, then further into the upper reaches of Shed 10, and then into the uppermost reaches of Grizzly Gulch to our high point on the summit of Running Rabbit at 7674’. • Objectives were to check on the snowpack structure in the uppermost elevation terrain, note the snowfall totals from 12/23, note any recent wind loading. | • Mostly cloudy with the bottom of the cloud ceiling hovering around 7000’ elevation. Occasional very brief snow flurries with no appreciable accumulation over the day. • Light SW winds with moderate gusts on the ridgetops. • Inverted air temperatures this morning with single digit values °F on the Canyon floor and low-20s°F above 6000’. Afternoon high temperatures reached the high-20s°F at all elevations. | • Very little snow below 6000’ elevation. “Storm” totals from 12/23 were 2-3” on the Canyon floor and 5-8” above 6000’. • Above 6500’ the snowpack generally consists of 5-8” of recent powder snow on top of the 12/22 crust (~1” thick), then another 5-10” of soft (4F) snow down to the 12/7 crust (2-4” thick), with melt-freeze crystals below that to the ground. Total snow depths ranged from 2-4’. • Below 6000’ the snowpack, where it exists, consists of 2-3” of powder snow on top of a sometimes boot-supportable melt-freeze crust to the ground. • Surface hoar was prevalent on the Canyon floor and up to about 5000’ where it gradually disappeared. • On sunny aspects, the snowpack surface was slightly stiffened by the recent solar heating/nighttime cooling, but no real crust was found. • No signs of instability observed. We cut a mini fridge-sized cornice chunk onto a steep northerly slope at about 7300’ with no results. • Recent wind-loading has been minimal at all elevations. | • Observed a handful of old Destructive Size 1 (D1), wet loose avalanches that ran last week during the warm weather. These were isolated to steep slopes on sunny aspects primarily between 6000-7000’ elevation. | |
| 2023-12-12 | 23:26:00 | Shed 11, Shed 10.7, Path 1163 | Clark | • Climbed the Shed 11/10.7 ridge to the Shed 11 weather station at 6400’ elevation. Then continued up the ridge above Shed 10.7 to the top of Path 1163 at 7200’. • Objectives were to check on the weather station and get into our upper elevation on the western end of the Program Area to check on conditions. | • A sometimes-broken stratus deck of clouds hung around 6500-7500’ elevation band all day with clear skies above. No precipitation. • Calm to light westerly winds with daytime high temperatures ranging from the low-20s°F above 6000’ to right around the freezing mark on the Canyon floor. | • Not much snow. 3-5” total snow depth on the Canyon floor, about 8-10” at 5000’, 12-18” at 6500’. Snow depths increased quickly above here with typical depths of 2-3’ around 7000’. Deeper snow exists on the shaded aspects. • Above-freezing temperatures and rain last week extended to at least 7200’ and likely much higher. • No signs of instability observed save for one propagating result in an Extended Column Test (see pit profile below). This occurred in a layer of moist facets below the Dec. 7th crust • The snowpack basically consisted of 5-10” of soft powder, newer snow on top, then the 2-4” thick Dec. 7 rain crust below that, then moist, rounding facets below that to the ground (pit profile). • The more recent snow resting on top of the Dec. 7th crust seems to be mostly stable. Ski cuts on some wind slabs atop the crust did not produce any cracking or slab releases. No fractures in this layer with ECTs. | • No avalanche activity observed. | |
| 2023-11-30 | 20:58:00 | Sheds 5, 7, 8, and 9 | Clark | • Climbed the Shed 6/7 ridge to the Shed 7 weather station at 6300’ elevation. Then continued up the ridge above Shed 7 West and Shed 9 to the Snowslip weather station at 7000’. • Objectives were to check on the weather stations and get into our upper elevation terrain that actually has snow to observe the conditions. | • Clear skies in JFS Canyon in the morning with light easterly winds and single digit °F temperatures. • Winds clocked to the S-SW around noon but remained light. Clouds increased throughout the day and by sunset a few snow flurries had begun. • Daytime highs reached the low-20s °F on the Canyon floor and the teens °F above 6000’ elevation. | • 0-3” of snow on the Canyon floor, thicker patches around 5000’, then a continuous snowpack from 6000’ on up ranging from about 5-20” deep (photo). Deeper snow exists on the shaded aspects. • The snowpack is generally weak and composed almost entirely of facet layers with some crusts interspersed between. • Snowpack surfaces consist of several inches of facets and widespread surface hoar (photo). • Southerly slopes that receive more direct daytime solar radiation had the least amount of surface hoar and a weak crust capping the surface with facets underneath. • No signs of instability today, but all this weak snow will become a concern once loaded by an overlying slab. | • No avalanche activity observed. | |
| 2023-11-14 | 19:54:00 | Shed 11 and JFS Canyon | Clark | • Climbed the Shed 11/10.7 ridge to the Shed 11 weather station at 6400’ elevation. • Objectives were to work on the weather station and observe the developing snowpack. | • Mostly clear skies with no precipitation. • Light westerly winds in the terrain I travelled through. But I could see small plumes of snow blowing off peaks reaching above 7000’ elevation by mid-afternoon. • Daytime highs reached the low-40s °F on the Canyon floor and near the freezing mark around 6400’ elevation. | • No snow on the Canyon floor. Sunny aspects around 5000’ had thin (2-3” deep), scattered patches of snow, mostly in the shade. • By 6000’ on sunny slopes the snow cover was more consistent, but still patchy in coverage and ranging from 5-10” deep. • The snowpack exposed to full sun was composed of a weakening melt-freeze crust (2-4” thick) on the surface with wet grains below that to the ground. • Snow in the shade was dry with a thinner breakable crust on top with rounding facets underneath. • Views of distant terrain indicated that the snowpack deepens considerably above about 6500-7000’ elevation, especially on shaded aspects. | • No avalanche activity observed on the terrain I travelled on. But there really wasn’t enough snow to create much if any avalanche hazard. • Visibility of distant terrain in the Flathead Range and Glacier National Park was excellent and no avalanche activity observed in the higher alpine terrain which has a deeper snowpack. |
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| 2023-04-07 | 16:30:00 | Shed 7 West | Steiner | • Ascended and descended the Shed 7 West avalanche path. • Objectives were to observe recent avalanche activity, snowpack structure, and weather conditions. | • Broken skies, No precipitation. • Light winds from the southwest. • Air Ts above freezing at all Program Area elevations. Into the 40s (*F) in the Shed 7 vicinity. • Overnight low air temperature in the Shed 7 SZ vicinity was a balmy 31*F. | • Isothermic snowpack on solar aspects at mid and lower Program Area elevations. • Other than isothermic conditions at mid and lower elevations, no obvious signs of instability. • No cornice failures observed. • No occurring or recent wind loading. • Surface snowpack was wet on all solar aspects in the Program Area. | • No recent avalanche activity observed. | |
| 2023-04-03 | 17:16:00 | Burnout to Shed 7 West | Clark | • Climbed the ridge above the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths to a high point at 6800’ elevation in Shed 7 West. • Objectives were to look for any recent avalanche activity, check out snowfall totals and wind loading from the Apr. 1st/2nd storm, and assess snowpack stability in this area. | • Clear skies in the morning, then building clouds and mostly overcast by late afternoon. Intermittent snow showers with trace accumulations. • Winds were light to moderate from the east or northeast with minimal blowing and drifting snow. • Overnight lows dropped to the single digits °F with the clear skies. But temperatures warmed quickly and reached to mid-30s °F on the Canyon floor and mid-20s°F above 6000’ by mid-afternoon. | • Snowfall totals from the Apr 1st/2nd storm have settled out to 2-3” on the Canyon floor, 5-6” at 5000’, and 6-10” at 6000’ and above. • Minimal wind loading today, but the newest crop of wind slabs formed over the weekend were 1-2’ thick and found on easterly and northerly aspects above 6000’. • Experienced 3 audible collapses/whumpfs. All occurred above 6500’ and on north-facing slopes. Hand pits revealed a 2-3” thick layer of facets right under the most recent snow as the layer of concern. • On other slopes where the pre-storm surface is a stout melt-freeze crust, the recent snow appears to be bonding well and no signs of instability were observed. • Snowpack surface was becoming moist at all elevations on slopes exposed to the intermittent sunshine by mid-afternoon. | • No recent avalanche activity observed. | |
| 2023-03-22 | 20:00:00 | Shed 7 West | Clark | • Field observations of any recent avalanche activity and to examine snowpack structure and stability in this path. | • Clear skies with light winds from the southeast. Air temps were 11 °F at the TH at 0930 and then rose to the mid-40s °F by late afternoon. | • Generally stable conditions today and beautiful weather. • Melt freeze crust snow surface was very firm and supportable throughout the tour on solar aspects but began to moisten/soften by 2pm, especially below 5k'. • Dug two snow pits today and both exhibited a generally stable rounding snowpack. • The SE pit was in the upper SZ of Shed 7 W on a SE aspect and was shallower and had more defined layer boundaries/hardness differences (pit profile). • The NE pit was on the ridge between Shed 7 W and Shields Ck, on a NE aspect, and had a deep, consistent, and strong snowpack (pit profile). • Our only stability test (PST in SE pit) resulted in stable results (59/100 END). Snow grains were only moist on the surface of the SE pit, and nowhere else. • No audible failures or obvious signs of instability. • No wind loading observed. Previous wind loading was not recent. | • No recent avalanche activity observed. • Path 1163 had a WL run sometime in the evening on 3/19. D2 and gouged down to deeper layers on its way down the path. Terminated at the 4600’ bench. • Old HS crown, D2.5, on the N face of Devils Hump West Summit at ~7200’. Maybe ran about 3/14 during the warm-up and rain and wind loading? Debris ran to at least 6500’. |
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| 2023-03-18 | 22:15:00 | Burnout to Sheds 5, 6, and 7-East | Steiner | • Welfare check on Shed 7 Wx Station. All looks good. • Field observations of any recent avalanche activity, snowpack condition, and weather. | • Clear skies with light winds from the southwest. Air temps in the mid-30s °F. | • No snow profile or stability tests conducted. • No audible failures or obvious signs of instability. • No wind loading observed. Previous wind loading was not recent. • Above 5200’ elevation on solar aspects, the upper 6” was becoming moist. • Above 5200’ elevation on non-solar aspects, surface snow had recrystallized. • Between 5200’ and 6000’ elevation on non-solar aspects, a stout crust remained intact below surface snow. • By late afternoon, below 5200’ elevation on solar aspects snowpack exhibited signs of being isothermal and cohesionless to the ground. Did not conduct a snowpack temperature profile. • On non-solar aspects below 5200’ elevation, surface snow had developed a melt-freeze crust with moist snow beneath it. (~1500 timestamp). | • No recent avalanche activity observed. | |
| 2023-03-15 | 21:00:00 | Burnout to Shed 7 East | Clark | • Climbed up the Burnout ridge. Continued on ridge above the Shed 4D, Shed 5, and Shed 7 E avalanche paths. Descended the same route. • In anticipation of the upcoming warm weather, our objectives were to observe the snowpack structure in this area and assess stability. | • Broken skies w S-1 snow showers and light winds till mid-day/ early afternoon. Then clouds lowered and snowfall intensity increased to S1-2. Winds remained light. | • We found a weak, unconsolidated snowpack below 5000 feet. Steep slopes at these elevations may be susceptible to wet snow avalanches that gouge below the surface. • At mid-elevations, this hazard would seem to be limited to sunny slopes, where the snowpack is weak, with one significant failure plane. • On shady slopes at mid elevations, the snowpack is well-consolidated, stronger, and more resistant to wet snow slides growing in size as they run. • We found 3-6" of fresh snow and few signs of recent wind loading below our high point at the Shed 7 Weather station (6300 ft). • On low-elevation easterly slopes (below 5000 ft), the snowpack is shallow (< 100 cm) and soft. A semi-supportable melt-freeze crust buried 3/14 exists on both sunny and shady slopes. On the former, it sits above moist/ wet snow. On shady slopes, the snow below the crust is drier but unconsolidated; it's easy to push a ski pole to the ground. On both sunny and shady low-elevation slopes, wet snow avalanches may gouge below the snow surface and quickly grow in magnitude. • At mid elevations, the difference between sunny and shady slopes is more pronounced (see snow profiles). The mid-January crust is two hard layers with a thin layer of softer snow between. On the sunny slope, a layer of large-grained, rounding facets was reactive in most but not all snowpack tests (ECTP4, CT 16 SC, ECTX). Though this structure was present on a shady slope, it was not reactive in tests. • The 3/14 crust extends to 6300 feet on the shady side of the ridge, though it was less than a cm thick at that elevation. It was thick and supportable on the sunny side of the ridge at that elevation and likely extends several hundred feet higher on steep slopes. We found shallow, 4F-hard slabs of drifted snow immediately on the lee side of the ridge above 5900; these were unreactive. | • No recent avalanche activity observed | |
| 2023-03-13 | 21:00:00 | JFS Canyon and Jakes | Clark | • Climbed up into the avalanche path known as Jakes to investigate the wet loose avalanche that gouged down into deeper layers in the snowpack yesterday afternoon. • Also, a couple windshield tours in the Canyon on the highway. | • Partly sunny in the morning, turning mostly cloudy, then fully overcast by late afternoon. • No precipitation until about 1600 hours when very light rain began, and it has been steady since then. • Daytime high temperatures reached the high-40s °F on the Canyon floor, the mid-30s °F at 6400’, and 29 °F at 7000’. | • Freezing levels climbed to somewhere between 6400’ and 7000’ elevation today. • High elevation winds were strong, and plumes of drifting snow were noted off the summit of Elk Mountain and other terrain features taller than 7000’. | • The avalanche in Jakes ran sometime between 1630 and 1830 hours yesterday. o It was a wet loose that initiated in the recent Mar 10th/11th storm snow at the top of the path around 5000’ (photo). o A few hundred feet down, the debris gouged down into a layer of weak rounding facets (pit profile) which increased the destructive size to a D2. o Associated debris was about 200’ wide and 1-4’ deep (photo) and terminated within 200 lineal feet of the rail, or about 80% distance to the grade. • Observed avalanche activity today was limited to more D1-D1.5 wet loose on steep slopes such as Shed 12, the Shed 4D Cutbank, and other steep cutbanks above the highway. No debris affecting the rail. |
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| 2023-03-12 | 18:19:00 | JFS Canyon and Little Dog Mtn | Clark | • Road observations from Hwy 2 and an off duty climb of SW ridge of Little Dog. | • Partly cloudy to mostly sunny skies by late afternoon. No precipitation with calm winds on the Canyon floor and light SW winds above 6000’. • Daytime high temperatures reached the low-40s °F on the Canyon floor and the high-20s above 6000’. | • Snowfall totals on the Canyon floor from Mar. 10th/11th ranged from 4-8” with the west end favored. • Recent snowfall totals at upper elevations ranged from 6-8” with very little wind affected snow at all elevations. • A couple old wind slabs produced some minor cracking (2-3’) underfoot. | • Recent avalanche activity above the rail today includes: o Path 1163, both the main path and the lower east headwall had multiple D1-D1.5 wet loose avalanches with debris stopping well short of the rail at 4800’ elevation. o Also, some minor D1 wet loose avalanches in Burnout, Umbrella, Shed 12, and a few steep cutbanks above the highway and river. No debris affecting the rail or Hwy. • Outside the Program Area: o Several loose dry avalanches running on steep, rocky high elevation terrain. Witnessed one dry loose D1.5 run on the east face of Point 8142’ just west of Little Dog at around 1300 (photo). Initiated at around 8000’ and ran to about 6800’. o Two old crowns (estimate D2 size) on the east face of Elk Mtn (photo). Unknown occurrence date and no other details known. |
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| 2023-03-07 | 17:00:00 | Cascadilla Drainage | Clark | • Ski toured into Cascadilla Creek for a close look at the previously reported very large (D3) avalanche on the east face of Nyack Mtn (photo). Continued up to the ridge crest dividing Cascadilla and Wahoo Creeks to a high point at 6700'. | • Overcast skies with occasional S-1 snowfall in the AM. Broken skies, no precip, and some occasional sunshine in the PM. Winds were generally calm or light from the west. • Daytime high temperatures reached the mid to high-teens °F at elevations above 5000’. | • No obvious signs of instability observed. No collapses or whoomphs. • No active windloading. Signs of previous wind loading evident at all elevations. | • No recent avalanche activity observed. • Debris from this very large hard slab on the east face of Nyack ran all the way down to at least 5000' elevation, possibly as low as 4600'. It was difficult to determine the exact terminus. This is a vertical fall of 2000-2500' and nearly a mile of lineal distance on the terrain. • Debris from this avalanche sympathetically triggered at least 5 additional slab avalanches, most D2 size. • Investigation of one of these smaller, debris-triggered crowns at 5100' on a NE aspect (photo) revealed the failure layer was facets right on top of the mid-Jan crust. • Skied out on E-SE aspects and crossed underneath several old crowns from the Feb 20th/21st cycle. There was about a foot of softer snow on top of the old bed surfaces which was the mid-Jan crust. |
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| 2023-02-28 | 22:44:00 | Shed 5 & 6 | Clark | • Ski toured in the Shed 5, 6, and 7 area while enjoying the company of a couple USGS avalanche researchers while on the skin track. • Objectives included: o Welfare check on Shed 7 East weather station. o Observe and evaluate snowpack structure at mid elevations in the Program Area. o Document recent windloading and/or any recent avalanche activity. | • Overcast skies with light snowfall accumulations throughout the day. • Light SW winds above 5500’ elevation. • Daytime highs reached into the upper 20s °F on the Canyon floor and into the upper-teens °F above 6000’ elevation. | • No obvious signs of instability observed. No collapses or whoomphs. • No active windloading. Signs of previous windloading evident on all aspects. • Substantial previous crossloading of mid and upper elevation starting zones in the Program Area. Particularly in the starting zones of Shed 5 and Path 1163. • Excavated a test pit at ~6000’ elevation, SE aspect, 30° slope to investigate and test the persistent weak layers of concern that are deeply seated in the snowpack. o Total snow depth was 170 cm (67”). o The Feb 20th/21st pre-storm interface was at 105 cm (26” down). o The mid-Jan. facets/crust interface was at 65 cm (40” down). o The late-Dec. facets/crust interface was at 45 cm (49” down). o The first Extended Column Test yielded no fractures (ECTX) o Compression Test resulted in CT22 Q2 at the Feb 20th/21st storm interface. o Deep Tap test performed over the mid-Jan facets/crust resulted in DT25 Q2 on facets just above the late-Dec. crust. o Still curious, we removed 14” off the top of our 2nd ECT column and repeated the test. We had propagation at 30 taps on the facets atop the late-Dec. crust with the block then sliding into the pit. o Finally, a Propagation Saw test on the facets above the late-Dec. crust resulted in 65/125 END. | • No recent avalanche activity observed. • A small (D1.5) slab avalanche ran in the Test Slopes on the Shed 6/7 ridge sometime during the Feb. 20th/21st storm. • From the highway we saw the crown of the large hard slab avalanche that the FAC team investigated on Sunday, Feb. 26th. This is on the east face of Snowshed Mtn. and just outside of the Railway Program Area (photo). |
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| 2023-02-27 | 19:40:00 | Path 1183 | Clark | • Climbed the ridge between Path 1183 and Cascadilla Ck, over Point 5968’ and down the ridge to the north between Path 1183 and Wahoo Ck. • Objectives were to look for recent avalanche activity and assess snowpack stability and structure in this area. | • Overcast skies in the AM with broken skies in the afternoon. A few S-1 snow flurries in the morning. • Winds were generally calm or light from the west. • Daytime highs reached near freezing or just above on the Canyon floor and the low-20s °F near 6000’ elevation. | • We experienced 4 audible collapses. These occurred between 5100-5400’ elevation and on an east-facing ridgeline. • Minimal wind loading in this area over the past 24 hours. Old wind slabs were unreactive to ski cuts. • Dug a snowpit at 5400’ on and east facing aspect and adjacent to the 1183 avalanche path. o Here the snow depth was ~60”. We found a poor structure snowpack with a F to 1F-hard slab on top of weak faceted snow around the mid-January crust. We had propagating results (ECTP22) in an extended column test on a layer of facets above the mid-January crust. The slab above this weak layer is roughly 2’ thick. • The surface snow is faceting. • 1-2” new snow on the Canyon floor since Feb. 24th. | • Path 1183 did not avalanche during the Feb. 20th/21st avalanche cycle. • Observed numerous (15+) avalanche crowns ranging from D2-D3 size in both Cascadilla and Wahoo Creek basins that ran during Feb. 20th/21st. Many of these appeared to be thick crowns (2-4+’) that extended several hundred feet across the slope, and likely ran on older, buried persistent weak layers. |
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| 2023-02-21 | 18:40:00 | JFS Canyon | Clark | • Road observations in the Canyon. • Objectives were to look for recent avalanche activity, measure new snowfall in the Canyon, and determine the extent of recent wind loading. | • Overcast/obscured skies in the AM, gradually clearing by late afternoon. Another 1” of snow accumulated on the Canyon floor today. • Winds were generally moderate with strong gusts from the east at all elevations. • Temperatures dropped throughout the day, from 10-15 °F to the single digits currently on the Canyon floor. Above 6000’, temperatures plummeted from the mid-20s °F this morning to -11 to -6 °F currently. | • The Feb. 19-21 storm was a bit slow to start but finished strong with 1.00” of water on the Canyon floor overnight and over a foot of snow (settled measurement) above 6000’. Hourly snowfall rates of 1-4” per hour were observed at high elevation weather stations. • Storm totals for the period (Feb. 19th, 1200 hrs. through Feb. 21st, 0700) reached 1.47-1.75" water with 7-12” of snow on the Canyon floor and 15-25” (settled measurement) of snow above 6000’. • Wind-loading over the past 48 hours has been heavy. • Large cornices are present in Shed 7 West and Infinity. | • Path 1163: SS-N-D2, debris ran to 4600’ elevation and within and 900 lineal feet from the grade (82% distance to the rail). Visibility was limited and no crown observed. But from debris and gouging in the track, it appears to have initiated at the top of the path. R-size, failure layer, and other details unknown. • Infinity: SS-NC-R2-D2-I debris ran to 4500’ elevation and within 400 lineal feet from the rail (85% distance). Looks to be a cornice fall that likely triggered a slab beneath, ~100’ wide, crown mostly filled back in, but less than 2’ thick, failure layer looked to be the old/new snow interface. • Shed 10 East Feeder: SS-N-D1.5, debris terminated well-above the rail. No other details known. |
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| 2023-02-19 | 23:26:00 | Burnout to Shed 7 West | Clark | • Climbed the east ridge of Snowslip Mtn above the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths. Descended the same route. • Objectives were to assess snowpack and stability in this area with particular attention to the facets between the two prominent crusts buried in the mid-pack and the extent of recent wind loading. | • Overcast skies with light to moderate snowfall (S1 to S2). • Daytime high temperatures reached the low-30s °F on the Canyon floor and the low-20s °F above 6000’. | • Since Friday, Feb. 17th through midday today, the Canyon floor picked up 3-4” of snow with 0.30” SWE. Upper elevations accumulated 5-7”. • Snowfall rates increased around noon today and the Canyon floor has picked up another 3-5” with 0.25-0.30” SWE since then. Another 4-6” has accumulated at elevations above 6000’. • Moderate to strong westerly winds produced heavy wind-loading at times above 6000’. • Ski cuts on fresh wind slabs resulted in only minor cracking underfoot or no cracking at all. • Dug a hasty pit near the Burnout path at 5200’ on an east aspect, snow depth was 39”. ECTP25 and ECTP20 on a layer of facets between the mid-Jan. and late-Dec. crusts about 14” down. • Dug a second hasty pit at 5800’ on an east aspect, snow depth was 69”. Just some ECTNs in the upper 20” with no fractures on the facets (~30” down) between the above-mentioned crusts. • The mid-Jan. crust was buried 30” down below the surface in Shed 7 W at about 6600” and the late-December crust was buried about 40” down. • Cornices are growing large in Shed 7 West (photo). | • No avalanche activity observed. | |
| 2023-02-15 | 22:30:00 | Tranquil Basin to Radar Point | Clark | • Climbed the Tranquil Basin uptrack, paralleling the creek, then up the west face of the Devils Hump to the ridge crest, then out to the point at the top of Larry and Curly. | • Broken skies with occasional very light snowfall. Minimal accumulation throughout the day. • Daytime high temperatures reached the high-20s to low-30s °F on the Canyon floor and the mid-teens above 6000’. | • About 1” of new snow on the Canyon floor and 4-6” above 6000’. • No signs of instability observed. Ski cut a couple fresh wind slabs with only minor cracking underfoot or no cracking at all. • Light to moderate SW winds above 6000’ elevation were occasionally loading leeward slopes just below ridgelines. But minimal wind loading over the course of the day. | • No avalanche activity observed. | |
| 2023-02-13 | 21:57:00 | Second Slide | Clark | • Climbed into the upper starting zone of the Second Slide avalanche path via the ridge to the west. Descended the same route. • Objectives were to look for any recent avalanche activity and assess the snowpack structure and stability in this avalanche path. | • Broken or overcast skies with light rain or rain/snow mix on the Canyon floor and light snowfall above 5000’ elevation. • 2” of new snow today above 5000’ feet and a 0.25” water on the Canyon floor by the time precipitation ended around 1600 hours. • Moderate westerly winds with strong gusts at mid/upper elevations with winds subsiding around 1600 hours. • Canyon floor temperatures were in the low-40s °F in the morning and cooled as the day progressed, finally dropping below freezing around 1700. | • Poor snowpack structure persists between 5000’ and my high point at 5500’ elevation with weak facets below the mid-Jan. crust and a building slab on top. This slab is now 1-2’ thick. • No signs of instability observed. Ski cut a couple fresh wind slabs with only minor cracking underfoot or no cracking at all. • Moderate to strong W-SW winds, predominantly above 5000’ elevation, were actively loading leeward slopes (photo) until late afternoon when the winds began to calm down. • Dug a snow pit and conducted a full profile at 5300’ elevation on a SE aspect, 35° slope (see pit profile below). Found a poor snowpack structure with a layer of facets below the mid-Jan crust about 16” below the surface. Unstable result with the first Extended Column Test, ECTP24 on said facet layer, but then ECTN25 with the second test on the same layer. | • No avalanche activity observed. | |
| 2023-02-07 | 20:26:00 | Devils Hump | Clark | • Climbed into the unnamed basin directly to the north of the twin peaks of the Devils Hump. Climbed to the saddle between the two peaks at 7200’ and descended the ascent route. • Objectives were to look for any recent avalanche activity and assess the snowpack structure and stability in this area with particular attention to the recent wind-loading. | • The morning had broken skies with the occasional sunshine. By noon skies were overcast and by 1400 S-1 to S1 snowfall with elevations above 5500’ favored. • 1” of new snowfall above 5000’ on our exit and a trace on the Canyon floor. • Daytime highs reached the mid-30s °F on the Canyon floor and the low to mid-20s °F above 6000’ elevation. | • Poor snowpack structure predominantly above 5000’ with weak facets above/below the mid-Jan. crust and a building slab on top. This slab is now 1-2’ thick. • Some facets noted on top the late-Dec. crust as well, but these layers were harder and rounding. • Despite the poor structure, no signs of instability observed, save for some minor cracking underfoot. We could not release any slabs on small, steep test slopes, nor get any shooting cracks. • Moderate to strong S-SW winds, predominantly above 5000’ elevation were actively loading slopes just below ridgelines on northerly and easterly aspects. • We stayed down in the middle of the basin and limited our terrain choices to slopes most sheltered from the wind and lower than 35°. Avoided consequential slopes that were steeper than this and had rock outcrops and/or unsupported slopes above cliff bands. | • No recent avalanche activity observed | |
| 2023-02-02 | 22:41:00 | Shed 11, Shed 10.7, Path 1163 | Clark | • Climbed the Shed 11/10.7 ridge to the weather station and then up the SW ridge of Running Rabbit to the uppermost reaches of Path 1163. Joined by Rob Millspaugh with the Flathead Avalanche Center. • Objectives were to assess snowpack structure and stability in this area, look for recent avalanche activity, particularly in Path 1163, and check on the weather station. | • Mostly clear skies with brilliant sunshine. • Light westerly winds below 6500’ and light to moderate westerlies at elevations above. • Daytime highs reached the high-30s °F on the Canyon floor and the mid to high-20s °F above 6000’ elevation. • Surface snow became moist on solar aspects by mid-day. A thin crust was just developing as these became shaded. | • A concerning snowpack structure is developing with weak facets above/below the mid-Jan. crust and now a slab building on top (pit profile). • The mid-Jan crust thinned and pretty much disappeared by 7000’ in this area. • Some minor cracking (2-4’ long) in old wind slab above 5000’ in addition to the small ski-triggered avalanches (photo). • Light to moderate wind loading from westerly winds above about 6500’ on the tour and in surrounding terrain. • Dug a snowpit and recorded a profile in the Shed 10.7 Feeder path on SE aspect at 6250’. Propagation with moderate force x2 on a layer of facets beneath the mid-Jan. crust. This was about 14 down from the surface (see pit profile). | • Naturally triggered D1-1.5 wet loose ran this afternoon in Path 1163 Headwall and Jakes. Debris terminated above the rail. • Intentionally triggered D1 wind slabs from ski cuts on SW ridge above Shed 11 weather station. 4-8” thick slabs with propagation reaching 20’ max (photo). |
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| 2023-01-28 | 15:20:00 | JFS Canyon | Clark | • Road observations in the Canyon. • Primary objective was to look for avalanche activity after recent snowfall and wind loading. | • Partly sunny skies with no precipitation and light to moderate E winds on the Canyon floor and moderate N-NE winds above 6000’. • Daytime highs only reaching single-digits °F on the Canyon floor and negative single-digits °F above 6000’ elevation. | • The Jan. 26-28 storm was a dud here in JFS Canyon. Forecast on Jan. 26 calling for 10-20” new snow with up to 1.00” water. Instead, Canyon floor received 2-3” and 0.30” water. HST totals at Shed 11 were 10” (suspect some wind-loading) and 4” and Shed 7. • Arctic air pushed around 0100 last night. Some serious near-surface faceting going on now in the upper 5” of the snowpack. | • Path 1163 – D2 debris pile ran to 4800’ on the bench. Appeared avalanche started from uppermost path in the center, but visibility was limited. Dry SS debris and likely a recent wind slab. • Shed 10 Feeder - D2 debris pile just below confluence with the main path. Dry SS debris and likely a recent wind slab. |
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| 2023-01-17 | 18:42:00 | Shed 7 and Shed 9 | Clark | • Climbed the Shed 6/7 ridge to the Shed 7 weather station, then continued up to the Snowslip weather station and descended the Shed 9 path. • Primary objective was to repair the Shed 7 weather station, but also needed to assess snowpack structure and stability in this area. | • Overcast or broken skies with very light snowfall and a trace of accumulation throughout the day. • Light SW winds above 5500’ elevation. • Daytime highs reached the low-30s °F on the Canyon floor and the mid-20s °F above 6000’ elevation. | • A new crust formed after the recent cool down and extends from the Canyon floor (~1/2” thick) up to about 7000’ (high point of the day) where it’s about eggshell thickness. • New snow depths on top of this latest crust were about 1” on the Canyon floor and 2-4” above 6000’ in non-wind loaded locations. • No wind loading until above 6000’ elevation and then this was minimal. Found some new wind slabs (6-10” thick) near ridge crests on easterly and northerly aspects, but these were unreactive with no shooting cracks from ski cuts. • Below 5500’ the snow is moist between the mid-January crust and the late-Dec/Christmas crust below. By ~6000’ the snow between the two crusts was dry with some notable facet layers but could not find any buried surface hoar. • Dug a hasty pit in the upper reaches of Shed 9 at 6400’ on a SE aspect. Snow depth was about 47”. Extended Column test yielded some ECTNs right below the mid-Jan crust and then ECTP28 on 1-2 mm facets right above the Christmas crust (~22” below the surface, mostly 1F hard snow save for the newest snow on the surface) with the column sliding into the pit. Did a 2nd test and the same layer failed again only with less force, ECTP13. | • No recent avalanche activity observed. | |
| 2023-01-03 | 22:25:00 | Shed 11, 10.7 and Path 1163 | Steiner | • Ski toured on ridge between Shed 10.7 and Shed 11. Continued up the SW ridge of Running Rabbit Mtn. to the South Summit. Descended Upper Shed 10 gallery into the Shed 10 Path proper. • Objectives included: o Observe avalanche activity in the Shed 10 Path. o Evaluate surface snowpack conditions and interface. o Document recent windloading and/or any recent avalanche activity. | • Overcast skies with very light snowfall with a trace of accumulation throughout the day. • Light SW winds above 5500’ elevation. • Daytime highs reached into the 20s °F on the Canyon floor and into the mid-teens (0F) above 6000’ elevation. | • No obvious signs of instability observed. • No active windloading. Signs of previous windloading evident on easterly/ northeasterly aspects. • Facets are forming on the interface between most recent snow accumulation(s) (10-15”) and the Christmas rain crust. This crust is ~2” thick at 6500’ and then thinned to less than half an inch at our high point at 7300’. • Surface Hoar, up to 8mm, was observed on shaded aspects between ~5,500 feet elevation and ~6,200 | • No recent avalanche activity observed. • Examined previous avalanche activity, already reported, in the Shed 10 Path. o This avalanche, as previously reported, released in the Shed 10 Feeder Path on the evening of December 20/21st. o This avalanche entrained dry snow, was fast moving, and terminated at 4500’ elevation above the rail grade (HS-N-R4-D2.5-O). o After today’s evaluation, this avalanche’s size was larger than originally estimated during highway observation on 12/21/22 and runout distance was also substantially greater than had been previously estimated. |
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| 2022-12-30 | 22:29:00 | Sheds 5, 6, and 7 | Clark | • Ski tour into the bottom of Shed 6, then up the ridge between Shed 5 and 4D, and onwards to Shed 7 East and West. • Objectives included: get an up-close look at the avalanche activity that has occurred over the past 10 days, assess the current wind loading, examine the snowpack structure, and assess stability in this area. | • Overcast skies with light snowfall and about 2” accumulation during the day. • Moderate SW winds above 5500’ elevation. • Daytime highs reached about freezing on the Canyon floor and the mid to low-20s °F above 6000’ elevation. | • We ski cut multiple wind-loaded test slopes with no reactivity minus the one D1 slab. • Moderate westerly winds were activity loading slopes above 5500’. The Shed 7 West cornice has grown to 10+ feet (photo). • Dug a hasty pit in the upper reaches of Shed 7 East, 6300’, SE aspect. Snow depth was 47” with 10” new snow on top of the late Dec. crust which was 4” thick and pencil hard. Extended Column Test yielded ECTN25 about 25” down under the Nov 25th crust. Deep Tap test on facets at the base of the column resulted in DT28 Q3. • Dug a second snowpit in Shed 7 West, 6700’, SE aspect. Snow depth was 59” with 12-18” of recent snow on top of the late-Dec crust which was more of a crust sandwich composed of 3 thin rain crusts with facets/DFs between. A couple ECTNs on the new snow interface, then ECTP28 19” down right under the lowest crust of the sandwich (photo). Next test gave ECTN29 on the same layer. | • Ski cut one D1 wind slab (4” thick by 20’ wide) at 5600’ on a SE aspect on a steep (45+ deg) gully sidewall. • No other recent avalanche activity observed. • Investigated a few previous avalanches (all previously reported) including: o D1-1.5 wet loose and wet slabs in lower Shed 6. These failed on facets near the ground during the Dec. 27 warm up and rain with a couple running within 50 yards of the Shed. o D2.5 soft slab in Shed 7 West triggered by a falling cornice on Dec. 26th likely failing on the Dec. 20th pre-storm interface. Ran 1600’ vertical terminating 2/3rd path above the rail at 5200’. o D2.5 hard slab that ran during the Dec. 20th storm. This avalanche was larger than originally estimated from the highway. It failed on the Nov. facets near the base of the snowpack and a thin ribbon of debris extended 1700 vertical feet down the path to within 50 feet of the snowshed. This avalanche broke trees up to 12” thick and the crown was estimated at 400-500 feet wide. |
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| 2022-12-13 | 22:52:00 | Shed 11, Shed 10.7, and Path 1163 | Clark | • Road observations and a ski tour up the Shed 11/10.7 ridge and higher to the upper starting zones of Shed 10.7 and Path 1163. • Objectives included: look for any recent avalanche activity, assess the current wind loading, examine the snowpack structure, and assess stability in the west end of the Program Area, and make a welfare check on the Shed 11 weather station. | • Overcast skies with occasional very light snowfall. Winds were calm or occasionally light from the west. • Daytime highs reached the low-20s °F on the Canyon floor and the high teens °F above 6000’ elevation. | • We ski cut multiple wind-loaded test slopes above 5000’ on the Shed 11 ridge resulting in several short (2-6’ long) shooting cracks in the uppermost 4-8” of snow consisting of recent wind slab (photo). • Fresh crop of surface hoar growing on the snowpack surface starting around 5500’ and becoming more developed and widespread as we climbed higher. • One “rolling thunder” audible collapse that carried a couple hundred feet across a slope at 6800’ on a southerly aspect on the ridge just west of the Shed 10.7 path. • Dug a snowpit and conducted a full snowpack profile on the ridge just west of Path 1163 at about 7000’ elevation (see pit profile). Poor snowpack structure here with two propagating results in an Extended Column tests on the Nov. facets about 30” down. Also, a second propagating result about 10” down on the 2nd test. • Multiple hasty and hand pits revealed the same story here as in the eastern end of the Program Area – a widespread poor snowpack structure with a consolidating slab 1-3+ feet thick resting on top of a sometimes-reactive layer of facets formed back in November. | • No recent avalanche activity observed. • It was hard to confirm from a distance, but it appears the large avalanche on the SE face of Snowshed Mtn (observed on Dec. 4th) ran full path to Sheep Creek. |
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| 2022-12-07 | 18:05:00 | Shed 6/7 ridge and Shed 5 | Clark | • Road observations and a ski tour up the Shed 6/7 ridge then up and over into the Shed 5 path. • Objectives included: look for any recent avalanche activity, assess the current wind loading and perform some ski cut stability tests in the “Test Slopes”, and assess the snowpack structure in Shed 5. | • Overcast skies with occasional light snowfall. Winds on the Canyon floor were light from the west. Winds above 5000’ were light to moderate from the southwest and were occasionally transporting snow. • Daytime highs reached the high 20s °F on the Canyon floor and the high teens °F around 6000’ elevation. | • We ski cut several wind-loaded test slopes on the Shed 6/7 ridge and all but one was unreactive with only 4’ long shooting crack (photo). This was in a fresh wind slab at around 5200’ elevation on an easterly aspect. No collapses today. • Dug a snowpit and conducted a partial snowpack profile in the upper reaches of the Shed 5 avalanche path (see pit profile). Found a poor snowpack structure with a layer of buried surface hoar (observed on the surface on Dec. 4th) about 12” down and the Nov. facets layer of despair 28” down. • Extended Column Tests resulted in one propagating and one non-propagating result with moderate force on the surface hoar and the Nov. facets propagated twice with hard force. • Multiple hasty and hand pits revealed the same story – the poor snowpack structure appears to be widespread with a consolidating slab 1-3+ feet thick resting on top of a sometimes-reactive layer of facets formed back in November. | • No avalanche activity observed. |
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| 2022-12-04 | 22:26:00 | Flathead Range & Burnout to Shed 7 | Clark | • Road observations along Hwy 2 as well as a ski tour up the ridge above the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths. • Objectives included: look for any recent avalanche activity, observe snowfall totals from the recent 11/30-12/2 storm, assess snowpack structure and stability, and work on the Shed 7 weather station. | • Glorious day with clear skies, abundant sunshine, and calm or light N winds. • A minor temperature inversion with daytime highs only reaching 10-14 °F on the Canyon floor and the mid to low-20s °F around 6000’ elevation. | • Heard and felt two major collapses on sparsely timbered slopes at 5900’ and 6100’ elevation on E-SE aspects. In one instance the snowpack’s groaning whumph carried more than 50 yards across the slope. These collapses would shake the snow out of small trees but did not result in shooting cracks. • Dug a snowpit and conducted a partial snowpack profile in the upper reaches of the Burnout avalanche path (see pit profile). Found a poor snowpack structure with propagating results during and Extended Column tests • Multiple hasty and hand pits revealed the same story – the poor snowpack structure appears to be widespread with a consolidating slab 1-3+ feet thick resting on top of a reactive layer of facets formed back in November. | • Avalanche activity observed in terrain above the rail was limited to a couple cornice breaks which popped out a two D1.5 wind slabs in uppermost Shed 7 West. • However, in the nearby Flathead Range we noted two separate crowns: one on the east face of Cameahwait (estimated size D2.5) and another on the east face of Snowshed (estimated D2 size). • Our Essex Signal Maintainer reported a very large crown on the SE face of Snowshed Mtn above Sheep Creek (photo and estimated D3 size). • The avalanches in the Flathead Range all appeared to have run on the weak faceted snow formed in November. We could not view runout and debris for any of these slides and estimate that they ran late last week during the storm. |
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| 2022-11-29 | 17:32:00 | Shed 7 | Clark | • Climbed the Shed 6/7 ridge to the top of the Shed 7 East avalanche path, then moved up into the upper reaches of the Shed 7 West path. Descended the Shed 4D/5 vicinity. • Objectives included: look for any recent avalanche activity, observe snow depths and general snowpack structure in this area, and note the extent of recent wind loading. | • Mostly overcast skies with occasional very light snowfall (S-1). • Calm winds or light northerly winds clocking to the SW by the afternoon. • Daytime highs reached 10 °F on the Canyon floor and hovered in the single digits °F around 6000’ elevation. . | • Previous wind transport and loading was notable at elevations above 5000’, primarily on easterly aspects with new wind slabs up to a foot or more thick. Ski cuts produced some minor cracking (2-4’ long) underfoot. • Noted some minor whumpfing and collapses on the underlying facets on the Shed 6/7 ridge in areas with shallow snow depths between 5500-6000’ elevation. • Winds were mostly calm but some blowing snow noted on distant ridges above 6500’ as westerly winds picked up in the afternoon. • Dug a snowpit and conducted a full snowpack profile in the upper reaches of the Shed 7 East path (see pit profile). Found a few notable layers of weak facetted snow, but no propagating results with an Extended Column Test. • Dug a hasty pit in the Shed 7 West upper starting zone at 6600’ elevation on an easterly aspect. Very similar snow depth (~3 feet) and structure as in Shed 7 East. Extended Column Tests resulted in a couple non-propagating results in the upper 12” and a third at the ground. | • Very small (D1 size) cornice-fall observed in Shed 7 West, at least a couple days old. • No other avalanche activity observed. |
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| 2022-11-28 | 16:40:00 | Second Slide | Clark | • Climbed the SE ridge of Running Rabbit Mtn adjacent to and east of the avalanche path known as Second Slide to a high point at 5600’ elevation. Descended the ridge to the west of the path. • Objectives included: look for any recent avalanche activity, observe snow depths and general snowpack structure in this area, and note the extent of recent wind loading. | • Mostly overcast skies with rare breaks showing some blue sky. No precipitation. • Light winds from the east with the occasional moderate gust. • Daytime highs reached 10-15 °F on the Canyon floor and hovered in the single-digits °F around 5000’ elevation. | • Previous wind transport and loading was notable at elevations above 5000’, primarily on easterly aspects with new wind slabs up to a foot thick. Post-holing and stomping on several wind loaded test slopes resulted in no cracking or slab releases. • Winds clocked to the east-northeast overnight but were mostly light and minimal wind loading was observed today. • Below the most recent new snow (2-3” on Canyon floor, 4-5” around 5000’) and wind slabs there is a melt-freeze crust from the Nov. 25th warm-up/cool-down. Below this crust the snowpack consists mainly of facets, or on more open, sun-exposed slopes, alternating layers of facets with additional older crusts down to the ground. | • No avalanche activity observed. | |
| 2022-03-28 | 15:42:00 | US Highway 2, JFS Canyon | Clark | Observations today made from the highway. | • High temperatures over the weekend reached the low-60s °F on the Canyon floor and the low-50s °F at weather stations located at ~6400’ elevation. • Today was another mostly sunny day, with light westerly winds, and temperatures reaching the high-50s °F on the Canyon floor and the high-40s °F at ridgetop locations. | • Full spring conditions now with a rapidly melting snowpack at low-mid elevations. Weather stations on the Canyon floor lost 4-7” of snow depth over the weekend. • Weather stations above 6000’ elevation are reporting a loss of 10-12” of snow depth due to settlement and melt since Thursday, March 24th. • Many of the low elevation avalanche paths on sunny aspects such as Second Slide (MP 1162.5), Jakes (MP 1161.9), Umbrella Fence, and the Shed 4D Cutbank have mostly melted out. | • New avalanche activity that occurred over the weekend included: o Destructive sized 2 (D2) wet loose avalanche in Path 1163. Associated debris ran about ¾ path terminating above the grade. o A D2-size cornice fall avalanche in Shed 7 West. Associated debris ran about ½ path terminating above the grade (photo). o Most notable was a D3-size hard slab that failed in a path known as I-Beam. This path threatens U.S. Highway 2, but not the rail grade. The debris terminus was not visible, but it did not reach the highway (photo). |
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| 2022-03-17 | 19:17:00 | Burnout to Shed 7 West | Clark | • Ascended the ridge above the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths. Descended the same route. • Objectives were to look for recent avalanche activity, assess the snowpack structure and stability in this area, and perform a welfare check on the Shed 4 and Shed 7 weather stations. | • Broken skies in the AM gave way to mostly clear conditions by the afternoon. No precipitation all day. • Calm winds on the Canyon floor and light SW winds at upper elevations with moderate gusts. • Air temperatures reached the mid-40s °F on the Canyon floor and the low-30s °F above 6000’ by the afternoon. | • Snowfall totals for March 15th/16th ranged from 2-4” on the Canyon floor to 7-12” above 6000’. • Below about 5500’ the snowpack was mostly wet throughout. Above this elevation the surface was wet on the surface on sunny aspects. • Above 6000’ the facets resting atop the early March crust were buried 1-3’ deep. • We experience one audible collapse at 6100’ on a north aspect. We expected additional collapses further up the ridge on similar aspects, but none occurred. • Minimal wind loading from the mostly light SW winds above 6000’. • Dug a hasty pit in the Shed 7 W avalanche path at 6700’ on an easterly aspect. Snow depth was 104”. ECTN14 and CT14 Q2 on the most recent storm interface about 12” down. The early March facets/crust were buried 20” down produced no fractures. • Dug a second hasty pit on a northerly slope in the Shields Ck. basin at 6700’. Here the early March facets/crust were buried about 32” deep and produced no fractures during stability tests. | • Recent avalanche activity included: o Multiple wet loose avalanches up destructive-size 1.5 (D1.5) ran this afternoon in Path 1163. Debris ran ½ path terminating well above the rail. o A D1.5-sized slab failed on an easterly slope just below a ridgeline at 6800’ in the Shields Ck basin, outside of the Program Area. Likely a wind slab, about a foot thick and 100’ wide. o A larger, at least D2-size slab on an easterly aspect at about 7200’ above Devil Creek. This may have run yesterday or the day before and may have failed on the facets associated with the early March crust. • During the March 1st avalanche cycle a cornice fall triggered a small-medium sized slab in Shed 7 West. Remnants of the crown were still visible today. Associated debris was D2 size and terminated well above the grade (photo). |
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| 2022-03-13 | 16:35:00 | Sheds 11 and 10.7 and Path 1163 | Clark | • Ascended the ridge between the Shed 11 and Shed 10.7 avalanche paths to the Shed 11 weather station. Continued to the top of Path 1163 at 7200’. Descended the Shed 10.7 and Path 1163 area. • Objectives included: assess snowpack structure and stability in this area, look for any recent avalanche activity, determine the runout distance of the avalanches that ran in Path 1163 during the early March cycle, and perform a welfare check on the Shed 11 weather station. | • Overcast or obscured skies with light to moderate snowfall beginning around 0900. • As temperatures warmed the rain/snow line crept up to about 5500’. 1-2” of snow had accumulated over the skin track at upper elevations by early afternoon. • Calm winds on the Canyon floor and light SW winds at upper elevations. • Air temperatures reached the high-30s °F on the Canyon floor and the mid-20s °F above 6000’ by the afternoon. | • Below about 5500’ elevation the snowpack surface was a firm and supportable melt-freeze crust in the AM, but this had softened by early afternoon. • At about 5500’ there is 1-2” of more recent snow on top of the early March rain/melt-freeze crust and by 6500’ there is about a foot. A sometimes-breakable sun crust capped this newer snow on sunny aspects. • The buried early March crust is nearly 3” thick at 6400’, but quickly thins to less than half an inch by 6800’ and is gone by 7200’. Immediately above this crust there is a layer of weak faceted snow 1-3” thick. • Dug a hasty pit in the uppermost reaches of Path 1163 at 7200’ on an easterly aspect. Snow depth was 71”. The layer of faceted snow noted above was 15” below the surface here and resting on a 1F hard windslab instead of the early March crust. ECTN15 and CT21 Q2 on this faceted layer. • Minimal wind-loading observed on the tour. Older wind slabs were locked down under the mentioned sun crust and unreactive to ski cuts. | • No recent avalanche activity observed. • Both Shed 11 and Shed 10.7 slid around March 1st. These were relatively small wet loose slides, Destructive size 1.5 of 5 that terminated well above the grade. • The debris from the early March avalanches in Path 1163 was a little larger than estimated from the Hwy, Destructive size 2.5 of 5. It terminated at 4500’ elevation, or about 300 vertical feet above, and 800 lineal feet from the grade. |
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| 2022-03-07 | 22:38:00 | Path 1183 | Clark | • Ascended to the upper starting zone of Path 1183, an avalanche path named for its proximity to the railway milepost. • Objectives were to investigate the avalanche that ran within 100 yards of the rail grade last week in this path, look for other nearby avalanche activity nearby, and to assess the current snowpack conditions. | • Broken skies and occasional sunshine with no precipitation and calm winds all day. • Air temperatures reached the mid-30s °F on the Canyon floor and the mid-20s °F at 6000’ by late afternoon. | • Rock hard surface crust everywhere, 4-6+” thick, that is supportable in skis and often even in boots. On the Canyon floor there is a trace of recent snow on top of the crust and at our high point at 5900’ there’s about 5”. This snow fell late last week and has mostly turned into weak facets. • No wind-loading observed on our route and we did not see any blowing/drifting snow up high on Nyack Mtn above us. • Currently no signs of instability observed. | • No recent avalanche activity observed, but we saw multiple storm slab crowns and wet loose avalanches from last week’s impressive and widespread avalanche cycle. • The avalanche in Path 1183 likely ran sometime in the early morning hours of March 1st. o It initiated as a storm slab at the top of the path at 5700’ elevation, on a NE aspect, failing on the storm slab interface. The crown today was 1-2 feet thick and about 700’ wide (photo). Associated debris entrained a fair amount of wet debris on the way to the valley floor. o Additional wet loose avalanches ran afterwards and may have contributed to the debris pile in the runout. o This was a destructive size 2.5 with debris running 2200’ vertical feet, flowing over old US Hwy 2 and under the FEC powerlines. The debris pile was about 25’ deep at the deepest and 40-70’ wide with some small broken trees in it (photo). • Other notable avalanche activity included multiple crowns in the Cascadilla and Wahoo basins. All of these appeared to be storm slabs and up to D2 in size. • On the SE face of Triangle Ridge above Great Bear Creek, we noticed two large crowns, one running for several hundred feet (size D2.5 at least). |
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| 2022-02-17 | 18:58:00 | Burnout to Shed 7 West | Steiner | • Ascended the ridge above the Burnout, Shed 4D, Shed 5, and Shed 7 East avalanche paths. Continued south on Snowslip Mountain ridge to the starting zone of Shed 7 West. • Objectives were to look for any recent avalanche activity, assess snowpack structure and test snowpack instability at our snowpack observation location. | • Cloudy skies with light snowfall throughout the day. • Light to moderate westerly winds with occasional strong gusts at mid and upper elevations. Wind loading of available snow on easterly through northeasterly aspects above 6000 feet elevation. • Air temperatures remained below freezing at all elevations throughout the tour. Canyon floor air temperatures climbed into the low 30s °F and upper elevations reached the upper 20s °F. | • Recent wind slab development with greater that 4” thickness was observed on: o Northeasterly and easterly aspects o @ elevations above 6000’ o On slopes greater than ~35 degrees. • Wind loading of available snow for transport was observed on easterly to northeasterly aspects. • Full-depth profile conducted in the Starting Zone of Shed 7 West at ~6600 feet on an easterly aspect. Please refer to Shed 7 W Upper SZ profile for details. o Snow depth was 73” and the primary layer of concern was a layer of facets buried about 18” down that was located on top the “Mid-January” crust. o Stability Test at this location did produce one unstable result (ECTP25) on the January facets. The second Extended Column Test produced a fracture without propagation on the same layer. | • No recent avalanche activity observed. • Did not observe collapsing or audible failures during field tour. • Very localized propagation (shooting cracks) was artificially initiated by ski cuts and stomping. When initiated, resulting slab thickness varied from ~4” to ~6”. • Artificial propagation wind slab deposit occurred mainly in isolated areas that had previously been undercut (disturbed) with ski tracks and/or kick-turns a few feet below. • Attempting to initiate propagation in areas that had not been disturbed proved difficult (stubborn) and propagation did not occur. |
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| 2022-02-10 | 22:46:00 | Burnout to Shed 7 East | Clark | • Ascended the ridge above the Burnout, Shed 4D, Shed 5, and Shed 7 East avalanche paths. • Objectives were to look for any recent avalanche activity and assess snowpack structure and stability in this area. | • Partly cloudy skies with no precipitation all day. • Light to moderate westerly winds with occasional strong gusts at upper elevations. With the wet/moist snow surface there was no wind loading in our vicinity and none observed on other nearby peaks. • Very warm temperatures for this time of year with daytime highs in the low-50s °F this afternoon on the Canyon floor and the mid to high-30s above 6000’. | • Very warm temperatures had the snowpack surface wet/moist everywhere we toured today. Our high point was at about 6400’ • Minimal avalanche activity and limited signs of instability today. Ski cuts on steep slopes produced rollerballs, but no actual loose wet avalanches. The snowpack seems to be adjusting to the warm conditions of this week. • Dug three snow pits, one each in the following paths: Burnout, Shed 4D, and Shed 7 East (see pit profiles below), and a fourth pit on a NE aspect in upper Shields Creek. o The January facet/crust weak layers of concern were buried about 10-14” deep in non-wind-loaded locations, and in some instances the faceted grains were beginning to round. We had no propagating results after multiple Extended Column tests. o No buried surface hoar found on the shady slope in Shields Ck. | • One small (destructive size 1 of 5) wet loose avalanche ran at Umbrella Fence today (east aspect, 4400’ elevation). A very small amount of debris terminated right next to the grade. • No other avalanche activity observed. |
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| 2022-02-04 | 22:54:00 | Second Slide and Shed 10 | Steiner | • Toured up the “Second Slide” rock outcrop between Shed 10 and Grizzly Gulch. • Observed windloading (crossloading) in the Second Slide starting zone. • Continued up the rock-outcrop ridge past Second Slide into the upper starting zone area of Shed 10 • Observed evidence of relatively recent (past week?) avalanche activity on easterly aspects above 7000’ in the Shed 10 avalanche path. • Descended the Shed 10 path back to the Canyon floor. Objectives were to: o Observe signs of recent avalanche activity. o Observe windloading and instability associated with recent windslab formation. o Observe snowpack structure and how structure has been affected by recent cold air temperatures and additional loading due to wind and new snowfall. | • Cloudy skies and obscured conditions throughout the entire field day. • Light to moderate snowfall occurred throughout the day with perhaps ~5 cm of new snow (HNS) at Canyon floor elevations in the past 24 hours. • Moderate wind with strong gusts occurring at elevations above 5500 feet elevation. • Air temperatures were in the upper-20s to mid-30s (0F) at lower elevations (Below ~5000’) throughout the day and mid 20s (0F) at upper elevations (Above ~6000’). By late afternoon, air temperatures had climbed above freezing at Canyon floor elevations (~4400’). | • Wind transport and loading was ACTIVELY occurring on easterly aspects. This was particularly evident above 5500 feet elevation. • Approximately 2” to 4” (5cm to 10cm) new snow (HNS) in the past ~24 hours at all elevations in JFS Canyon (Canyon). • Observed approximately 25 cm of accumulated snow from this past week. • New snow from the past week was interfaced with an approximate 3 cm of buried near surface facets which were resting on older snow and/or crust interface. • New slab formation was cracking in isolated areas during ski cutting and stomping tests (photo). Cracking was not propagating out beyond the localized area where skier weight was being applied. Slab thickness varied between 4” and 10” (10 to 25 cm). | • Evidence of relatively recent (this past week?) moderate sized (Size 2 or greater) slab avalanche activity on steep and poorly anchored easterly/ southeasterly aspects above 7000 feet elevation. • Isolated cracking and very small slab activity initiated by skiing throughout today’s tour at all elevations, but particularly above 5500 feet elevation. • No audible failures and/or collapses observed. |
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| 2022-02-01 | 17:46:00 | Java East to Shed 11 | Clark | • Ascended the ridge to the west of the Shed 11 avalanche path to the weather station at 6400’ elevation. Descended the same route. • Objectives were to observe recent snowfall totals and the extent of recent wind-loading, look for any avalanche activity, and assess snowpack structure and stability in this area. | • Overcast or obscured skies with on again/off again periods of snowfall with intensities up to S1. • Light to moderate easterly winds with occasional strong gusts at all elevations. • Air temperatures have been dropping all day. As of 1700 they range from -3 to 3 °F on the Canyon floor and -15 to -11 °F at weather stations above 6000’. | • Overnight snow totals ranged from 2-3” on the Canyon floor, another 1-2” of snow fell throughout the day. • The advertised arctic air arrived by mid-morning. Winds clocked to the E-NE and were blowing at moderate intensities and actively loading westerly aspects at all elevations. These fresh wind slabs were ~10-15” thick by mid-afternoon. • In areas sheltered from the wind, the new snow is not cohesive enough to form a slab yet and here we found no signs of instability. • Ski cuts in the new wind slabs on westerly aspects resulted in some shooting cracks (3-5’ long) and some very small slab releases. Ski cuts on easterly aspects (older wind slabs) were mostly unreactive to ski cuts with only slight cracking, 1-2’ long. • Dug a hasty snow pit in the upper starting zone of the Shed 11 avalanche path at 6400’ on a southerly aspect. Snow depth was 70” with about a foot of new snow from the storm accumulated on crust/facet/crust layer sandwich (pit profile below). No propagating fractures with an Extended Column Test. | • No avalanche activity observed, but visibility was very limited all day. | |
| 2022-01-31 | 20:54:00 | Burnout to Shed 7 | Clark | • Ascended the ridge above the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths. Descended Shed 4D and Shed 5. • Objectives were to observe recent snowfall totals and the extent of recent wind-loading, look for any avalanche activity, and assess snowpack structure and stability in this area. | • Overcast skies with on again/off again periods of snowfall with intensities up to S2. • Light westerly winds on the Canyon floor with light to moderate winds above 5000’. • Around 1630 winds were beginning to clock around to the N-NE and the temperature was dropping. • Daytime high air temperature reached the high-20s °F on the Canyon floor and the mid-teens °F at upper elevations. | • Overnight snow totals ranged from 3-5” (with 0.31-0.38” water equivalent) on the Canyon floor and 6-10” above 6000’. Another 2-4” of snow fell throughout the day. • Wind-loading has been heavy above 5000’ elevation due to moderate to strong westerly winds. New wind slabs were 10-18” thick, but stubborn to triggers with limited shooting cracks. • In areas sheltered from the wind, the new snow is not cohesive enough to form a slab yet and here we found no signs of instability. • The new snow is accumulating on a layer of near-surface faceted grains and in some shady and sheltered locations, surface hoar. • Dug a hasty snow pit in the upper starting zone of the Shed 4D avalanche path at 5800’ on an easterly aspect. Snow depth was 69” with about a foot of new snow from the storm accumulated on a layer of facets above the mid-January crust. (pit profile below). No propagating fractures with an Extended Column Test. | • One small, natural triggered, destructive size 1 of 5 slab avalanche observed just below the Shed 6/7 ridge. The crown appeared to be about 10” thick and 20-30’ wide. Debris terminated well above the grade. • Ski cut triggered a small destructive size 1 slab on the ridge east of Shed 5. Crown was 5-10” thick and 20’ wide. • No other avalanche activity observed, but visibility of the surrounding terrain was very limited. |
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| 2022-01-24 | 17:30:00 | Burnout to Shed 4D | Steiner | • Ascended the Burnout ridge to above Shed 4 and then worked back toward Burnout. • Objectives were to observe recent avalanche activity and examine snowpack structure at low to low/moderate starting zone elevations on the Program Area. • Also conducted a welfare check on Shed 4 Weather Station. Was able to free up support cables for wind sensor mast. Good timing as cables were pulling mast off center due to snowpack settlement. | • Overcast conditions with light to moderate snowfall between 1100 and 1500. Calm conditions with light gusts of westerly wind. • Light SW winds with occasional moderate gusts in exposed terrain above 6000’. Wind-loading observed during the tour was minimal. • Daytime high air temperature reached 30 °F on the Canyon floor and the mid-20s °F at upper elevations. | • Up to 2 cm new, low density, snowfall accumulation throughout today on the east end of the Program Area at Canyon floor elevation. Only a trace of new snowfall measured at Java (West end). • Snowpack observations on a 35-degree SE aspect at 5295’ a.s.l. included a full-depth profile and one (1) ECT stability test. • No significant results in ECT. Snowpack at this location was 90 cm in depth. o 90-75 cm= Three (3) layers of precipitation particles (new snow grains) (~2.0mm). F. o 75-65 cm= Decomposing Melt-Freeze Crust. 1F- o 65-60 cm= Melt-Freeze Crust. 1F+ o 60-40 cm= Mixed Forms (1.5mm) 1F o 40-00 cm= Rounds. (1.5mm) 1F+ • Some faceted snow was observed below the 65-60 MF crust but did not yield significant results in ECT test. | • No avalanche activity observed throughout the day and no obvious signs of snowpack instability observed while on tour. | |
| 2022-01-21 | 22:25:00 | Shed 7 to Shed 9 | Clark | • Ascended the ridge east of the Shed 7 East avalanche path, then toured on into Shed 7 West, and further into the Shed 9 path. • Objectives were to observe snowfall totals and the extent of recent wind-loading, look for any new avalanche activity, assess the snowpack structure and stability in these paths, and make a welfare check on the Snowslip weather station. | • Broken skies with no precipitation and calm winds on the Canyon floor. • Light SW winds with occasional moderate gusts in exposed terrain above 6000’. Wind-loading observed during the tour was minimal. • Daytime high air temperatures reached the low to mid-30s °F on the Canyon floor and the mid-20s °F at upper elevations | • Snowfall totals on the Canyon floor from yesterday’s storm were deepest at the western end with 6” at Essex, 3” at Java East, and only 1.5” at Devil Creek. Total liquid water for the storm ranged from 0.25”-0.36” on the Canyon floor. • Above 6000’ elevation yesterday’s snowfall totals ranged from 8-10”. New wind slabs had formed on easterly aspects, primarily above 5500’ and were about 10-18” thick. Ski cuts in these new slabs resulted in only minor cracking (photo). • The mid-January crust is widespread across the Program Area and was found up to 7000’ on slopes above the rail. Some weak faceted snow was observed below this crust which proved reactive in some stability tests. • Dug first snow pit at 5400’ on a wind-loaded easterly aspect. Snow depth was 53” and composed mostly of 1F hardness. Mid-Jan. crust was 2” thick with 6” new snow of top. Extended Column Test yielded ECTX. No notable weak layers found. • Second snow pit in the Shed 7 West path at 6600’ and east aspect. Snow depth was 77” with 12” of new snow resting on top of the ½” thick mid-Jan. crust. First Extended Column Test yielded ECTP17 on a thin layer of facets below said crust. Repeated the test and ECTN14 at same depth. CT14 Q2 on same layer of facets. No other fractures or notable weak layers found. • Third snow pit in the Shed 9 path at 6800’ on SE aspect. Snow depth was 45”, but this was a more scoured location. About 8” of snow from yesterday on top of the ½” thick mid-Jan. crust. ECTN17 on a thin layer of facets under the crust. Found a 2” thick layer of older rounding facets that was 27” down from the surface, CT15 Q2 on this layer. | • No avalanche activity observed in the immediate vicinity. The Shed 7 paths have not produced any large avalanches yet this season. • Visibility of distant terrain was fair, and no avalanche activity was observed in the nearby Flathead Range or on other Peaks in the Park. |
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| 2022-01-09 | 18:52:00 | Second Slide | Clark | • Visited the crown of the Second Slide avalanche that ran in the night on Jan. 7th/8th. • Objectives were to size up the crown in Second Slide and obtain a profile of the snowpack there. Also went to look for additional avalanche activity, observe the recent wind-loading, and assess snowpack stability. | • Mostly sunny skies with no precipitation and light to moderate westerly winds. • Daytime high air temperatures reached the mid-30s °F on the Canyon floor and the low to mid-20s °F at upper elevations | • Our most recent rain crust from the Jan 7th/8th storm is present on the snowpack surface from the Canyon floor up to about 4600’ elevation. • A layer of buried facets was widespread during our tour. Below 5000’ these facets were resting on top of the mid-Dec. crust. Above this elevation, no crust was present near the facet layer. • The wind-loading from the recent storm was impressive with slabs 1-4’ thick. We cut several of these recent wind slabs and had mostly unreactive results – no cracking or whumpfing, but some collapsing into the facets at lower elevations. | • The avalanche in Second Slide ran sometime around 0030 hours on Jan. 8th. Debris was deposited on the grade and was 6-15’ deep and 60’ wide - a Destructive size 2 of 5 o This avalanche initiated in the uppermost starting zone at 5400’ on a SE aspect. o The crown was about 300’ wide, 1-3’ thick, and already partially filled back in with wind-transported snow (photo). o This was a wind slab that formed from the recent westerly winds and about 1-finger hardness. It failed on a layer of buried facets (see crown profile). o An extended column test did not yield any fractures on the avalanche failure layer, but a compression test resulted in CT14 Q3 on said layer. • We encountered another avalanche on our descent on an easterly aspect at about 5200’. Another wind slab that likely failed on the same layer of buried facets. This was also a Destructive size 2 of 5 and associated debris ran several hundred feet through thick trees terminating well-above the rail grade. |
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| 2022-01-06 | 22:14:00 | Canyon Obs and Burnout to Shed 7 ski tour | Clark | • Visited the manual weather stations this morning and evening and toured above the Burnout, Sheds 4D, 5, and 7 avalanche paths. • Objectives were to look for avalanche activity, observe recent snowfall totals and wind-loading, and look at the snowpack structure in the Burnout path. | • An overrunning scenario today with temperatures in the single digits °F on the Canyon floor and in the mid-teens °F above 6000’ this afternoon. At 2200 temperatures above 6000’ have risen to the low-20s °F. • Westerly winds picked up at ridgetop locations by early afternoon, reaching moderate speeds and were actively transporting snow. • Snowfall rates picked up considerably after 1700 today and have reached S2-S5 intensities this evening. | • As of 2000, snowfall totals for the current storm on the Canyon floor stand at 3-4” with 0.31-0.39” of water. • Moderate westerly winds were forming fresh wind slabs, 4-12” thick above 6000’. Ski cuts produced some minor cracking (2-4’ long), but no slab releases. • On slopes exposed to the easterly winds during the past week, there was firm wind-packed snow underneath the few inches of powder from the past 24 hours. In some locations this wind board was supportable even in boots. • Dug a snow pit at 5200’ elevation in the Burnout path on an easterly aspect. Snow depth was 39” with a layer of faceted snow buried about a foot deep, CT15, Q2 and ECTN19 on this layer. The Dec. 18th crust was not present here. | • No avalanche activity observed. | |
| 2022-01-04 | 16:28:00 | Road Obs from Hwy and Java Gauntlet | Clark | • Windshield observations from Hwy 2 and then visited the Java Gauntlet avalanche path. • Objectives were to look for avalanche activity, observe recent snowfall totals and wind-loading, and investigate snowpack structure and stability in the Gauntlet. | • Another push of Arctic air came over the Divide last night. Air temperatures on the Canyon floor dropped from near freezing to as low as -10 °F by sunrise today. Winds clocked from the west to the E-NE and increased in speeds. • Today we had overcast with occasional broken skies and on again/off again flurries of snow and graupel mixed. • Winds above 6000’ remained predominantly from the west, mostly light, but with moderate gusts. | • Overnight snowfall on the Canyon floor totaled 2-4”. Weather stations above 6000’ are reporting 4-6” • Moderate easterly winds were channeling down the Canyon forming fresh wind slabs on the Canyon floor. • A snowpit dug at 4100’ elevation at the eastern end of Java Gauntlet, NE aspect, 30° slope. Snow depth was 35”. Most notable are layers of weak faceted snow above/below the December 18th crust, now buried about. Poor structure but no propagating results today with an Extended Column test (see pit profile below). | • No avalanche activity observed save for two very small (3-6” thick and 3-6’ wide) intentionally triggered wind slabs in the Gauntlet. Associated debris ran only a few feet and terminated well above the grade. | |
| 2021-12-29 | 23:16:00 | Sheds 11 and 10.7 and Path 1163 | Clark | • Toured up the Shed 10.7 ridge to the Shed 11 weather station at 6400’, then further up to the top of Path 1163 at 7200’. • Objectives were to look for avalanche activity, observe recent snowfall totals and wind-loading, and investigate snowpack stability in this area. | • Partly cloudy until about late morning, then broken skies with some clouds below ridges/ in valleys. No precipitation throughout the day. • Air temperature was -6° F at highway at 10 AM, then 3° F at 4 PM. • Calm with occasional light gusts on southerly slopes, winds light to moderate at ridgeline, from west-northwest. Light blowing snow near ridges. | • The weakest snow is at low elevations (below 5000 feet). A layer of soft facets is sandwiched by a 4-finger slab above and a hard rain crust from Dec. 18th below. This structure cracked at switchback corners. This structure may persist and prove problematic when loaded in the future. • The snowpack on mid to upper-elevations slopes was mostly right-side up (progressively harder with depth), save for some areas with wind slabs. There were no evident buried weak layers. • A snowpit dug at 5200 on a south aspect revealed a snow depth of 30” with no propagating results during Extended Column Test. • A second snowpit dug at 6400’ on a south aspect in the Shed 11 path showed a snow depth of 47” with no obvious weak layers save for a layer of buried graupel 16” below the surface. ECTN 24 on this layer. | • Intentionally triggered a couple small (Destructive size 1 of 5) wind slabs on safe test slopes on wind-loaded terrain above 5500’. • No natural slab avalanche activity observed in Path 1163 or Sheds 10.7 or 11. |
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| 2021-12-26 | 19:57:00 | Program Area from the Hwy | Clark | • Objectives were to look for avalanche activity, observe recent snowfall totals and wind-loading, and check the manual weather stations on the Canyon floor. | • Frigid and windy! Temperatures today on the Canyon floor ranged from -15 to -7 °F and were accompanied by moderate easterly winds causing plenty of blowing and drifting snow. • Temperatures above 6000’ have plummeted below -20 °F. • Occasional flurries this afternoon/evening with periods of clearing skies. | • Moderate NE winds have been actively wind-loading terrain at all elevations since last night. • The Canyon floor accumulated 5-6” of snow with 0.55” of water equivalent over the past 48 hours. | • Observed one avalanche in the Infinity path (MP 1160.5) that likely ran sometime early this morning. Estimate the crown was 150’ wide and 1’ thick. It was located at 6000’ elevation on a southerly aspect. Associated debris ran to about 4600’ terminating above the grade. This was a destructive size 2 of 5 and likely a wind slab formed by the recent NE winds. • No other avalanche activity observed or reported. |
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| 2021-12-22 | 17:42:00 | Burnout to Shed 7 West | Clark | • Climbed the SE ridge of Snowslip Mtn. to 6800’ elevation observing conditions in the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths. Descended Shed 5. • Objectives were to observe recent snowfall totals and the extent of recent wind-loading, look for recent avalanche activity, and look closely at snowpack structure in Shed 7 West. | • Observed 2 small (Destructive-size 1.5 of 5) wind slab avalanches that had recently released in the Shed 7 W path this morning. Associated debris terminated well above the rail grade. | • Moderate to strong westerly winds were forming new wind slabs on easterly aspects above 5000’ elevation. • Experienced some minor shooting cracks, 4-6’ long in these most recent wind slabs. • 3-4” of new snow since Monday (12/20) on the Canyon floor with 3-5” above 6000’. • Dug a hasty pit in the Shed 7 west path at 6600’, east aspect, snow depth was 46” with a right-side up snowpack except a layer of rounding facets near the ground resting on top of a melt freeze crust. ECTN21 @31” on a density change w/in some wind slabs and CT19 Q2 on this same layer. CT28 Q3 at 2” on the layer of rounding facets. • Dug a hasty pit on a NE aspect at 6700”, snow depth 78”. ECTP8 and 4 about 12” below the surface on a layer of very soft (F-) powder (DFs) immediately beneath a 4” thick wind slab at 1F hardness. | • Overcast skies with snowfall and graupel showers all day (S-1 to S1). Windy in the morning with moderate, mostly westerly winds at all elevations. Around mid-day winds became light on the Canyon floor, but remained elevated above 5000’. • About 1” of graupel fell during the day. • Daytime high temperatures reached the low to mid-30s °F on the Canyon floor and the low to mid-20s °F above 6000’. |
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| 2021-12-18 | 23:13:00 | Burnout to Shed 7 | Clark | • Climbed the SE ridge of Snowslip Mtn. to 6500’ elevation observing conditions in the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths. Descended the same route. • Objectives were to observe recent snowfall totals and the extent of recent wind-loading, look for recent avalanche activity, and check out snowpack structure and stability in this area. | • Overcast skies with snowfall (S-1 to S2), and moderate to strong westerly winds. Another 1-3” of snow fell before nightfall. • Temperatures have warmed rapidly this evening and reached above freezing at 2200. Snow changing to rain on the Canyon floor. | • Moderate to heavy wind-loading occurring at all elevations today from moderate to strong westerly winds. • Wind-loading was most pronounced above 6000’ with new slabs 2-3’ thick since Thursday (12/16). • Experienced one audible collapse and shooting cracks (10-20’ long) at 6300’ on a SE aspect slope near the Shed 7 East avalanche path. • Dug a hasty pit in the Burnout path at 5300’, east aspect, snow depth was 26”. There was a layer of rounding facets 4” above the ground resting on top of melt freeze crust. ECTN25 and CT25 Q2 on this layer. Otherwise right side up layering and no other notable fractures. • Dug a hasty pit in the Shed 4D path at 5900’, SE aspect, snow depth 37”. ECTN23 and CT22 Q2 on a layer of buried graupel at 18”. Otherwise right side up layering and no other notable fractures. | • No avalanche activity observed but visibility was limited by clouds and snowfall. | |
| 2021-12-16 | 22:15:00 | Sheds 7 and 5 | Clark | • Climbed the ridge dividing the Shed 6 and Shed 7 avalanche paths to the Shed 7 weather station at 6300’. Descended the Shed 5 path. • Objectives were to observe recent snowfall totals and the extent of recent wind-loading, look for recent avalanche activity, and complete a snowpack profile in Shed 7. | • Overcast skies with snowfall (S-1 to S2), and moderate westerly winds above 5000’ with calm or light winds on the Canyon floor. Another 1” of low-density snow today fell today. • Daytime highs reached the low-20s °F on the Canyon floor and the mid-teens °F above 6000’ elevation. | • Snow depths are building quickly with a settled base of 15-20” on the Canyon floor and 2-4’ at elevations above 6000’. • Active wind-loading above 5000’ elevation due to moderate westerly winds with fresh wind slabs building, primarily on easterly aspects. In addition to the above-mentioned avalanche, observed a few shooting cracks 5-20’ long in these fresh wind slabs. • Dug a snow pit at 6350’ on an east aspect near the top of the Shed 7 East avalanche path. Total snow depth was 45” consisting of right-side up layering until a layer of rounding facets near the ground resting on top of an 8” thick laminate of alternating layers of crusts and facets (snow profile). No propagating fractures with an Extended Column Test. | • Intentionally triggered a small wind-slab in Test Slope 3 at 5600’ on a SE aspect, SS-AS-D1.5-R3-I. Crown was about 30’ wide and 4” to 12” thick (photo). Debris ran about 100’ terminating well above the grade. • No other avalanche activity observed. |
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| 2021-12-06 | 21:58:00 | Shed 11 to Path 1163 | Clark | • Climbed the ridge dividing the Shed 11 and Shed 10.7 avalanche paths to the Shed 11 weather station and continued up to the starting zone of Path 1163. • Objectives were to observe recent snowfall totals and assess snowpack stability, look for any recent avalanche activity, and conduct repairs on the weather station. | • Overcast skies with snowfall (S-1 to S2), and light westerly winds. Another 3-5” of low-density snow today fell today. • Daytime highs reached the low-20s °F on the Canyon floor and ranged between 10-15 °F above 6000’ elevation. | • 6-8” of snow accumulated on the Canyon floor during the Dec. 4th storm with about 12-18” above 6000’ elevation. • Wind transport and loading had occurred at elevations above 5000’, primarily on easterly aspects. Post-holing across several recent wind pillowed test slopes resulted in no cracking or slab releases. • Very little wind-loading today and no other signs of instability observed. • Before Dec. 4th most of the Program Area was snow free below 6000’ with scattered, dis-connected patches of older snow consisting of melt-freeze crusts and some faceted layers above this elevation. • Dug one hasty pit at 7100’ on a south aspect on the ridge between Path 1163 and the Shed 10.7 path. The top 14” was low-density powder snow from last weekend’s storm. This was resting on top of 7” of old snow consisting of alternating layers of rain/melt freeze crusts and rounding facets. Extended Column Test yielded ECTN25 just below the uppermost crust located 15” below the surface. | • Observed a few small (destructive size 1 of 5) dry loose sluffs in Path 1163. Associated debris terminated well above the grade. • No other avalanche activity observed. |
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| 2021-04-06 | 22:21:00 | Burnout to Shed 11 - Program Area traverse | Clark | • Climbed up the Burnout avalanche path at the eastern end of the Program Area and made a high traverse to the western end of the Program Area and descended the Shed 11/10.7 ridge. • Objectives were to: observe any signs of recent avalanche activity, assess snow surface conditions, and conduct repairs on a couple remote weather stations. | • Clear skies, full sunshine, and light westerly winds all day. • Overnight lows dropped to the mid-20s °F, daytime highs reached the low-50s °F on the Canyon floor and the high-30s to low-40s above 6000’ elevation. | • Recent wind transport and loading had occurred at elevations above 6000’. Minor cracking in some isolated, shallow wind slabs. No active wind loading. • No other signs of instability observed. • Approximately 1-2” new snow yesterday at elevations above 6000’. No new snow below that. • Snow surfaces that had melted yesterday and re-frozen last night had softened by mid to late -morning on solar aspects. • The snowpack below 5000’ in the Program Area has mostly melted out. | • No recent avalanche activity observed. • Noted a glide crack forming about half-way down slope in Path 1163. |
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| 2021-03-30 | 23:30:00 | Shed 7 | Steiner | • Toured up the “Shed 7” avalanche path to the confluence of Shed 7 East and West. • Followed old debris flow up the Shed 7 East path to approximately 5800’ a.s.l. • Continued uphill travel to the terrain just above the starting zone of Shed 7 East. • Descended to the Shed 7 Weather Station and continued down to the rail grade. Objectives were to: o Observe any signs of recent avalanche activity. o Assess snow surface conditions. o Conduct any needed repairs on Shed 7 Weather Station. | • Partly cloudy skies the entire field day with snow squalls in the area. • No new snow accumulation throughout the day. • Air temperatures were in the mid-20s (F) at lower elevations (Below ~5400’) during morning hours and upper 20s (F) at upper elevations (Above ~6000’) during early afternoon. By late afternoon, air temperatures were above freezing at Canyon floor elevations (~4400’). | • Wind transport and loading has PREVIOUSLY occurred at ridgeline elevation(s). No active wind loading. • The Shed 7 West cornice has grown quite large again over the past month (photo). • Approximately 2” to 4” (5cm to 10cm) new snow (HNS) in the past ~24 hours at all elevations in JFS Canyon (Canyon). • New snow was interfaced with previously-formed and stout melt-freeze crust. • Melt-freeze crust softened up by late afternoon at elevations below • A surface sun crust was beginning to form during the afternoon hours at elevations above ~6000’ • Below ~6000 feet, surface snow (new snow) had become moist and transitioned to wet below ~5400’. Melt-freeze crust also softened substantially at elevations below ~5400’ | • No recent avalanche activity observed. • No noticeable cracking of the snowpack surface, • No audible failures and/or collapses observed. |
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| 2021-03-17 | 19:13:00 | Shed 7 to Grizzly Gulch to I-Beam | Clark | • Long tour through much of the high elevation terrain of Program Area with objectives to investigate some older avalanche activity, look for any recent avalanche activity, and assess snowpack stability in this area. | • Clear skies with no precipitation all day. Calm to light westerly winds at all elevations. • Daytime highs reached the mid-50s °F on the Canyon floor and the mid-40s to high 30s °F at terrain above 6000’. | • Variety of snow surface conditions depending on elevation, aspect, and time of day. Very firm and frozen conditions leaving the rail at 0830, ski crampons were helpful. But slopes in the sun began to soften a couple hours later providing some better snow surface conditions later in the day. • Shady slopes above 6000’ still held some cold dry snow. • No signs of instability observed during the tour, no cracking, collapsing, or rollerball activity. • The snowpack is melting quickly on sunny slopes at elevations below 5000’. Some low elevation paths above the rail such as Second Slide and Jakes have very little snow left in them. | • Observed and photographed the two large avalanches that ran during the 3rd week of February. The vegetation damage was impressive. In the Shed 7 West path limbs were broken off trees over 30’ up the trunk. Many other trees were uprooted or snapped in both Shed 7 West and Shed 7 East and then carried several hundred feet down the slope (photo). • Noticed a large glide avalanche outside the Program Area that ran on the south face of Rampage Mountain. Date of occurrence unknown and at least D2-sized. • No other recent avalanche activity observed. |
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| 2021-03-12 | 23:00:00 | Sheds 11, 10.7, Path 1163, I-Beam | Clark | • Long tour on the western end of the Program Area with objectives to investigate some older avalanche activity, look for any recent avalanche activity, and assess snowpack stability in this area. | • Clear skies with no precipitation all day. Calm to light westerly winds at all elevations. • Daytime highs reached the mid-40s °F on the Canyon floor and mid-30s °F at elevations above 6000’. | • Variety of snow surface conditions depending on elevation, aspect, and time of day. Most notable was a healthy crop of surface hoar found on sheltered, shaded aspects which seemed to be confined to elevations above 6000’. • Dug a pit at 6900’ on a southerly aspect near the Shed 10.7 starting zone and at a location where the mid-Jan. facets were reactive and propagating during stability tests a month ago. An extended column test resulted in ECTX. A Deep Tap test targeting the mid-Jan. facets (buried ~3’ down) resulted in DT21, Resistant Planar fracture. • Other than the falling cornice event mentioned above, no other signs of instability observed during the tour: no cracking, collapsing, or rollerball activity. | • Excellent views of the surrounding terrain all day. Noticed a crown on the north face of Unawah Mtn. Date of occurrence unknown, likely sometime during the last week, estimate about D2-size. • Remotely and unintentionally triggered a large cornice fall from a safe location while skinning along a ridgeline at 7400’. Cornice chunk was approx. 20’ wide by 15’ tall and was overhanging an east-facing slope. No slab released when the chunks thumped the snow slope about 200’ below. • No other recent avalanche activity observed. • Visited the crown of a large avalanche (previously reported) that ran a week ago on the west face of Running Rabbit Mtn. in a path known as I-Beam. We inspected the crown (photo) at about 7400’ and no Jan. 13th crust present at this elevation. But the failure layer of this large hard slab was the mid-Jan. facets. |
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| 2021-03-11 | 17:18:00 | Second Slide | Clark | • Climbed into the upper starting zone of an avalanche path known as Second Slide to a high point at about 5700’ elevation. • Objectives were to investigate the avalanche that ran in this path on the night of Feb. 21st. Also, wanted to observe snow surface conditions and look for any recent avalanche activity in this vicinity and the surrounding terrain. | • Mostly clear skies with no precipitation all day. Light westerly winds on the Canyon floor and moderate west-southwest winds above 5000’ elevation. • Daytime highs reached the 40s °F on the Canyon floor and just below freezing °F at elevations above 6000’. | • Sunny aspects had softened by the time I was on them in late morning. Shady aspects held breakable crust. • No signs of instability during the tour, no cracking, collapsing, or rollerball activity. | • No crown for the avalanche in Second Slide could be found on the morning after it ran (Feb. 22nd) and could not find any remnants of one today either. However, by following signs of vegetation damage and debris piled on the uphill sides of trees, it was determined that this avalanche initiated in the bowl at the very top of the path and just below the prominent rock outcrop situated above the slope. This avalanche was a destructive size 2 of 5 that ran about 1200 vertical feet, terminating at the rail grade. • No recent avalanche activity was observed while on the ski tour. • From the Hwy, noticed some recent cornice fall in Shed 7 West and most notably a fresh crown on the SE face of Cameahwait (outside the Program Area). The Cameahwait slide looked about D2.5 size and possibly cornice fall triggered. |
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| 2021-03-04 | 20:30:00 | Burnout to Shed 9 | Clark | • Toured above several avalanche paths today: Burnout, Shed 4D, Shed 5, Shed 7, and Shed 9 to a high point at the Snowslip weather station at about 7000’ elevation. • Objectives were to look for recent avalanche activity, observe snow surface conditions, repeat stability tests in the Burnout avalanche path, and perform maintenance on weather stations. | • Completely clear skies with calm or light westerly winds above 6000’. • Daytime highs reached near 60 °F on the Canyon floor and into the 40s °F at elevations above 6000’ – very warm for this time of year. | • Wet snow on sunny aspects at all elevations and even on shady aspects below about 5500’. Some cold, dry snow hanging on the shady aspects above 5500’. • Repeated Extended Column Tests (ECT) in the same snowpit visited on Feb 28th near the Burnout path at 5150’ elevation, easterly aspect. ECTP 21 and 23 on weak faceted snow near the Jan. 13th crust about 35” down from the surface. | • Widespread, small (destructive size 1 of 5 – D1) wet loose avalanches have been observed throughout the Program Area and in surrounding terrain. Debris either terminated above the grade or was too small to be of concern. • A small (D1.5) slab ran in Jakes yesterday (RR MP 1161.9). Debris terminated above the grade. • Cornice fall in Shed 7 West, associated debris did not trigger a slab avalanche underneath the cornice. • A ~D2-sized crown was observed across the valley on an unnamed summit above the Devil and Grizzly Creek drainages. Estimate that this ran sometime yesterday. • Most notable was a very large (D3) avalanche that ran this afternoon in a path known as I-Beam (photos). This path is located outside the Program Area and does not threaten the Railway. It does threaten US Hwy 2 and is located on the west face of Running Rabbit Mountain. At this time it is uncertain where in the path the debris terminated, but it did not reach the highway. |
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| 2021-02-28 | 22:49:00 | Burnout | Steiner | • Toured up adjacent terrain to the avalanche-prone slope referred to as “Burnout.” • The name Burnout refers to what remains of Snowshed 4C. 4C burned down in 1978 from an equipment-malfunction fire (a spark) on the Railway grade. • Surface snow conditions in this terrain feature consisted of ~40” of accumulated snowfall on the January 13th crust/facet interface. Objectives were to: o Observe snowpack instability at Burnout SZ elevation. o Assess snow surface conditions. o Conduct a snow profile and stability tests in non-avalanche-prone terrain adjacent to the Burnout starting zone with a similar aspect but lower slope angle. | • Overcast skies with light snowfall the entire field day. • Snowfall accumulations throughout the day amounted to a trace at best. • Air temperatures were in the mid-20s (°F) at lower elevations and upper-teens (°F) at upper elevations. | • Wind transport and loading occurring at all elevations onto easterly and northeasterly aspects. • Total snow depths around 5000’ elevation averaged 5-6’. • Snow profile at this location (5150’) revealed a 65-75” deep snowpack. Three (3) main layer interfaces were observed: o ~14” from surface- Graupel. ECTN12, ECTN 15 o ~24” from surface- Rounding Surface Hoar (no fracture) o ~40” from surface- Jan. 13th crust/ facet interface. ECTP18, ECTP19. o The Jan. crust/facet interface is currently our greatest layer of concern. | • No recent avalanche activity observed. • No noticeable cracking of the snowpack surface, • No audible failures and/or collapses observed. |
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| 2021-02-25 | 22:47:00 | Burnout to Shed 7 | Clark | • Ascended the ridge above the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths. Descended the Shed 5 path. • Objectives were to check out the crowns from the recent avalanches in Shed 7, assess the wind-loading, and assess the snowpack structure and stability in this area with special attention paid to the weak layers associated with the Jan. 13th crust. | • Full on storm day with obscured skies, snow (S2) at times, and moderate to strong westerly winds above 5500’. • Daytime high air temperatures reached the mid-20s °F on the Canyon floor and the mid-teens °F above 6000’. | • Moderate to strong SW winds were heavily loading easterly aspects above 5500’. Ski cuts on small test slopes resulted in some minor cracking and little 3-4’ slabs. In some locations new wind slabs were nearing 3’ feet thick. • No audible collapses or any other signs of instability observed. • Dug a hasty pit and performed two Extended Column Tests (ECT) in the Burnout path at around 5000’ elevation on an easterly aspect. Snow depth was 52” and the Jan. crust was buried about 30” down. ECTP26 on a layer of weak facets above the crust. • A crust from Tuesday, Feb. 22nd was present on the Canyon floor up to around 4800-4900’ elevation. | • Made it to the crown of the large hard slab avalanche (destructive size 3 of 5 – D3) in Shed 7 east which was about 2-4’ thick at this location with a slope angle of about 30°. The failure layer for this avalanche was indeed a layer of facets above the Jan. 13 crust (details in pit profile). • The large hard slab avalanche (D3) in Shed 7 West was likely triggered by a falling cornice. The crown ranged from 2-5 feet thick and it appeared that much of the overhanging part of the cornice above the crown failed as well. Again, the failure layer was a layer of facets above the Jan. 13 crust. |
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| 2021-02-19 | 21:08:00 | Burnout to Shed 7 East | Clark | • Ascended the ridge above the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths. Descended the Shed 5 path. • Objectives were to look for any avalanche activity, monitor the recent wind-loading, and assess the snowpack structure and stability in this area with special attention paid to the weak layers associated with the Jan. 13th crust. | • A mostly cloudy day but with occasional breaks to blue sky for a few minutes. On again/off again snow showers with about 1” accumulation by the end of the day. • Light SW winds on the Canyon floor and moderate SW winds with occasional strong gusts above 6000’ elevation. • Daytime high air temperatures reached the mid-30s °F on the Canyon floor and the high-teens to low-20s °F above 6000’. | • Light to moderate SW winds were actively loading easterly aspects above 5500’. Ski cuts on small test slopes resulted in some very minor cracking but with no slab releases. • No audible collapses or any other signs of instability observed. • Re-visited the Feb. 5th snowpit site in uppermost Shed 4D at 5800’ on an easterly aspect. The Jan. 13th crust is buried 32” from the surface. The layer of facets immediately below the crust that was propagating during stability tests on the 5th was unreactive today during an Extended Column Test (ECT). A compression test yielded CT22 Q2 on this layer. • Also re-visited another snowpit location at 6400’ on a NE aspect where on Feb. 5th we found a reactive layer of buried surface hoar just above the Jan. 13th crust. The crust is now buried about 30” down. ECTN30 and CT30 Q2 on the surface hoar just above the crust. | • No avalanche activity observed. | |
| 2021-02-16 | 18:31:00 | Shed 11, Shed 10.7, Path 1163 | Clark | • Toured on the ridge separating the Shed 11 and Shed 10.7 avalanche paths to the Shed 11 weather station, then continued to the uppermost starting zone of Path 1163. Kept on the ridgeline and mostly out of avalanche terrain. Descended the skin track. • Objectives were to look for avalanche activity and assess the snowpack structure and stability in this area. | • A mostly cloudy day but with occasional breaks to blue sky for a few minutes. On again/off again snow showers with about 1” accumulation by the end of the day. • Mostly calm or very light westerly winds all day. • Daytime high air temperatures reached the mid-20s °F on the Canyon floor and the mid-teens °F above 6000’. | • The poor snowpack structure associated with the Jan. 13th crust(s) persists. We had two audible collapses on southerly aspects on terrain above 6500’. One was very loud and we could feel the snowpack drop beneath us. • Dug our first snow pit below the weather station at 6400’, south aspect. HS=65” and the Jan. 13 crust was 22” down from the surface. Propagation on the first Extended Column Test, ECTP25 on a layer of facets just below the crust. ECTN24 on the same layer with the next test. • Second snow pit was adjacent to the slope with the loud collapse, SSE aspect 6850’. HS=79” and the Jan. 13th crust was about 26” down from the surface. ECTN26 on a layer of facets just below the crust, compression test yielded CT24, Sudden Planar on same layer. Second ECT we had propagation on said layer at 24 taps. • The Jan. 13th crust disappears just above 7000’. • Below 6000’ the near-surface snowpack generally consists of facets about 6-12” deep on top the Jan. 13th crust, interspersed with areas of dense wind slabs 1-2’ thick (or more) on westerly aspects. • On easterly aspects exposed to the wind, many slopes had been scoured down to the Jan. 13 crust with only a couple inches of powder from last night resting on top. | • No recent avalanche activity observed. | |
| 2021-02-05 | 17:31:00 | Burnout to Shed 7 | Clark | • Toured on the ridge above the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths. Kept on the ridgeline and out of avalanche terrain. Descended the skin track. • Objectives were to observe the recent snowfall totals and any recent wind-loading, look for any recent avalanche activity, and assess the snowpack structure and stability in this area. | • A mostly cloudy, day with occasional fog. Very little precipitation during the tour, but snowfall picked up quickly around 1800 as the forecasted arctic air began to infiltrate JFS Canyon. • Mostly calm or very light SW winds at all elevations until about 1600 when winds clocked to the north and increased substantially. • Air temperatures hovered around freezing at 1600 but had dropped to the single digits °F only a couple hours later. Temperatures above 6000’ also dropped rapidly and reached sub-zero values by the night. | • Overnight snowfall totals ranged from 5-8” with minimal wind-loading until the end of the day. • Dug in uppermost Shed 4D at 5800’ on an easterly aspect. Here the Jan. 13th crust is a “crust sandwich with some reactive facets below the uppermost crust. ECTP 13 and 18 on this layer and PST 30/110 END. There is about 18” slab on top of this layer. • Second pit was on a NE aspect at 6400’. Here there was a layer of buried surface hoar just above the Jan. 13th crust which is a stouter, singular crust at this point. ECTP 22 and 13 on this layer and PST 45/102 END. This was also the failure layer for the avalanches mentioned above. • The Jan. 13th crust disappears just above 7000’. | • No avalanches observed inside the Program Area. However, on the opposite side of the ridge, just outside the Program Area we were able to remotely trigger 4 avalanches. These were all about destructive size 2 in size and were failing on a layer of buried surface hoar above the Jan. 13th crust. • We also turned around at one point and noticed that an entire bowl in upper Shields Creek had slid. This avalanche was a Destructive size 3 and also appeared to have failed on the same buried surface hoar layer. |
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| 2021-02-03 | 21:48:00 | Shed 7 East | Clark | • Toured up the Shed 6/7 ridge and conducted snow profile in the starting zone of Shed 7 East. • Surface snow conditions in this terrain feature consisted of ~16” of accumulated snowfall on the January 13th crust • Snow depths averaged ~75” or less at this location ~6300’ a.s.l • Objectives were to: o Observe snowpack instability in and around the Shed 7 area. o Assess snow surface conditions. o Conduct snow profile(s) in the upper starting zones of Shed 7 East. | • Overcast or broken skies for the entire field day. • Good visibility at all elevations. • Sporadic snowfall throughout the day with only trace accumulations. • Air temperatures were in the upper 20s (0F) at lower elevations and low 20s (0F) at upper elevations | • Minor cracking in upper ~6” of snowpack. No audible failures, and/or collapses observed. • ~4500’ and below...Breakable surface crust under 2-3” moist snow • ~4500 to 5800’…3-6” moist new snow on crust and moist facets/snow beneath crust to the ground. • ~5800 to 6300+…Approximately 10-18” of accumulated snow on the January 13th crust with a thin layer of facets found above crust. • Wind loading on easterly aspects observed at ridgeline elevation. • Snow profile conducted at ~6300’ on east aspect of Shed 7 East. (Profile & associated stability test results below). | No recent avalanche activity observed in the Shed 7 area • Recent debris did seem to be present in the “Larry” path located on the north face of “Devils Hump.” • Larry path debris appeared to have terminated approximately 2/3rds distance to the Canyon floor. |
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| 2021-01-28 | 21:57:00 | Grizzly Gulch to Shed 10 | Clark | • Toured in the central part of the Program Area today on both Snowslip and Running Rabbit Mountains up to 7600’ elevation. Descended the Shed 10 path. • Objectives were to observe the recent snowfall totals and any recent wind-loading, and to keep mapping the surface/near surface weak layers that have been forming over the past couple weeks. | • A partly sunny day until early afternoon when more clouds moved in. No precipitation during the tour. • Mostly calm or very light SW winds at all elevations. • Overnight low temperatures dropped to the teens to low-20s °F and daytime highs warmed to the mid-30s °F on the Canyon floor and the mid to high-20s °F at elevations above 6000’. | • Overnight snowfall totals ranged from 2-3”. The most recent wind-loading was mostly limited to elevations above 6500’ and most prominent on northerly aspects. • Triggered several tiny wind slabs (photo) on the lee side (north aspect) of a ridge above 7000’. These were failing on surface hoar and near surface facets and ranged from a 5-15” thick. • Also experienced multiple audible collapses on the lee side and on the crest of this same ridge along with several shooting cracks running as far as 25’. Again, failure was on surface hoar and near surface facets. • The Jan. 13th crust disappears just above 7000’. • The snowpack surface was moist in the afternoon on sunny aspects below 6000’ and there were plenty of small rollerballs from the overnight snow running on the crust on steep slopes. | • Observed a handful of very small (Destructive size 1) dry loose naturals in terrain outside the Program Area on northerly aspects. • Noted about 10 Destructive size 2 wet loose avalanches from the Jan 13th cycle initiating on steep slopes below 6500’. Debris from all of these terminated well above the rail. |
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| 2021-01-22 | 22:52:00 | Shed 7 W to Snowslip Weather Station | Clark | • Toured up the Shed 7 West path and onwards to the Snowslip weather station at 7000’. • Descended back down Shed 7 West. • Objectives were to fix the weather station, observe any recent wind-loading, and checkout the snow surface conditions. | • A brilliant sunny day with few clouds, calm to light westerly winds, and no precipitation. • Overnight low temperatures dropped to around 10 °F and daytime highs warmed to the mid-20s °F on the Canyon floor and the mid-teens °F at elevations above 6000’. | • On sheltered/forested and leeward (easterly aspects) slopes the crust was often breakable, sometimes even thin and friable and was starting to facet and breakdown. • The stoutest crust was on open slopes on windward (southerly-westerly) aspects where it was sometimes supportable on skis. • Also notable was a prominent layer of facets forming under the crust and also sometimes on top in locations where snow existed above the crust. • Also observed plenty of surface hoar development on all aspects (up to 4mm). In locations more exposed to the sun and wind the distribution was spotty. Sheltered and shaded aspects held more widespread/prevalent distribution. • No signs of instability observed on the tour. | • No recent avalanche activity observed. | |
| 2021-01-15 | 21:18:00 | Shed 7 W to Snowslip Weather Station | Clark | • Toured up the Shed 7 West path and onwards to the Snowslip weather station at 7000’. • Descended the same route. • Objectives were to look for recent avalanche activity, get a handle on the distribution and upper elevation of the Jan. 13th crust, and check on the weather station. | • Was expecting a nicer day but instead was treated to mostly obscured skies above 5000’ with rare breaks to let in a couple rays of sunshine. On-again/off-again flurries all day with a trace to 1” accumulation. • Calm or light W winds on the Canyon floor, but moderate to strong SW winds above 6000’. Minimal wind-loading, just the recent dust on top the crust. • Daytime high air temperatures warmed to about freezing on the Canyon Floor and up to the mid-20s °F at elevations above 6000’. | • The Jan. 13th crust was present all the way to our high point at 7000’ where it was still ½” to 1” thick. • But it was interesting how the crust varied across the terrain. It appeared that the winds on the 13th had affected the rainfall distribution. On sheltered/forested and leeward (easterly aspects) slopes the crust was often breakable, sometimes even thin and friable. The stoutest crust was on open slopes on windward (westerly) aspects where it was supportable on skis. • Also notable was a prominent layer of facets forming under the crust. Might be a layer of concern down the road. • Dug a hasty pit at 6600’ on an easterly aspect, HS=75”, ECTN15 about 12” down from surface on a layer of facets and what was likely the pre-storm surface. Looked hard for surface hoar but couldn’t find any. • No other signs of instability observed on the tour. | • Avalanche activity in this area from the Jan. 13th cycle was limited to a few D1 wet loose slides. |
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| 2021-01-05 | 23:00:00 | Shed 7 to Shed 5 | Clark | • Toured up the Shed 6/7 ridge to the Shed 7 weather station at 6100’ elevation. • Descended the Shed 5 area. • Objectives were to assess the recent wind-loading and snowpack stability with close attention to the Dec. 9th and 22nd crusts and check on the weather station. | • Mostly overcast skies with an occasional break for a ray or two of sunshine. No precipitation with light westerly winds. • Daytime high air temperatures warmed to about freezing on the Canyon Floor and up to the mid-20s/high teens °F at elevations above 6000’. | • Overnight snowfall totals above 6000’ elevation were about 3-4”. • Several generations of wind slabs above 5000’ from the consistent westerly winds over the past week. Some of these were reactive to ski cuts, while others were unreactive. • Shed 7 West cornice has grown considerably over the past week. • Breakable crust on the snowpack surface from the Canyon floor up to about 4800’. • Hasty pit dug at 5500’ on a SE aspect and a wind-loaded location. HS=43” with the Dec 22nd crust buried 20” down and the Dec 9th crust 30” down from the surface. No propagation and ECTN28 on the Dec 22nd crust. • One audile collapse in an area known as Test Slope 2 (5600’, SE aspect) after a few forceful ski stomps. Same location as the small avalanche mentioned above. | • No avalanche activity observed aside from a mini wind slab (D1) ski-triggered on a test slope on a SE aspect and 5600’ elevation (Test Slope 2 - photo). Debris terminated well above the rail. | |
| 2020-12-31 | 12:17:00 | Shed 11 to Path 1163 | Clark | • Toured up the Shed 10.7/11 ridge to the Shed 11 weather station at 6400’ elevation, then further up to 7200’ and the upper starting zone of Path 1163. • Descended the ascent route. • Objectives were to assess snowpack stability with close attention to the Dec. 9th and 22nd crusts, obtain a snow pit profile in Path 1163, and check on the weather station. | • Skies mostly obscured by fog above 6000’. • Light snow coming down as on-again/off-again showers with trace accumulations over the day at upper elevations. • Light westerly winds with moderate gusts above 5000’. • Daytime high air temperatures warmed to just above freezing on the Canyon Floor and up to the mid-20s/ high teens °F at elevations above 6000’. | • Overnight snowfall totals were about 2-3” on the Canyon floor and 3-4” above 6000’ elevation. • Recent wind-loading from light/moderate westerlies had formed some thin, fresh wind slabs on leeward aspects above 5000’. • On small test slopes above 5000’, was able to trigger some shooting cracks and small slabs on a thin layer of facets on top the Dec 22nd crust (photo). Also had one audible collapse at 6000’ and assume this also occurred on the Dec 22 crust/facet layers. • Re-visited the Shed 11 snowpit site at 6400’, HS=32”. Dec 9th crust buried 20” down and not propagating with ECT. ECTP3 x2 on the facets on top Dec 22nd crust, buried about 10” down. • Dec 22nd crust thins out and disappears around 6800’. • Snowpit profile in Path 1163 conducted at 7200’ on a southeasterly aspect and a rocky location with a shallower snowpack, HS=40”. No propagating failures with ECT (see pit profile for more details). | • No avalanche activity observed aside from some mini-slabs ski-triggered on test slopes. | |
| 2020-12-29 | 20:35:00 | Snowshed Mountain | Clark | • Toured up the NE ridge of Snowshed Mtn., across upper Tank and McDonald Ck. basins, and to the SE ridge and next to the glide avalanche that failed on the SE face above Sheep Creek sometime around Christmas. • Descended McDonald Ck. drainage. • Objectives were to take a closer look at the glide avalanche and to determine the upper elevation limit of the Dec 22nd crust and assess recent snowfall totals and recent wind-loading. | • Skies mostly obscured by fog, but occasional lifting allowed for some better visibility at times. • Very light snow coming down as on again/off again showers with trace accumulations over the day. • Light and variable winds at all elevations. • Daytime high air temperatures reached the mid-20s °F on the Canyon Floor but only the mid-teens or single digits °F at elevations above 6000’. | • There was about 5-15” of settled powder snow on top the Dec. 22nd crust depending on elevation. Around 6500’ this crust eventually disappeared. • Recent wind-loading was minimal with very little new wind slab development at all elevations we travelled through. • Snow profile conducted at 7100’ on an easterly aspect and about 30 m from the crown of the glide avalanche mentioned above. Dec 9th crust/facet combo was about 2’ below the surface. Propagation with hard force during an Extended Column Test (see pit profile) on a thin layer of facets resting atop the Dec. 9th crust. • No shooting cracks, audible collapses, or any other signs of instability during the ski tour. | • Snowshed avalanche failed sometime after Christmas morning, perhaps that night or next day. o Crown was located at about 7200’ elevation near the top of the path on a SE aspect, and was 1-4’ thick and about 500’ wide. o Debris terminus is uncertain, but saw what looked like debris at the bottom of the path near Sheep Creek (~3000’ vertical fall). o Classified as GS-N-R3-D3-G but it appeared that the glide failure may have also sympathetically triggered additional slab(s) that appeared to fail on some other buried persistent weak layer in the mid-pack. Suspect the Dec 9th crust/facet layer given our assessment of the crown and a snow pit profile dug near close by. • No other avalanche activity observed. |
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| 2020-12-23 | 22:48:00 | Burnout to Shed 7 West | Clark | • Toured up the ridge above Burnout and the Shed 4D/5 avalanche paths and then farther on into the upper starting zone of Shed 7 West to a highpoint at ~6600’. Then made road observations and checked manual weather stations on the Canyon floor. • Descended the Shed 5 Path. • Objectives were to look for any recent avalanche activity, determine the upper elevation limit of the Dec 22nd crust, assess the past 48-hour snowfall totals and recent wind-loading, and obtain a full snow pit profile in the Shed 7 area. | • Mostly overcast skies with occasional breaks that allowed for some brief sunshine. Clearing skies by late afternoon/sundown. • Very light snow coming down as on again/off again showers with trace accumulations over the day. • Light and variable winds at all elevations. • Daytime high air temperatures reached the mid-20s °F on the Canyon Floor and the mid-teens °F at elevations above 6000’. | • About 4-5” snow from yesterday on top of the Dec 22nd crust at the Canyon floor. The snowpack below the crust was moist at low-mid elevations. • Around 6500’ the Dec 22nd crust eventually disappeared and there was about 6-10” of new snow from yesterday and the snowpack became dry throughout. • Recent wind-loading was minimal with very little new wind slab development at all elevations we travelled through. • Snow profile conducted in the Shed 7 West Path at 6600’ on a southeast aspect. Dec 9th crust/facet combo was about 28” below the surface here. No propagation with an Extended Column Test (pit profile with more details in photo). • No shooting cracks, audible collapses, or any other signs of instability during the ski tour. | • No avalanche activity observed in the Program Area, but noticed an avalanche crown from Hwy 2 on the SE face of Snowshed Mountain above Sheep Creek (photo) in the Flathead Range. This appeared to be at least D2 in size and likely failed on a more deeply buried persistent week layer. Estimating that it ran sometime during the Dec 21-22 overnight warm-up. | |
| 2020-12-19 | 19:04:00 | Shed 11 | Clark | • Canyon road observations made first thing in the morning and then toured up the Shed 11/10.7 ridge to the Shed 11 weather station at 6400’ and then a bit further up the ridge to 6900’. • Descended the same route. • Objectives were to look for any recent avalanche activity, assess the extent of recent wind-loading, assess the general snowpack structure, and check on the weather station. | • Overcast skies with occasional breaks that allowed for some brief sunshine. • Light snow/graupel coming down as on again/off again showers with 1-2” accumulation over the day. • Daytime air temperatures were in the mid-30s °F on the Canyon Floor and the mid-20s °F at elevations above 6000’. | • Below 5000’ elevation the snowpack consists of 4-6” of a snow/graupel mix resting on top of a crust, or just directly on the ground where all the Nov/Oct snow had melted off. • Above 5000’ found a poor snowpack structure with a 6-15” thick slab from this week’s new snow resting atop a thin layer of weak faceted snow just above the Dec 9th crust. Found this structure in multiple hand pits and noted some snappy easy hand shears. • Snow profile conducted just below the Shed 11 weather station at 6400’ on a south aspect. Same poor structure as noted above and ECTP 23 and 18 about 10” down from the surface on the facet/Dec 9th crust combo (pit profile with more details in photo). • Dug another hasty pit at 6900’ also on a south aspect. Snow depth=50” with the facet/crust combo buried about 14” down from the surface. ECTNs and CTH 23 SC on that layer in this location. • Moderate westerly winds with occasional strong gusts were actively loading easterly aspects all day. • Observed some shooting cracks, 2-10’ long in the freshest wind slabs (2-6” thick) in a few locations above 5000’. • One small audible collapse on the ridge below the weather station around 6200’. Suspect the facet/crust layers noted above. | • No avalanche activity observed. | |
| 2020-12-02 | 17:23:00 | Shed 7 area | Steiner | • Toured up the Shed 6/7 ridge and conducted snow profiles in the starting zones of Shed 7 East and West. • Snow conditions overall in this terrain feature consisted of facets and crusts. • Snow depths averaged around 30” or less at starting zone elevations ~6300’. • Canyon floor snow depths averaged 12” comprised of a stout melt freeze crust as a base layer. Objectives were to: • Observe recent avalanche activity in and around the Shed 7 area. • Assess snow surface conditions and collect some other baseline snowpack data. • Conduct snow profile(s) in the upper starting zones of Shed 7 East and West. | • Clear for the entire field day. • Excellent visibility at all elevations. • No precipitation throughout the day with calm conditions at all elevations. • Inverted atmospheric conditions… • Air temperatures were in the teens at lower elevations during the morning hours and mid- 30s (0F) at upper elevations during the afternoon hours. • Air temperatures remained below freezing during the entire day at lower elevations (Below ~5000’). | No shooting cracks, audible failures, and/or collapses observed. • ~4500’ and below: Small surface hoar and up to 2” of near surface facets on supportable crust • ~4500’ to 5800’: 2mm surface hoar on shaded aspects/ terrain features with ~2” of near- surface facets. • ~5800’ to 6300’+: 2-4mm surface hoar on snowpack surface without direct solar exposure. Surface hoar was present on non-shaded aspects but without intense solar exposure (~SE aspects). Also, on shaded and non-direct solar aspects, up to 3” of near-surface facets on established crust. • No windloading throughout the day. • Snow profiles conducted at ~6300’ on southeast aspects and at starting zone elevations in both Shed 7 East and West. Snowpit profile details & associated stability test results, see photos. | • No slab avalanche activity observed. • Dated cornice fall observed on NE exposure in on the Shed 7 West ridgeline. |
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| 2020-04-09 | 16:19:00 | Grizzly Gulch to Shed 11 | Clark | • Ascended the basin between Running Rabbit and Snowslip Mountains then up and over the south summit of Running Rabbit, and down to the Shed 11 weather station. • Continued down the Shed 10.7/11 ridge to the rail. • Objectives were to observe the recent avalanche activity, continue to assess the snowpack structure with particular attention to the late March persistent weak layer, and perform a welfare check on the Shed 11 weather station. | • Mostly clear skies with calm or light westerly winds and no precipitation. • Overnight lows in the mid to high-20s on the Canyon floor and hovered around freezing above 6000 feet. Daytime highs neared 60 °F on the Canyon floor and the low-40s to near 50 °F above 6000 feet. | • Supportable melt-freeze crust this morning up to about 6500 feet on east aspects and all the way to 7400 feet on south aspects. • Easterly aspects were beginning to soften by 0930 and started producing rollerballs around rock bands by about noon. • Dug down to the late-March crust/facet layer at elevations above 6500 feet and found it was still reactive in stability tests in some locations. An Extended Column Test (ECT) at 7200 feet on an easterly aspect yielded ECTP22 on this layer which was about 2 feet down from the surface. The snowpack was dry in this location. • In another pit at 7200 feet on a south aspect the late-March crust/facet layer was buried about a foot down from the surface and yielded ECTN15. Snowpack was moist on this slope. • The late-March crust was about a foot down at the Shed 11 weather station and the snowpack was wet down to the crust. Could not really find any facets around the crust in a hand pit but did experience one audible collapse on the Shed 10.7/11 ridge (6400 feet, south aspect) as I was heading down. | • Widespread natural wet loose avalanche activity over the past 2 days with dozens of avalanches at the upper elevations (mostly above 5500 feet) on E-S-W aspects. Most were small in size (Destructive size 1 to 1.5 of 5), but a few grew big enough to reach Destructive size 2 of 5 (could bury or injure a person) in paths such as Shed 11, 1163, and Shed 10. • One very small slab (D1) observed in Grizzly Gulch (east aspect, ~6400 feet). • All debris in paths threatening the rail terminated well above the grade. • Just outside the Program Area on the east face of Snowslip Mtn., and above Shields Creek, a larger (Destructive size 2) slab avalanche ran sometime in the last 2 days. Observed from the highway but it appears to have run on the late-March crust/facet layer and may have been triggered by a cornice fall/smaller slab avalanche from above (see photo below). |
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| 2020-04-06 | 17:48:00 | Burnout to Shed 7 West | Clark | • Ascended the SE ridge of Snowslip Mtn. above the upper reaches of the Burnout, Shed 4D, Shed 5, and Shed 7 avalanche paths to a high point in Shed 7 West at 6600 feet. • Descended the same route. • Objectives were to look for any recent avalanche activity, observe snowfall totals since the March 24th high pressure period, and further investigate the snowpack structure and a possible persistent slab problem that has been reported in the nearby Flathead Range. | • Broken skies with occasional very light snowfall interspersed with dry and sunny periods. • Winds were mostly calm below 6000 feet and light with moderate gusts usually from the SW above there. • Overnight lows hovered around freezing on the Canyon floor and ranged in the mid to high-20s °F above 6000 feet. Daytimes highs climbed into the mid-40s °F on the Canyon floor and near freezing above 6000 feet. | • This morning’s rain line extended up to about 4000 feet with a rain/snow mix up to about 5000 feet, with all snow above that elevation. • The March 29th rain line extended up to about 5300 feet as evidenced by a very stout, supportable, and slippery crust up to this elevation. There was about 8-15 inches of new snow on top of this crust and no weak faceted snow was observed at the crust/new snow interface. The snow beneath the 3/29th crust was wet and isothermic. • Above 5300 feet the 3/29 rain crust thins out and a poor snowpack structure associated with the 3/24 facet/crust layer was widespread and present in several hand pits and two additional snow pits with stability tests (photo below). • However, in terrain above 5300 feet, we did not observe any direct signs of instability such as collapses, shooting cracks, or slab releases on small test slopes. • Depths down to the 3/24 interface above 5300 feet ranged from 20-30 inches and this snow was right side up in hardness with Fist-hard on top, firming up to 4F-hard going down the column. A thin sun crust from Saturday the 4th was also present about 4-6 inches down from the surface. • Dug a snowpit and conducted a full profile for the upper half of the snowpack in Shed 4D at 5770 feet on an easterly aspect (pit profile below). The first Extended Column Test (ECT) yielded an unstable result on the 3/24 crust/facet layer, ECTP22. But the second ECT did not produce propagating results and a Propagation Saw Test also did not yield unstable results. • Dug a second snow pit in Shed 7 West at 6600 feet on an east aspect. Non-propagating results on the 3/24 crust/facet layer along with two different compression tests (CT) yielding CT25 BRK and CT24 RP on the same layer. The slab on top of the 3/24 interface was about 20 inches thick. | • 2 very small (D1) skier-triggered wet loose sluffs on low elevation slopes near Burnout (~4700 feet, east aspect) with debris running 50 feet. Debris terminated well above the rail. • Widespread natural wet loose avalanche activity this afternoon present in several paths above the rail including: Burnout, Shed 5, Shed 10, Path 1163, and Shed 12. All debris was small in size (D1-1.5) and terminated well above the rail grade with the exception of Shed 12 where it just reached the top of the Shed. • No slab avalanche activity observed. |
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| 2020-04-03 | 23:05:00 | Path 1183 | Clark | • Ascended the ridge to the north of and above Cascadilla Creek to gain access to the upper starting zone (around 5900 feet) of the 1183 avalanche path. • Descended the ridge located on skier’s left of Path 1183 and to the east of Wahoo Creek. • Objectives were to look for any recent avalanche activity, observe recent snowfall totals, and further investigate the snowpack structure and persistent slab problem that has been reported in the Flathead Range. | • Overcast or obscured skies with snowfall ranging from S-1 to almost S5 for short, 10-15 minute intervals. • Winds were calm or light and coming from variable directions, sometimes west/southwest, and at other times from the east. | • Sunday’s (3/29) rain line extended up to about 5300 feet as evidenced by a very stout, supportable, and slippery crust up to this elevation. Skinning was challenging at times. New snow depths on top of this crust ranged from 5-10 inches. No buried facets observed on top of the 3/29 crust and no real signs of instability save for the loose snow sluffing mentioned above. • Above 5300 feet the recent snow depths increased quickly. Depths down to the 3/24 interface ranged from 20-30 inches and was right side up in hardness with Fist-hard on top, firming up to 4F-hard going down the column. • Many hand pits revealed a poor snowpack structure in most locations above 5300 feet with facets on crust layers and/or facet layers sandwiched between crusts associated with the 3/24 interface. • However, in the terrain we travelled through we did not observe any direct signs of instability such as collapses, shooting cracks, or slab releases on small test slopes. • Also no propagating results observed in two different Extended Column Tests. The first at 5700 feet on a north aspect and the second at about the same elevation on an east aspect. We did get some ECTNs within the different storm layers from the last week. | • 3-5 very small (D1) skier triggered loose snow sluffs in the lower runout zone of Path 1183 (~4000 feet, north aspect) with debris running 50-100 feet. • No slab avalanche activity observed. |
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| 2020-03-31 | 17:13:00 | Shed 10 | Clark | • Ascended the southeast ridge of Running Rabbit Mtn. along the eastern edge of the Second Slide avalanche path and upwards into the uppermost starting zone of the Shed 10 avalanche path. • Descended the Shed 10 path. • Objectives were to observe the overnight snowfall totals and the extent of the associated wind-loading at upper elevations. | • Morning hours were pleasant with scattered snow showers (S-1) alternating with partly sunny skies, calm or light westerly winds, and temperatures around freezing at the Canyon floor and in the mid-20s at upper elevations. • Around 1300 winds clocked around to the E-NE and increased in speed as colder air spilled over the Continental Divide. Cloud cover increased as well and temperatures quickly dropped about 10 degrees into the mid-20s °F on the Canyon floor. | • Overnight snow totals ranged from 1 inch on the Canyon floor to about 6-8 inches above 6000 feet. • New wind slabs were found on easterly aspects above 6000 feet and were up to 10 inches thick. • Save for the one little slab mentioned above, other test slopes were unreactive to ski cuts with no cracking, collapsing, or audible failures observed. • The most recent melt-freeze crust under last night’s snow was breakable up to about 5500 feet then mostly supportable at elevations above. • The snowpack on south-facing slopes below 5500 feet has melted a lot with many slopes melted out completely, or at least having large patches of bare ground. East-facing slopes at low elevations are holding onto more snow, and some locations along the rail at the east end of the Program Area still have 2-3 feet of snow. • Snow depths increase quickly above 5500 feet and depths ranging between 6, 8, and even 10+ feet are common above 6000 feet. | • One very small (destructive size 1 of 5) wind slab intentionally triggered on a small test slope around 6500 feet on the crest of the SE ridge (photo below). SS-ASc-R1-D1-I, slab was about 15 feet wide and 3-8 inches thick. • Some small (D1) older wet loose avalanche debris was observed in Path 1163, thinking this ran over the weekend when the weather was warmer and there was some rainfall. • Some rollerball activity within the new snow below 6500 feet on steep, sun-exposed slopes that initiated around rock band. Most activity occurred in the morning before a cold front arrived in early afternoon. |
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| 2020-03-26 | 20:55:00 | Shed 11 | Clark | • Ascended the south face of Running Rabbit Mtn. along the ridge separating the Shed 11 and Shed 10.7 avalanche paths to a high point at the Shed 11 weather station at 6400 feet. • Descended the Shed 11 path. • Objectives were to work on the Shed 11 weather station and observe the extent of any recent wind-loading. | • Mostly cloudy skies with a couple brief S-1 flurries. • A breezy day with light to moderate W-SW winds at all elevations. Wind-loading was minimal in our location but we could see that it was heavier above 7000 feet on peaks nearby such as Furlong and the Devils Hump • Afternoon highs reached the mid-30s °F on the Canyon floor and the mid-20s °F above 6000 feet. | • Travelled on a stout and supportable melt-freeze crust from the Hwy all the way to 6400 feet. In some wind-sheltered locations there was a trace to 2 inches of new soft snow on top of the crust. • No wind-slabs encountered and the light to moderate SW winds during the day were transporting only minimal amounts of snow above 6000 feet and none below that elevation. • No cracking, collapsing, or audible failures observed. • The snow surface was still a solid crust when we left the weather station at 1500 and remained firm till about 5000 feet where it finally softened a bit to make some turns in the corn while dodging patches of bare ground. | • No avalanche activity observed | |
| 2020-03-17 | 22:53:00 | Path 1183 | Steiner | • Toured up the Wahoo drainage and worked our way up and to the east to crest the ridge at ~5800’. • This ascent put us on the ridge that separates Wahoo drainage and the next drainage to the east. • This drainage to the east is unnamed but we refer to it as “Path 1183.” The reason for the Path 1183 reference is that it geographically correlates with Mile Post 1183 on the BNSF rail grade, is avalanche prone, and has historically conveyed large magnitude avalanche debris on the rail grade. Objectives were to: o Observe recent avalanche activity in and near Path 1183 o Assess snow surface conditions in Path 1183 o Conduct a full profile in the upper starting zone of Path 1183. o Descend Path 1183 back to the rail grade and US Highway 2 | • Clear to partly cloudy skies for the entire field day with excellent visibility at all elevations. • No precipitation throughout the day with calm to light winds at all elevations. • Air temperatures were in the teens at lower elevations during the morning hours and 20s °F at upper elevations. • Mid-day air temperatures had risen to above freezing on all aspects at lower elevations (Below ~4000’) and on solar aspects at elevations up to ~5600’ | • ~4500’ and below...~2 inches (5 cm) of near surface facets on supportable crust. • ~4500 to 5800’… Shaded: 2 mm surface hoar on top of 4-5 inches (10-12 cm) new snow. Solar: ~1 inch (3 cm) breakable crust with near-surface-facets (NSF) beneath. • No windloading throughout the day. • No collapsing or audible failures observed. • Full profile conducted at 5500’ in Path 1183 on a 38-degree slope with a northeasterly aspect (see profile below). ECTX during an Extended Column Test. | • Very small windslab and loose snow avalanche activity was observed in the Wahoo drainage on ascent. This activity was observed on an easterly (solar) aspect at approximately 5600’ elevation. It appeared this very small slab was triggered by a point release from above. • We also observed evidence of small to moderate slab avalanche activity on a northerly aspect at approximately 6000’ elevation. Residual crown of this avalanche did not appear to be recent. Geographically, it appeared to be on steeper terrain just above the Wahoo bench where the small pond exists. |
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| 2020-03-11 | 22:10:00 | Burnout to Shed 7 West | Clark | • Toured up the SE ridge of Snowslip Mountain above the Burnout and Sheds 4D, 5, and 7 paths to the Shed 7 weather station. Then continued up to about 6700 feet in the Shed 7 West path. • Descended the Shed 5 path. • Objectives were to observe the past 24-hour snowfall totals and the extent of recent wind-loading, and look for any new avalanche activity. | • Mostly cloudy skies with steady snow and graupel showers interrupted by brief periods of broken skies and no precipitation. Snowfall was heavy at times, up to S5 intensity for short periods (photo). • Moderate SW winds with strong gusts above 5500 feet. Winds on the Canyon floor were light from the west or calm. • Air temperatures on the Canyon floor hovered just above freezing this afternoon and were in the mid-20s °F above 6000 feet. | • New snowfall overnight and today ranged from 4-10 inches on the Canyon floor with greater amounts at the east end of the Program Area. Above 6000 feet there was about a foot of new snow. This was accumulating on a stout melt-freeze crust that appeared to exist everywhere where I travelled except for shady aspects above 6000 feet • Snow surface was moist below about 5500 feet and a lot of the new snow consisted of graupel. • Moderate to strong SW winds were actively loading leeward slopes and forming fresh wind slabs for much of the day above 5500 feet. • Ski cut many steep test slopes resulting in very few signs of instability. New wind slabs were either unreactive or only produced minor cracking (2-3 feet long). • Ski cuts also had limited effect at initiating loose snow sluffs despite all the fresh snow deposited on a melt-freeze crust. • Dug a snow pit in the Shed 7 West path at 6600 feet on an east aspect. Total snow depth was 75 inches with about a foot of new snow on top of the most recent melt-freeze crust. Extended Column Test yielded ECTN10 about 12 inches down on the new snow interface. No additional fractures observed. | • One wet loose sluff, Destructive Size 1 of 5 ran today in a small path on the rail called Umbrella Fence, located between Sheds 7 and 6. Associated debris made a small pile next to Main 1 about 1-4 feet deep and 15 feet wide. • A couple small D1 loose dry sluffs intentionally triggered with ski cuts in the Shed 5 path around 5500 feet (photo). • No slab avalanches observed. |
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| 2020-02-28 | 23:45:00 | Sheds 7, 8, 9 | Clark | • Toured up the Shed 7/8 ridge to the upper starting zone of the Shed 8 path, then continued up the ridge to the Snowslip weather station. • Descended the Shed 7 West path. • Objectives were to look for any recent avalanche activity due to the recent warming, check on the Snowslip weather station, and put a full profile in the Shed 8 Path. | • Mostly sunny skies with no precipitation and moderate westerly winds above 5500 feet and light westerlies on the Canyon floor. • Air temperatures on the Canyon floor reached the low-50s °F this afternoon and the low-40s to mid-30s °F above 6000 feet. | • Snow surface was moist on all aspects below 5000 with rollerballs running by 1030. • The Shed 7 West cornice is getting large, 6-10+ feet tall in places. • A variety of snow surfaces encountered today: moist snow on sunny aspects up to 7000 feet with a mix of wind slabs (supportable at times), wind board/crust (breakable), and stiff powder on shady aspects. • Dug a snow pit and conducted a full-depth profile in the Shed 8 path at 6200 feet on a SE aspect, 34° slope. Total snow depth=63 inches with propagating results with an Extended Column test on a layer of facets about 16 inches down from the surface (pit profile below). | • Multiple wet loose avalanches, D1 to D1.5 in size, observed in paths 1163, Infinity, Shed 8, and Burnout. Associated debris terminated above the rail grade. • Widespread rollerball activity on sunny aspects at all elevations. • No slab avalanche activity or cornice falls observed. |
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| 2020-02-26 | 23:25:00 | Shed 7 | Clark | • Toured up the Shed 6/7 ridge to Shed 7 weather station, then continued to the upper starting zone of Shed 7 West. • Descended the Shed 7 West path. • Objectives were to observe the extent of recent wind-loading, look for any recent avalanche activity, and hunt for buried surface hoar. | • Mostly cloudy skies with steady moderate westerly winds above 5500 feet. • Occasional S-1 to S2 snow flurries. No new accumulation on the Canyon floor with ~1-2 inches new snow above 6000 feet during the day. • Air temperatures on the Canyon floor reached the mid-30s °F this afternoon and the low to mid-20s °F above 6000 feet. | • Moderate westerly winds were forming new wind slabs on easterly aspects above 5000 feet. We found new drifts up to 10-15 inches thick at most, but in other locations only 2-5 inches thick. These were mostly unreactive to ski cuts or only produced some minor cracking on steep test slopes. • The Shed 7 West cornice is getting large, 6-10+ feet tall in places. • Looked for buried surface hoar in several hand pits at all elevations and on the aspects we travelled through: N-E-S and didn’t find any. • Dug a test pit at 6600 feet on a NE aspect down 47 inches to the 2/1 crust. No surface hoar found. Total snow depth=118 inches. Extended Column Test yielded ECTX. • Dug a 2nd test pit at 6650 feet on an ESE aspect in the Shed 7 West path down 53 inches to the 2/1 crust. Found a thin (~1/4 inch) sun crust formed during last week’s sunny weather 14 inches down, ECTN19 on this layer. Total snow depth=93 inches. | • No new avalanche activity observed since yesterday’s small D1 loose snow avalanches. • Debris from last week’s cornice fall in Shed 7 West ran about 1000 vertical feet down path, terminating well above the rail grade. |
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| 2020-02-25 | 19:02:00 | Burnout to Shed 5 & Road Obs | Clark | • Afternoon tour up the SE ridge of Snowslip Mtn. and above the Burnout, Shed 4D, and Shed 5 paths to the Shed 7 weather station at 6400 feet. • Descended Shed 5 path. • Objectives were to observe new snowfall totals, determine the extent of today’s wind-loading, and look for any recent avalanche activity. | • Mostly cloudy skies with brief breaks of sunshine. Very occasional S-1 snowfall in the morning but mostly dry in the afternoon • Calm or light southwest winds at all elevations. • Air temperatures on the Canyon floor reached the mid-30s °F this afternoon and the low to mid-20s °F above 6000 feet. | • 7-9 inches of new, low-density snow fell overnight on the Canyon floor and 10-12 inches accumulated above 6000 feet. • Only minor amounts of wind-loading beginning around mid-day and mostly limited to elevations above 5500 feet. New wind slabs were only 1-4 inches thick and produced only minor cracking with ski cuts. • Moist snow surface up to about 5500 feet. • Dug a test pit about 3 feet deep on an easterly aspect at 5800 feet. Total snow depth=69 inches. Overnight snowfall here was 12 inches deep. No propagating fractures with an Extended Column Test, but ECTN23 16 inches down from the surface on a layer of near-surface facets formed during last week’s dry weather. The 2/1 crust was buried 37 inches down. | • Several D1 loose snow avalanches observed, mostly below 6000 feet and limited to steep, sun-exposed slopes. • No slab avalanches or any new cornice falls observed. |
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| 2020-02-19 | 17:02:00 | SW Ridge Running Rabbit-Shed 11, Path 1163 | Clark | • Toured up the SW ridge of Running Rabbit Mtn. to the weather station at 6400 feet and then continued up to the south summit and the upper starting zone of Path 1163 at 7200 feet. • Descended Shed 11 path. Objectives were to: • Fix the wind sensor on the weather station. • Observe changes to the snow surface as our weather transitions to clear cold nights coupled with sunny days and warming temperatures. • Look for any recent avalanche activity. | • Mostly clear skies with no precipitation and excellent visibility at all elevations. • Calm or light west winds at all elevations. • Air temperatures were cold and inverted in the morning with sub-zero °F values on the Canyon floor and ranging from 5-10 °F above 6000 feet. • Afternoon highs reached the high-20s to low-30s °F on the Canyon floor and into the mid-teens to low-20s °F above 6000 feet. But all that sunshine made it feel much warmer. | • No wind-loading occurring throughout the day. • We now have a new crop of surface hoar. It was most pronounced starting at about 5000 feet and extended up to my high point at 7200 feet (photo). Crystals were wilting and melting on sunny aspects but staying preserved in the shade. • Moist snow surface on sunny aspects at all elevations. Shady aspects kept cold and dry snow. • Old wind slabs were unreactive to ski cuts/stomps, but was able to initiate some D1 wet loose on steep, sunbaked slopes with ski cuts in the afternoon. | • A few rollerballs and some limited wet loose avalanche activity began around late-morning on sunny aspects. A handful of D1 wet loose observed, mostly below 6000 feet and limited to steep slopes with exposed rock. • A very thin sun crust on the snow surface that formed yesterday/night before seems to have inhibited loose snow avalanche activity today. • No slab avalanches or any new cornice falls observed. |
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| 2020-02-17 | 23:31:00 | Burnout, Shed 4D, Shed 5 | Clark | • Toured up the SE ridge of Snowslip Mtn and above the Burnout, Shed 4D, and Shed 5 avalanche paths to our high point at 6400 feet at the Shed 7 weather station. • Descended the Shed 5 path. Objectives were to: • Perform welfare checks on the Shed 4 and Shed 7 weather stations. • Observe new snowfall totals and wind-loading from the past few days and look for any recent avalanche activity. • Conduct a full snowpit profile in the Shed 5 avalanche path. | • Intense, but very brief snow showers at times (S2-S5) alternating with longer periods of broken skies and sunshine. Only a trace to 1 inch of new snowfall over the day. • Calm or sometimes light SW winds at all elevations. • Air temperatures in the mid to high-20s (0F) throughout the day. | • No wind-loading occurring throughout the day but evidence of older wind slabs near ridgelines. Only some minor cracking in these with ski cuts. • 3-5 inches of new snow over the past 24 hours. • The 2/1 crust is now buried about 12 inches deep on the Canyon floor, about 20 inches deep at 5000 feet, and 2-4 feet deep above 6000 feet. • No collapsing or audible failures observed. • Full profile conducted in the upper starting zone of Shed 5, 5800 feet, E aspect, 37° slope. Total snowpack depth at profile location was 79” (pit profile below). • Stability tests were limited to one Extended Column Test. Non-propagating results in the upper 20 inches. No fractures on the 2/1 crust and buried 30 inches down at the pit location. | • A handful of very small (D1) loose dry sluffs on steep sun-exposed slopes. • Small cornice fall in the Shed 7 West path. • No slab avalanche activity observed. |
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| 2020-02-12 | 22:15:00 | Shed 10.7 & 1163 | Steiner | • Toured up the Shed 10.7/ 11 ridge to the Shed 11 weather station at approximately 6300’. • Then continued to the starting zone elevation of Path 1163 at approximately 7200’. • Descended Shed 10.7 path. Objectives were to: • Perform a welfare check on the Shed 11 Weather Station and attempt to get wind sensor working again. • Continue to upper starting zone elevation of Path 1163, check on conditions and look for any recent avalanche activity. • Also conduct a full profile adjacent to Path 1163 on a slope with similar aspect, elevation, and slope angle as the avalanche path starting zone. | • Cloudy to partly cloudy skies for the entire field day with excellent visibility at all elevations. • Minimal precipitation throughout the day with calm to light wind conditions at all elevations. • Air temperatures were in the teens and twenties (0F) at all elevations throughout the day. | • No wind-loading occurring throughout the day. • Eight inches (8”) and up to two feet (24”) of accumulated snowfall now resting on 2/1/2020 crust. • The 2/1 crust extended up to our high point at 7200 feet where it had thinned to less than 1 inch (2 cm) thick. • Wind slabs from yesterday and earlier up to 1F- hardness established in wind affected areas… mostly observed on easterly through southerly aspects. Minimal cracking with ski cuts on these slabs. • No collapsing or audible failures observed. • Full profile conducted on ridge just west of Path 1163 (pit profile below) • Profile location was on a southeast aspect, 7100 feet elevation, 38-degree slope. • Total snowpack depth at profile location was 72” (180 cm). • Stability tests were limited to one (1) Extended Column Test. Non-propagating results in the upper 20 inches within the standard 30 taps. But propagation (ECTP35 @25 cm) with extra hard force on a layer of facets above a crust near the bottom of the snowpack. After propagation the column slid into the pit. | • No recent avalanche activity was observed. | |
| 2020-02-04 | 22:00:00 | Shed 7 and Shed 9 | Steiner | • Toured up the Shed 7 West avalanche path into the upper starting zone and then continued gaining elevation to the ridge that separates Shed 7 West and the Shed 9 starting zone. Traversed upper reaches of the Shed 9 basin to a south facing aspect where we conducted a full profile. • Objectives were to: o Observe surface snowpack condition at all elevations, o Observe Shed 7 West cornice formation and loading distribution. o Observe Shed 9 loading distribution and cornice formation, o Examine snowpack structure in the upper starting zone elevations of Shed 9. | • Clear to partly cloudy skies for the morning hours into the early afternoon accompanied by excellent visibility at all elevations with no precipitation. • By approximately 1400, overcast skies along with very light snow (S-1) began. • Westerly winds observed throughout the day with wind strength increasing as the day progressed. • Wind strength throughout our tour was substantial enough to be transporting wind onto leeward aspects (easterly and northeasterly) at elevations above 5200’ elevation. | • Active windloading occurring throughout the day on northeasterly and easterly aspects. • ~Four inch (~4”) to ~six inch (~6”) very soft windslab beginning to form on leeward slopes above 5200 feet elevation. • No collapsing or audible failures observed. • Full profile conducted on a 37-degree slope in the starting zone of Shed 9 (pit profile below). • Profile location was on a south aspect at 6700’ elevation. • Total snowpack depth at profile location was 56” (140 cm). • Stability tests were limited to one (1) Extended Column Test with no propagating results. • Please refer to Shed 9 profile JPEG for additional data. | • No recent avalanche activity was observed. | |
| 2020-01-27 | 21:44:00 | Shed 7 | Clark | • Toured up the Shed 6/7 ridge on the south face of Snowslip Mtn. to the Shed 7 weather station then continued up the ridge above Shed 7 West to the Snowslip weather station. Descended the Shed 7 West path. • Objectives were to look for any recent avalanche activity, observe new snow depths and wind-loading at upper elevations since Jan. 24th, continue to monitor the snowpack structure and stability in this area, and check on the above-mentioned weather stations. | • Light to moderate SW winds with scattered snow showers, heavy at times (S5) interspersed with broken skies and no precipitation. • Air temperatures were near freezing on the Canyon floor and in the low to mid-20s °F above 6000 feet. | • No signs of instability (no cracking, collapsing, or recent avalanches). • Light to moderate wind transport with isolated and unreactive pockets of wind drifted snow on small test slopes. • Roughly 2 to 4 inches of new snow sitting on top of the latest melt-freeze crust. Minor sluffing at low and mid-elevations where the crust was more developed. • Dug 1st snowpit on a northerly aspect at 6600 feet. Snow depth=96 inches, Extended Column Test yielded ECTN22 down 12 inches on the Martin Luther King (MLK) crust. Holiday facet layer was about 45 inches down and unreactive. • Dug a second snowpit on a southeasterly aspect at 6600 feet. Snow depth=73 inches, ECTN22 down 10 inches on the MLK crust. Holiday facet layer was about 36 inches down and unreactive. • The most recent melt-freeze crust reached to ~ 6500 feet. 2 to 3 in. thick at low and mid-elevations and then quickly dissipated above 6500 feet. Crust was supportable on skis down to 3500 feet. • At 6500 feet, MLK and Holiday crusts were decomposing and difficult to locate. Both had small grained facets above and below. | • No recent avalanche activity observed. • Found the terminus of the debris from the avalanche that ran in Shed 7 West sometime around January 7th. This was located about 800 vertical feet above the rail grade at 5200 feet elevation and had piled up in the creek bed to about 10 feet deep at the maximum. |
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| 2020-01-24 | 17:38:00 | Shed 10.7 & Path 1163 | Clark | • Toured up the Shed 10.7 ridge on the south face of Running Rabbit Mtn. After checking on the Shed 11 weather station, continued up the SW ridge of Running Rabbit to 7200 feet and checked on the uppermost starting zone of Path 1163. Descended the same route. • Objectives were to observe recent avalanche activity and new snow depths and wind-loading above the rain/snow line. Also wanted to seek out some steep, rocky, high elevation terrain with shallow snowpack depths and assess the snowpack structure/stability at a location representative of a possible deep persistent slab trigger point. | • Very light rain with temperatures in the mid-30s to 40 °F from the Canyon floor up to 5500 feet with calm to light SW winds. • Very light rain/snow mix from 5500 to about 6500 feet with light SW winds. • Occasional very light (S-1) snowfall with temperatures just below freezing and light SW winds from 6500-7200 feet. • Skies were mostly cloudy with occasional breaks revealing some blue sky. | • No collapsing or audible failures during the tour. • Ski cuts on small test slopes did not produce any cracking or slab releases. But below 6000 feet they set off plenty of nice sized rollerballs but without any wet loose avalanches. • No wind-loading due to a fully wet snowpack surface up to about 6500 feet. Above this elevation a slightly moist snowpack surface up to 7000 feet combined with an actively forming rime crust acted to limit blowing and drifting snow. • The recent (MLK) rain crust was only about ¼ thick and present from the Canyon floor up to 6500 feet where it thinned and disappeared. There was 4-5 inches of snow on top of the crust around 6000 feet. • Dug a snowpit and conducted a full profile on the ridge immediately west of the upper starting zone of Path 1163, 7200 feet, easterly aspect, 28° slope (pit profile below). • Snow depth here was only about 40 inches and the November crust/facet layer was present at the base about 30 inches down. • The holiday crust was not present at this location which is consistent from earlier observations. • The first Extended Column test yielded ECTP16 on the basal facets and the column quickly slid into the pit. The second ECT yielded ECTP16 on the same layer. | • Rollerballs were widespread on slopes steeper than 30° and below 6000 feet, but only a few progressed to wet loose avalanches. The few wet loose avalanches observed were small D1-D1.5. • No slab avalanche activity observed. |
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| 2020-01-21 | 21:00:00 | Rescue/Wahoo/Path 1183 | Steiner | • Toured up from the Rescue Creek trailhead, accessed the Rescue Creek basin and then ascended the looker’s left most avalanche path to the benched terrain between Rescue Creek and Wahoo Creek. Traversed on this bench on a diagonal to the ridge that separates the Wahoo drainage from the Cascadilla drainage. Followed this ridge to the northeast until it terminated in the Path 1183 starting zone terrain. • Objectives were to observe recent avalanche activity, evaluate snowpack structure, and observe snow depth at the starting zone elevation of Path 1183. | • A rather benign day with air temperatures around freezing, light variable direction winds, and scattered snow showers. • No active windloading observed. • Terrain above ~6500’ elevation was obscured due to low clouds. | • No collapsing or audible failures observed. • Profile conducted on a 35-degree slope in the starting zone of Path 1183. • Elevation at our profile location was approximately 5800’ and exposure was northeast. • Due to time constraints, we did not dig to the ground. • Total snowpack depth at profile location was 102” (260 cm). • Profile depth from the snowpack surface was 72” (184cm). • Stability tests were limited to Extended Column Test and Compression Test. • No propagation in the ECT but ECTN results were recorded at: o 8” (20cm), 14” (35cm), and 64” (70cm) from the snowpack surface. • Compression Test results were on the same identified layers as the ECT with resistive planer results. • Skied down a westerly aspect in the afternoon into the Wahoo drainage and found extensive rollerballs from the day before but no loose snow avalanches observed. | • We observed the very impressive vegetation damage and debris in the Rescue Creek drainage as well as in the mid-upper elevations of the Wahoo drainage from the large avalanches on Nyack Mountain that were reported and well documented by the Flathead Avalanche Center last week. • Also observed debris from what appeared to be a more recent avalanche in the upper reaches of the Cascadilla basin. Debris terminated in the upper elevations of the basin (~6400’) and remained confined to non-vegetated terrain. • No other recent avalanche activity was observed. |
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| 2020-01-14 | 21:00:00 | SW Ridge Running Rabbit/Shed 11 | Steiner | • Toured up the southwest ridge of Running Rabbit Mountain to the Shed 11 weather station at 6300 feet (‘) and descended same route. • Objectives were to observe recent avalanche activity, wind and storm slab formation at all elevations, and do a welfare check on the Shed 11 weather station. | • Below ~5600, moderate easterly winds, light to moderate snowfall, wind-transported snow, and air temperatures below zero (F0). • Above ~5600’ light westerly winds, light snowfall, and air temperatures in the single to double digits (10-120F) • To re-iterate, active wind loading and cross loading was occurring on westerly aspects below ~5600’ elevation. This was particularly evident in the JFS Canyon Program Area below 5000’ and between the Bear Creek and Devil Creek drainages. • Total snowfall accumulation today while in the field was approximately two inches (2”). | • Below ~6000’ elevation the snowpack has been accumulating snow depth due to new snowfall and wind loading from the east. • Above 6000’ new snowfall and wind loading from the west has been contributing to increased snow depth. • As such leeward aspects (westerly) below 6000’ elevation have been, and continue to be, actively loaded and cross-loaded from moderate easterly winds. • Terrain features in JFS Canyon below 5000’ exhibited enhanced cross-loading on westerly facing aspects. • Above 6000’ southwesterly winds had previously wind loaded easterly aspects. However, southwesterly winds observed today were not actively loading leeward slopes. | • No recent avalanche activity observed but evidence of previous avalanche activity was evident on south/ south easterly aspects above 6000’ elevation. It did appear the Shed 11 path ran within the past few days. Also, other southerly facing terrain adjacent to the SW ridge of Running Rabbit appears to have released naturally as a small soft slab avalanche (D1.5) • We did conduct several ski cuts and cornice drops above 5600’ that resulted in shooting cracks and a small slab that arrested on tree anchors below the fracture initiation elevation. The area that fractured was at approximately 5800’ elevation, a westerly aspect, and the area affected was very small in size. • No other avalanche activity was observed. |
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| 2020-01-11 | 20:43:00 | Burnout to Shed 7 West | Clark | • Conducted road observations from Hwy 2 and toured up the SE ridge of Snowslip Mtn. and into the upper reaches of the Burnout and Shed 4D and on up to Shed 7 West at 6500 feet. Descended the same route. • Objectives were to observe new snowfall totals since Jan 7th, re-assess buried weak layers in this area, and look for any recent avalanche activity. | • Overcast skies with snow showers off/on all day (S-1 to brief S2). Light SW winds all day with very little new wind-loading in our location. • Air temperatures rose to just about freezing on the Canyon floor by this afternoon. Temperatures above 6000 feet rose to the low-20s °F. | • 4-5” of snow overnight with another 1-2” over the course of the day. There was about a foot of new snow since Jan 7th. • Ski cuts on small test slopes resulted in only minor cracking underfoot (1-2 feet long) with no shooting cracks or slab releases. • Re-dug our snowpit in Shed 4D at 5800 feet from the 7th to test the layer of surface hoar that is now buried 30” down from the surface. ECTP14 on this layer on the 7th, ECTN29 on the same layer today. A compression test yielded CT22 SP on this same layer as well. • Continued up into the uppermost starting zone of Shed 7 West and conducted a full profile there at 6500 feet, on a SE aspect, 27° slope. Snow depth was 51” (profile below). No layers propagated in large column tests. A compression test did yield a sudden planar result on the buried near-surface facets sitting on top the Christmas crust down 28” from the surface. • The faceted snow at the base of the snowpack was rounding and unreactive in stability tests. | • Two very small (Destructive size D1.5) storm/wind slabs ran on the steep slope right under the 7 West cornice (about 6700 feet, east aspect). Visibility was limited, but estimate the crowns at 6-8” thick and maybe 40-50’ wide (SS-N-maybe cornice triggered?-R1-D1.5-I). These ran a couple hundred feet down slope terminating well above the rail, entraining a fair amount of snow on the way down. • No other avalanche activity observed. • Could just barely make out the old crowns from the larger (Destructive size 2.5) avalanche that ran earlier in the week. |
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| 2020-01-07 | 19:29:00 | Shed 4D and Burnout | Clark | • Conducted road observations from Hwy 2 and toured up the SE ridge of Snowslip Mtn. and into the upper reaches of the Burnout and Shed 4D avalanche paths to 5800 feet. Descended the same route. • Objectives were to observe the new snowfall totals from the current storm, acquire more detail on the snowpack structure above the rail at the east end of the Program Area, and look for any recent avalanche activity. | • Overcast skies with moderate snowfall for much of the day until about 1600 when snowfall rates began to taper off. Light to moderate SW winds all day with very little new wind-loading in our location. But we suspect wind-loading was more severe above 6000 feet. • Air temperatures rose to just above freezing on the Canyon floor this morning and hovered there all day. Temperatures above 6000 feet rose to the mid to high-20s °F. | • Snowfall totals from the past 2 days ranged from 12-18 inches on the Canyon floor with about 1.2 inches of water equivalent. Above 5500 feet new snowfall has exceeded 20 inches. • From the Canyon floor up to about 5500 feet the new storm snow was “upside down” with heavier, more dense snow from last night and today sitting on top of a layer of lighter, lower density snow beneath. Above 5500 feet this layering structure dissipated and new snow density was more uniform. • Ski cuts on small test slopes resulted in only minor cracking (1-2 feet long) or no shooting cracks or slab releases at all. • We dug a snowpit and conducted a full profile in the upper reaches of the Shed 4D path at 5800 feet on an easterly aspect, 27° slope. Total snow depth was 70 inches with about 24 inches of new snow since yesterday afternoon (pit profile below). • We found an obvious layer of buried surface hoar down 27 inches from the snowpack surface. This layer propagated in an Extended Column Test, ECTP14. • The Christmas crust was about 40 inches down and the November crust was not present at this location. • The faceted snow at the base of the snowpack was rounding and unreactive in large column tests. A deep tap test resulted DT17 with a non-planar break, just below the Christmas crust. | • Path 1163 ran sometime earlier today. Visibility was limited, but the debris ran about 2/3rds path terminating above the rail. This appeared to be a soft slab and was a Destructive size 2 of 5 (could bury, injure, or kill a person). • Numerous small (Destructive size 1) sluffs were observed on steep cutbanks below 5000 feet. • We saw what appeared to be a crown from a recent slab on western side of Shed 5 but could not confirm due to low visibility. |
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| 2020-01-06 | 23:30:00 | Shed 10 | Steiner | • Toured up the SE ridge of Running Rabbit Mtn and into the upper reaches of Shed 10 and descended down and out the Shed 10 Path. • Objectives were to observe the snow surface before today’s storm, acquire more detail on the snowpack structure in this area, and look for any recent avalanche activity. | • Light snow picking up to moderate snowfall (S2) by 1400. Light to moderate SW winds all day with very little new wind-loading. • Air temperatures near freezing on the Canyon floor and warming from the high-teens into the low to mid-20s °F by the afternoon above 6000 feet. | • This morning the Program Area had picked up a trace to 2 inches of new snow since last Saturday, January 4th. From early afternoon till 2300 yesterday there was about 8 inches of new snowfall on the Canyon floor and our upper elevation weather stations were reporting 8-10 inches. • We found sugary faceted snow above a crust or old wind board buried on Christmas Eve and surface hoar under about 8-10 inches of snow that fell during the New Year’s storm on southeast, east, and northeast aspects between 5,200 and 7,050 feet. • Above 6200 feet small test slopes were unreactive to ski cuts. | • Intentionally triggered 4 very small (Destructive size 1) slab avalanches between 6200-5200 feet in the Shed 10 Path. Associated debris ran only a short distance terminating well above the rail. • The soft slabs broke at our feet on ski cuts and ranged from 4" to 1' thick and F to 4F hard. Failure was on the facets above the 12/24 crust, the facet/rain crust 12/31 interface, and an old wind board/facet 12/31 interface. Bed surfaces were the 12/24 crust or 12/24 wind board. A few small sluffs ran from ski cuts where there was no slab and the snow was unconsolidated. • No other avalanche activity observed. |
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| 2019-12-30 | 19:04:00 | Shed 10, Path 1163, Shed 11 | Clark | • Toured through the upper elevations of Shed 10, Path 1163, and Shed 11 today • Objectives were to observe snowpack surface conditions prior to tomorrow’s forecasted snow, obtain some baseline data from Shed 10 and 1163, and re-do stability tests in Shed 11 at same location as the Dec 23rd snowpit. | • A cloud deck of stratus clouds hung around all day from about 5000-7000 feet elevation. Skies were clear above this till late afternoon when some upper elevation clouds began moving in. • Winds were calm or light from the southwest and no precipitation all day. • Air temperatures were in the high-teens to low-20s °F above 6000 ft. elevation this afternoon and warmed to the mid-20s °F at the Canyon floor. | • Below 5000 feet there is little to no snow on sunny slopes. In the shade snow depths range from 3-8 inches. • From 5000-6000 feet the snowpack gradually thickens to about 1-2 feet deep. It’s capped with a stout and usually supportable crust from last week’s warm-up. On top of the crust there’s an inch or two of near-surface facets topped with a new crop of surface hoar (5-10 mm). • From 6000-7400 the snowpack varies from 1-5 feet deep. Last week’s crust becomes breakable and pretty thin by 7200 feet, but still present on sunny aspects. Snow surface is composed of a few inches of near-surface facets and some impressive surface hoar (5-10 mm) • The Program Area has received only trace amounts of new snow over the past week. • One of the most notable observations today was the surface hoar growth. It’s widespread above 5000 feet elevation and found on all aspects. That and the faceted basal layers appear to be gaining some strength. • Dug a test pit in the upper reaches of Shed 10, 7030’, east aspect, 30° slope. Snow depth=62 inches with a poor snowpack structure consisting of a 1F-P hard slab sitting on top of a crust/facet/crust layer combo at the base (pit profile below). No propagation with an Extended Column Test. A Deep Tap test on the bottom layers yielded DT22, BRK, 2 inches from the ground. • Second snowpit and full profile dug in the upper reaches of 1163, a steep, rocky, wind-affected location at 7260’, SE aspect, 38° slope. Snow depth=37 inches with a poor snowpack structure and the same crust/facet/crust sandwich at the base (pit profile below). No propagation with an Extended Column Test. Sudden collapse in the layer of rounding depth hoar at the base of the snowpack, CT18 SC with a Compression Test. • Re-visited the site of our snowpit/profile from Dec 23rd in the Shed 11 path. Extended Column Test then yielded ECTP11 and ECTP13 on the basal facets. Today, ECTN25 on this same layer. | • No avalanche activity observed. | |
| 2019-12-23 | 21:15:00 | Shed 11 | Steiner | Toured up and descended the Shed 11/ Shed 10.7 ridge to the Shed 11 starting zone area (~6300 feet a.s.l.). Objective(s) today focused on getting a good view of recent avalanche activity on the northerly aspect of Mount Furlong and to observe the maximum runout elevation (terminus elevation in the “Broken Bridge” avalanche path. Our secondary goal was to observe snowpack conditions and in the Shed 11 area as well as conduct a full profile at the starting zone elevation of Shed 11. | Skies alternated between broken cloud cover to fully overcast with occasional very light snowfall (S-1). Winds were mostly calm with occasional light gusts from the west. Air temperatures were in the upper 20s and 30s °F at all elevations. | • Snow cover is sparse below 5200’ elevation. Rain affected snow surface to elevations above 6000 feet a.s.l. • No active wind-loading observed. • No collapsing, shooting cracks, or audible failures experienced. • Full profile conducted at 6369’ on a southerly aspect, 26-degree slope. • Snow depth 24 inches at profile location. • Stability Test (Extended Column Test) results: Test 1: ECTP11 @4.5 inches from ground surface on top of a layer of rounding facets (Snappy!). Test 2: ECTP13 @4.5 inches from the ground on the same facet layer. | • No new avalanche activity observed. However, we did observe maximum runout elevation of the Mt. Furlong (outside the Program Area, located across Hwy 2 on the Flathead Natl. Forest) avalanche and it appears it terminated at approximately 6000’ a.s.l. (photo). | |
| 2019-12-13 | 21:00:00 | Shed 7 | Clark | • Toured through the upper elevations of Sheds 7 East, 6, and 5 today. • Objectives were to look for any recent avalanche activity, measure new snow accumulations, assess recent wind-loading, and continue to monitor snowpack structure and stability. | • Overcast skies with light to moderate (S1 or S2) snowfall off and on throughout the day with moderate SW winds above 5000 ft. elevation. • Air temperatures hovered in the low to mid-20s °F above 6000 ft. elevation and warmed to low-mid 30s °F at the Canyon floor by early afternoon. | • New snow accumulations from the past two days range from 8-11 in. on the Canyon floor to 12-18 above 6000 ft. elevation. • Above 5500 ft. the snowpack is about 1-2 ft. deep and above 6000 ft. deepens to 3-4 feet in wind sheltered areas. Wind loaded areas were deeper with up to 5 or 6 ft of snow in some locations. • Fresh wind slabs on easterly aspects were up to 1 ft. thick above 5000 ft. Ski cuts through these wind slabs resulted in some shooting cracks up to 50 ft in length (photo below). • Observed only one small avalanche in Shed 7 West, details below. • Revisited the same location in the Shed 7 East path where a full snow profile was conducted at 6300 ft. on a SE aspect on Dec 2nd. The snow depth here has doubled over the past 11 days from 24 to 50 in. No fractures during an extended column test on the layer of facets now buried 40 in. down in the snowpack. This facet layer was also moist from last week’s warm weather and had firmed to 4F+ hardness. • Dug another snowpit nearby at 6400 ft on an ENE aspect. Total snow depth was 40 in. with moist but weak facets making up the bottom 6 in. An extended column test resulted in ECTP21 on this weak basal layer (snowpit profile below). | • One small (SS-NC-R1-D1.5) in the Shed 7 West path at about 6700 ft on an E aspect. Looked to be a cornice fall trigger that cut out a recent wind-slab just below the ridge crest. Estimated slab thickness was 5-10 in. with debris running only a couple hundred feet terminating well above the rail grade. | |
| 2019-12-02 | 15:45:00 | Shed 7 | Clark | • Toured through the upper elevations of the Shed 7 East, Shed 7 West, and Shed 5 avalanche paths. • Objectives were to observe snow depths and snowpack structure above the railway grade as the 2019-20 winter snowpack continues to develop. | • Overcast skies with very light or light (S-1 or S1) snowfall all day with moderate SW winds above 5000 ft. elevation. • Air temperatures hovered in the low to mid-20s °F above 6000 ft. elevation and warmed to just above freezing at the Canyon floor by early afternoon. | • Snow depths around 5000 ft. elevation varied between 10-15 inches and above 6000 ft. typically ranged between 1-2 feet. Previous wind transport from last week’s N-NE winds was notable on S-W aspects, especially above 5000 ft. with old wind slabs up to 3-4 ft. thick in exposed locations such as the Shed 6/7 ridge. • New wind slabs from today’s SW winds were still relatively small, about 6-8 in. thick and generally less than 20 ft. across. • Ski cut one small new wind slab, 6-8 in thick x 10-15 ft. wide on a SE aspect slope at about 5500 ft. • Conducted a full snow profile at 6300 ft. elevation, SE aspect, in the very upper reaches of the Shed 7 East avalanche path (photo of profile below). • Total snowpack depth at profile location was 24 in. The snowpack structure was poor with a cohesive slab capping a layer of weak facets sitting on top of a firm melt-freeze crust. • Stability tests resulted in: ECTP22 on this layer of facets about 13 in. from the snowpack surface (1st test) ECTN23 on the same layer of facets but fracture propagated across only half the column (2nd test). | • Save for the one very small ski cut wind slab mentioned above, no avalanche activity observed. | |
| 2019-03-20 | 23:00:00 | Sheds 11 & 10.7 & Road Obs JFS Canyon | Clark | • Observations from Hwy 2 in JFS Canyon. • Also completed a short tour into the lower reaches of the Shed 11 and 10.7 paths to better document the avalanche activity there. | • Clear skies overnight and all day. Calm or light and variable winds. • Air temperatures were inverted this morning with readings in the low 20s °F at the Canyon floor and the high-30s to low-40s °F above 6000 feet. Daytime highs today reached the low-60s at the Canyon floor and the mid-50s °F at upper elevations. | • Another round of avalanching with a trend towards more slabs and larger, more destructive avalanches that are running longer distances. • Multiple size D2 avalanches in the Program Area and in nearby locations on sunny aspects. • Also at least a couple size D3 slides. • Some of the new activity observed since early yesterday afternoon includes: o Shed 11, ran late yesterday afternoon, wet loose triggered a slab, size D3 and ran ¾ path o Shed 10.7, ran late afternoon, wet loose and possible slab, size D3 and ran most of the path terminating within 100 yards of the shed. o Path 1163, multiple point releases and possible slabs including a D2.5 clearing out most of the looker’s right lower headwall, debris ran ¾ path terminating above the rail grade. o Shed 10, multiple point releases in the feeder path and the looker’s right headwall with a large slide occurring this afternoon. Debris terminated above the rail. o Looker’s right headwall in Grizzly Gulch, wet loose triggered slab, size D2 at least. o Infinity, multiple releases, debris has been terminating about 200 yards above the rail grade. o Size D2 avalanches on the west face of Running Rabbit above Hwy 2 (does not threaten railway). Debris terminated well above the Hwy. • Lower angled paths with a deeper snowpack such as Shed 7, upper Shed 8, and upper Shed 9 still have had minimal to no activity. • Please see the 2nd PDF attachment: March19-20_2019_AvalancheActivity for photos. |
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| 2019-03-19 | 17:16:00 | Shed 7 & Road Obs JFS Canyon | Clark | • Travelled up the Shed 6/7 ridge to the Shed 7 weather station then up to the Snowslip weather station. • Descended the Shed 7 W path • Also drove a couple times along Hwy 2 in JFS Canyon to view and document recent avalanche activity. | • Clear skies overnight and all day. Calm or light and variable winds. • Air temperatures were inverted this morning with readings in the high teens to low 20s °F at the Canyon floor and the low-30s °F above 6000 feet. At 1630 it is pushing 60°F here in Essex and has warmed to the high-40s to low-50s °F up in our high elevation terrain. | • Last night’s supportable melt freeze crust began breaking down on sunny slopes around 10 am. • Ski penetration on the way out via Shed 7 W was only about 4-6” above 5000 feet. Became quite punchy below there in a much shallower snowpack that is primarily composed of wet facets at this point. • Quick pit at 6400 feet on a SE aspect in Shed 7 West. Snow depth=60” with the upper 6” moist but still cold, dry snow below that to the ground. Top 16” was 4F hardness with 1F hardness below that to the bottom • Stability tests: ECTX and CTN. • Large cornices exist in the Shed 7 West and Infinity paths. No chunks had broken off yet as of 1500. | • Wet loose avalanches continue to step down into deeper layers in the snowpack and in some instances are gouging down to the ground. • In a few cases (Infinity & 1163) wet loose debris had triggered small slabs releasing on deeply buried weak layers (photos) • The majority of activity is on steep, rocky slopes with sunny aspects and a shallow and weak faceted snowpack. • Some of the new activity observed since yesterday includes: o Shed 10 Feeder path, ran yesterday and this afternoon, D2.5, debris term. ¾ path above rail o Shed 8, looker’s L & R lower headwalls, ran yesterday, D1.5s, debris terminated above rail o Infinity, ran yesterday D2, and early this afternoon D2.5, debris terminated ¾ path above rail o Path 1163, multiple point releases mostly on the looker’s L upper headwall today, D2s, debris ran ¾ path terminating above the rail grade. • Lower angled paths with a deeper snowpack such as Shed 7, upper Shed 8, and upper Shed 9 have had minimal activity with only small wet loose confined to the upper few inches of snow. |
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| 2019-03-18 | 16:00:00 | Road Obs. JFS Canyon | Clark | • Road observations and short tour up the rail to the bottom of Jakes and Infinity. | • Clear and sunny. Calm or light and variable winds • Air temperatures inverted in the AM - low to mid-20s °F at the Canyon floor and high-20s °F above 6000 feet. By 1600 temps in the low-50s °F at the Canyon floor and mid-40s above 6k. | • The snowpack was solidly locked down this morning with a supportable crust extending above 7000 feet. Winds were calm, or light and variable above 6000 feet (off duty tour up Elk Mtn in the morning). • Steep E-SE aspects were starting to soften by 10 am and wet loose activity began again around noon. Around 1 pm another D2-size wet loose had run in Path 1163. | • Widespread wet loose avalanche cycle over the weekend in JFS Canyon on the steep and sunny slopes above the railroad. The action continues today... • Observed dozens of D1-D2 avalanches that ran over the weekend. Initiating mostly on steep terrain and near rock outcrops and cliff bands but at all elevations between 4000-7000 feet. • Noted how deep some of the avalanches were running in the near-surface faceted snow formed last month. At low-mid elevations some larger slides were even gouging deeper, nearing 2 feet in depth and removing most of the season's snowpack. • In at least one instance some wet loose debris released a few narrow slabs as it moved downhill (photo). • In the larger paths with activity such as Shed 10 and 1163 total debris runout exceeded 2000 vertical feet. Path 1163 already has a well-defined runnel down the gut. • Lower angled paths such as Sheds 7 & 8, and the uppermost reaches of Shed 9 had limited activity. |
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| 2019-03-05 | 22:00:00 | Path 1183/Wahoo Ridge | Clark | • Travelled to the NW end of our Program Area and checked out avalanche Path 1183 which is the NE-facing unnamed drainage between Wahoo and Cascadilla Creeks. Ascended the ridge separating Path 1183 and Cascadilla Ck, traversed the top of the path with a quick stop for snow pit/profile, then descended into Wahoo Ck for the exit. • Objective was to observe the snow structure and check out the wind-loading from all the recent NE winds. | • Mostly sunny skies with no precipitation and calm conditions and no wind-loading today. • Air temperatures warmed into the low to mid-20s °F by the end of the day. | • No collapses, cracking, or any other signs of instability observed. • Previous wind transport was notably less severe at the low-mid elevations here than in JFS Canyon. • Most notable was how much the upper snowpack has faceted due to the recent cold temperatures. Skinning was often tedious providing a great workout today. • We conducted a snow profile at 5600 feet elevation in Path 1183 on an easterly aspect. • Total snowpack depth at profile location was 93 inches. We dug to just below the Groundhog Day crust, about 43 inches from the snowpack surface (see profile below). • The facets around the Groundhog crust were un-reactive in our stability tests. • Stability tests resulted in: ECTN11 and CT10 Q3, 12” from the snowpack surface CT23 Q2, 20” from the snowpack surface on a thin layer of facets. | • Visibility was excellent and we observed no recent avalanche activity in our vicinity. | |
| 2019-02-28 | 17:00:00 | Sheds 7 & 8 | Steiner | • Toured up the Shed 7/8 ridge to the southwesterly aspect near the starting zone of Shed 8. • Objective was to observe the snow structure after the recent cold temperatures and winds. Specifically wanted to observe the wind-loading on more westerly-southerly aspects that have recently been loaded by northerly/northeasterly winds. • Conducted full-snow profile on a southwesterly aspect at 6100 feet elevation near the starting zone of Shed 8. Profile was conducted on a 37 degree slope. | • Overcast skies with intermittent S1 snowfall and mostly calm conditions. • Air temperatures were in the teens and twenties 0F throughout the day at all elevations. | • No collapses or cracking observed. • Substantial recent windloading on southerly and southwesterly aspects above 5400 feet elevation. • Snow profile conducted on a 37 degree slope at 6100 feet elevation in Shed 8 and on a southwesterly aspect. • Total snowpack depth at profile location was 52 inches. • All layers in this snow profile location consisted of facets or rounding facets. Main concern at this location was a 1+ inch thick layer of .04-.08” (1-2 mm) facets above The “Groundhog Day” Crust. . The Ground Hog Day crust at this location was buried approximately 30 inches (75 cm) from the snowpack surface and was approximately 3/8 inch (1 cm) in thickness. • Stability tests resulted in: ECTN117x1@ 24” from the snowpack surface on facets just above the Groundhog crust ECTN 23x1@ 4’ from the snowpack surface (In well-developed basal facets). | • No recent avalanche activity observed. | |
| 2019-02-19 | 17:00:00 | Sheds 5, 6, 7 | Steiner | • Toured up the Shed 6/7 ridge to the Shed 7 East Weather Station for a welfare check. • Cleaned weather station solar panel and descended terrain adjacent to the Shed 5 Path. • Excavated a test snow profile on a SE aspect at 5400 feet. | • Mostly cloudy skies with a solid, snow transporting south westerly wind. • Air temperatures were chilly at all elevations and remained in the single digits 0F throughout the day. | • Active windloading on easterly aspects above 5200 feet elevation. • No collapses or cracking observed during the tour. • Snow profile conducted on a 34 degree slope at 5400 feet elevation on a southeasterly aspect. • Total snowpack depth at this location was 60 inches. • Prominent facet/crust interfaces at this profile site consisted of: The newly established “Valentine’s Day Crust (0.5” thick and 9” from snowpack surface). The “Groundhog Day” Crust (7” thick and buried 28” from the snowpack surface). The 1/17/19 Crust (1.5” thick and buried 36” from the snowpack surface). • Stability tests resulted in: ECTP10x1@ 8” from the snowpack surface ECTP17x1@ 28” from the snowpack surface (On top of the GHD Crust. ECTP 26x1 @ 41” from the snowpack surface. (This was beneath the 1/17 crust) This ECTP result was repeated but with hard force and “33” taps (blows). • Facets beneath the 1/17/19 crust remain well preserved and .08” to 0.11” (2-3 mm) in size. | • Evidence of older slab avalanche activity in Test slope 1 with a southeasterly aspect at 5200 feet elevation and Test Slope 2 also with a southeasterly aspect at 5400 feet elevation. • No recent avalanche activity observed. |
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| 2019-02-15 | 19:50:00 | Shed 11 | Clark | • Toured up the SW ridge of Running Rabbit Mtn. Followed ridge to avalanche prone terrain above Shed 11 to the weather station and descended the same. • Objective was to assess the recent storm slab instability and get a snowpack profile or two in the Shed 11 area. | • Broken skies with occasional S-1 snow flurries. But dry weather for most of the day. • Air temperatures climbed into the mid-20s 0F above 6000 feet and near freezing at the Canyon floor. • Winds mostly calm but occasion light breeze from the W-NW. | • Feb 12/13 storm slab had settled to 12-16” thick and 4F hardness. About 2-3 inches of snow from last night on top of this. • Put in numerous ski cuts with no cracking or small slabs popping out on small test slopes. • No collapses or cracking at any other points during the tour. • Dug a pit at 6300 feet on a southerly aspect. Total snow depth was a little over 6 feet. The Feb 2/Groundhog crust was very thin at this location, but the widely distributed (in the Program Area) layer of facets beneath the crust was there (profile below). • Stability tests resulted in ECTN26 and CT22 Q2 at the bottom of the Feb 12/13th storm slab about 18” from the surface. No fractures on the Groundhog or Jan 17 crusts. • Dug a 2nd pit at 5500 feet also on a south aspect. Here the Groundhog Day crust was buried 12 inches down and almost 2 inches thick. • Found an almost 8 inch thick layer of well-developed facets lying beneath the Groundhog crust here, ECTP27 on this layer. | • No recent avalanche activity observed. | |
| 2019-02-12 | 22:15:00 | Shed 4D/Burnout | Clark | • Toured up Burnout to the southeast shoulder of Snowslip Mountain. Followed ridge to avalanche prone terrain above Shed 4D. Descended Shed 4D ridge back to Burnout. • Objective was to conduct snow profile in the mid-elevation terrain of Shed 4D and also ski cut numerous convex rolls at mid and lower Program Area elevations to observe interaction of new snow on old snow surfaces. | • Light to moderate snowfall throughout the day with periods of heavy snowfall. • Skies were overcast all day with air temperatures climbing from the single digits 0F to upper 20s 0F. • Sporadic light to moderate southwesterly wind. | • Feb 12th storm totals: Essex at 2100, 14”, Java East at 1900, 15”, Devil Creek at 1440, 12” • At time (1230) of our profile observation (@5800’) Height of New Snow (HNS) was 14”. • Snow structure of new snow was slightly upside down with heavier new snow deposited on lower density snow. • This new snow character promoted easy sluffing on tour and isolated cracking within the new snow. • Snow profile was conducted on a 30 degree slope with an easterly aspect. • Profile depth was six feet (6’) with a relatively supportive structure except for the new snow- old snow interface located 14 inches from the snow surface. • Stability tests resulted in an ECTP5 at 14” from the snow profile surface and a couple ECTN results deeper in the snowpack on the Feb 2nd and Jan 17th crusts. | • No substantial avalanche activity observed. However, numerous, very small storm slabs were observed on various aspects throughout the day on slopes steeper than 35°. Slab thickness varied between ~4” and ~6.” | |
| 2019-02-08 | 21:30:00 | Shed 9/Infinity/Shed 7 W | Clark | • Toured up the Infinity/Shed 9 ridge on the south face of Snowslip Mtn. and traversed over to the top of the Shed 7 W path. Descended Shed 7 W back to the Hwy. • Objective was to investigate the avalanche that ran in the Infinity path last Tuesday (2/5). The crown was mostly blown back in with new snow and we could not safely reach the location of the avalanche. But dug a pit and profile (see below) about 50 yards east of the site. • Also wanted assess the most recent wind loading. | • The Arctic front arrived a bit earlier than expected. By late morning temperatures were dropping and winds had clocked from the W to the NE and were increasing in speed. • Very light snowfall most of the day with overcast skies in the AM and broken skies by early afternoon. • Moderate NE winds were lightly loading westerly aspects at all elevations. | • Only about 1-2 inches of new snow in the past 24 hours. • The NE winds were forming thin new slabs primarily on S-SW-W aspects at all elevations today. • These new slabs were actually more reactive at low-mid elevations. Ski cut one very small slab, 6” thick x 12’ wide at about 5000 feet (photo below). • We dug a snowpit and conducted a full snow profile on a south aspect at 6200 feet elevation on the ridge immediately to the east of the Infinity path (pit profile below). • Still not certain what the weak layer/failure plane was for the Feb 5 Infinity avalanche. But we suspect a layer of surface hoar that formed in mid-January and was buried about 2 feet below the surface at the pit location. • Cornices in Infinity, Shed 9, and Shed 7 were eroding back into the slope by the wind. | • No avalanche activity observed since Tuesday February 5th. | |
| 2019-01-30 | 23:30:00 | Sheds 7/5 | Clark | • Toured up the Shed 6/7 ridge on the south face of Snowslip Mtn. to the Shed 7 weather station and just above there to about 6600 feet elevation. • Objective was to assess the snow surface conditions, recent wind-loading, and keep tabs on the weak layers in the snowpack (mid-Jan SH/facets/crust and early Dec facets). • Descended the Shed 5/4D area. | • Mostly sunny in the AM becoming mostly cloudy by the afternoon with no precipitation all day. • Moderate westerly winds were only lightly wind-loading the easterly aspects in our location. On sunny aspects the surface was slightly crusted/firmed up from the past couple days and this limited the wind-loading. Although on some nearby peaks we could see more intense wind-loading (photo below). • Air temperatures reached the high-20s °F at the Canyon floor and into the high teens/low-20s °F above 6000 feet. | • New crop of surface hoar growing on the snow surface on most all aspects and elevations. This is being destroyed by the winds at exposed locations above 5000 feet. • We found buried surface hoar on top of the mid-January crust in locations more sheltered from the wind between 5000-6000 feet. • We dug a snowpit and conducted a full snow profile on a SE aspect at 5600 feet elevation on the Shed 5/4D ridge. Total snow depth here was 57 inches and we found a gray stripe of buried surface hoar 20 inches down from the surface. This layer fractured but did not propagate during an Extended Column test. We did a get a propagating result on a thin layer of facets about 8 inches down from the surface (pit profile below). • The early December facets at the bottom of the snowpack were unreactive at the snowpit location • No shooting cracks, sudden collapses, or small slabs running on test slopes while ski cutting. | • No recent avalanche activity observed. • Evidence of older cornice fall and small slab avalanches in Shed 7 W, most likely occurred over the weekend. |
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| 2019-01-22 | 22:00:00 | Shed 7 | Clark | • Toured up the Shed 6/7 ridge on the south face of Snowslip Mtn. to the Shed 7 weather station and just above there to about 6500 feet elevation. • Objective was to assess the Jan 21 storm snowfall totals and see how this and last week’s storm snow was bonding to the pre-storm surface. Also continue to keep tabs on the weak snow at the bottom of the snowpack. | • Cloudy skies with intermittent snow showers, S-1 intensity picking up to S2 by later afternoon. • Air temperatures in the teens °F above 6000 feet and mid-20s below that. • Moderate west winds above 5500 feet. | • 6-10 inches of new snow from the Jan 20/21 storm. • Fresh wind slabs were forming on easterly aspects above 5500 feet due to the westerly winds. These were mostly thin, 5-8 inches. • These wind slabs were stubborn to ski cuts and we only had minor cracking 3-6 feet in length. • We found buried surface hoar on top of the Jan 17 crust in locations more sheltered from the wind between 5000-6000 feet. • We dug a snowpit and conducted a snow profile on an SE aspect at 5400 feet elevation on the Shed 6/7 ridge. Total snow depth here was 38 inches and we found the December facets at the bottom of the snowpack to be reactive and propagated with hard force in an Extended Column Test (ECT). Pit profile below. • We also found surface hoar buried 12 inches down on top the Jan 17 crust. This layer would fail but not propagate across the column during an ECT. | • No avalanche activity observed. | |
| 2019-01-18 | 23:50:00 | Grizzly Gulch | Clark | • Toured up the Grizzly Gulch between Running Rabbit and Snowslip Mountains to about 7000 feet on the east face of Running Rabbit. • Objective was to assess Jan 17/18 storm snowfall totals and see how this new snow was bonding to the pre-storm surface. Also continue to keep tabs on the weak snow at the bottom of the snowpack. • Descended via the same route taken up. | • We were sheltered from the wind down in the gulch and winds were mostly calm there. We could see and hear the west winds above us. Visibility was limited but we could occasionally see the wind-loading onto easterly aspects near exposed ridgelines. • Air temperatures in the low to mid-20s °F above 6000 feet under mostly cloudy skies with occasional snow flurries. • Snowed another 1-2 inches during the tour. | • Jan 17/18 storm totals were pretty under-whelming in the Program Area, 3-4 inches total at the Canyon floor and 6-8 inches above 6000 feet elevation. • The new storm snow was low density and had not yet formed a cohesive slab in the sheltered terrain we travelled through. But fresh wind slabs were forming above us in locations more exposed to wind. • An approximately one inch thick melt-freeze crust from last week’s warm-up and subsequent sunny/warm weather at upper elevations was present everywhere we travelled underneath the new snow. • We dug a snowpit and conducted a snow profile on an east aspect at ~6800 feet elevation in the basin just below the upper east face of Running Rabbit (pit profile below). Total snow depth here was 87 inches. • Underneath the Jan 17 crust we found a thin layer of well-developed facets which propagated with moderate force during an Extended Column Test. No buried surface hoar at this location. • The early December facets were present at the bottom of the snowpack. These are rounding and we did not get any fractures on this layer during a Deep Tap Test (DTN). | • No avalanches observed today. • No evidence of any large avalanches that have run to the bottom of the gulch earlier this year. |
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| 2019-01-09 | 16:00:00 | Burnout/Shed 5 | Clark | • Visited the Shed 4/Burnout weather station for a welfare check then continued up the SE ridge of Snowslip Mtn. above the Burnout, Shed 4D, and Shed 5 avalanche paths. • Objective was to asses yesterday’s snowfall totals in the eastern end of the Program Area and keep tabs on the snowpack structure, specifically the persistent weak layer(s) near the bottom of the snowpack. • Descended via the same route taken up. | • Warmer air aloft in the morning with temperature near/just above freezing above 6000 feet and in the mid-20s °F below that. By later in the day the cold air pool in the valley had mixed out and temperatures were above freezing across most of the Program Area. Skies were mostly cloudy with occasional light rain, snow, or rain/snow mixed showers throughout the day. Winds were light from the west. | • Only a trace of new snow overnight. New snowfall amounts from Monday’s storm ranged from 8-12 inches. • The upper 6-8 inches was becoming quite dense and heavy due to the warming temps and liquid precipitation. • Recent wind-loading was minimal • We dug a snowpit in the uppermost reaches of the Shed 5 avalanche path at 6000 feet elevation and an east aspect. Total snow depth here was 63 inches. • Wind-loading from earlier in the winter has been more substantial here and below the 13 inches of new snow from Monday we found several generations of wind slabs totaling 3 feet thick and ranging from 1F to P- hardness (photo below). • The poor snowpack structure remains with the December facets present near the ground. We could not get this layer to fail during an Extended Column test, probably due to its depth and the thick, hard slab of snow above it. • However this layer failed with hard force during a Deep Tap test resulting in a non-planar, irregular fracture. | • We observed a few small wet loose snow avalanches (sluffs) on steep terrain above the rail. No debris reached the grade. • No other avalanche activity observed. |
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| 2019-01-08 | 19:00:00 | Shed 10.7 - 1163 | Clark | • Travelled up the south face of Running Rabbit Mtn. via the Shed11/10.7 ridge to the Shed 11 weather station then continued up the SW ridge of Running Rabbit to 7300 feet and looked into the uppermost starting zone of Path 1163. • Objective was to asses yesterday’s snowfall totals and keep tabs on the snowpack structure, specifically the persistent weak layer(s) near the bottom of the snowpack. • Descended via Shed 10.7 and the Shed 10.7/11 ridge | • Clear skies in the AM becoming partly cloudy by the afternoon. No precipitation and almost totally calm conditions. Air temperatures in the low-teens °F above 6000 feet for most of the day. | • New snowfall amounts from yesterday’s storm ranged from 8-12 inches. • The recent wind-loading was much less severe than with previous storms. The newest generation of windslabs were general less than 8 inches thick and mostly isolated to the eastern side of the Shed 11/10.7 ridge. • We could get some minor shooting cracks, 2-4 feet long, in these new wind slabs with ski cuts (photo). • Above 7000 feet where the snowpack was thin and/or variable over the rocky terrain we experienced numerous audible collapses and had some cracks shoot 10-20 feet out from under our skis. • We dug a snowpit on the ridge just west of Path 1163 at 7250 feet elevation on a southeasterly aspect where we heard/felt a collapse. • The poor snowpack structure remains with the December facets present near the ground underneath a firm mid pack of 1F hardness (pit profile below). The December facets remain reactive here and the layer failed and propagated with hard force during an Extended Column Test. | • Visibility was excellent and we saw one small (D1.5) slab avalanche that failed in the Shed 7 West just underneath the cornice (photo). Debris terminated well above the rail grade. • No other avalanche activity observed in the Program Area. • Outside the Program Area in the nearby Flathead range we saw several avalanches including: o Multiple on the E face of Felix Peak, with some likely failing on the Dec facets, up to D2.5 (photo). o 1 on the NE face of Unawah also likely failing on the Dec facets. o 1 below the E col of Adams/Elk Mtn, again suspect the Dec facets as failure layer. o Wind/storm slab on the E face of Cameahwait, D2 |
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| 2019-01-02 | 18:00:00 | Shed 7 | Clark | • Travelled up the south face of Snowslip Mtn. via the Shed7/6 ridge to the Shed 7 weather station then continued up the ridge to 7000 feet and the Snowslip weather station. • Objective was to assess new snowfall amounts along with the recent wind,-loading. Also needed to keep investigating the snowpack structure, specifically the persistent weak layer(s) near the bottom of the snowpack. • Descended via Shed 7 West. | • Overcast skies, with intermittent S-1 snowfall and moderate to strong west winds near the ridge crests. Air temperatures were in the 20s °F above 6000 feet elevation for most of the day. | • The snowpack is finally deep enough to ski from the rail grade. Our manual weather/snowpack measurement stations in the Canyon both show about 14 inches of snow on the ground. Essex has 23 inches. • Above 5500 feet elevation moderate to strong westerly winds were actively loading east aspects. Still we observed few signs of instability other than a few minor shooting cracks running only about 2-4 feet. • The cornices above Shed 7 West that were almost fully eroded earlier this week by east winds are now re-building due to the recent snow and steady westerly winds. • We dug a snowpit in the upper reaches of Shed 7 West at 6650 feet elevation on as easterly aspect (pit profile below). The poor snowpack structure remains with the December facets present near the ground underneath a firm mid pack of 1F hardness. The first Extended Column Test resulted in ECTX, the second in ECTN16 on a density change between layers about 16 inches down. | • One small (D1.5) slab avalanche triggered by a falling cornice ran about 700 vertical feet from the top of Shed 7 West. This debris terminated in the upper 1/3rd of the avalanche path. • No other avalanche activity observed. |
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| 2018-12-26 | 23:30:00 | Shed 10.7 | Clark | Travelled up the south face of Running Rabbit Mtn. via the Shed10.7/11 ridge to about 7200 feet to assess the snowpack structure, specifically the persistent weak layer(s) at upper elevations. Descended via the same route. Still had to walk below 4800 feet due to lack of snow. | Mostly cloudy skies, with intermittent S-1 snowfall and mostly calm winds. Air temperatures were chilly, hovering around 10-15 °F above 6000 feet elevation for most of the day. | • The snowpack is still quite shallow for this time of year but depths increase quickly to about 2-3 feet above 6000 feet elevation. • We experienced a couple audible collapses on layer of facets and/or a facet/crust/facet layer combo that lurks near the bottom of the snowpack. • The first collapse was at about 7000 feet on a south aspect and the second was a quite loud and lengthy rumble across an entire 200+ foot wide slope at 7200 feet also on a south aspect. • We originally planned to traverse into Path 1163 but due to the unnerving collapse and with steeper/more exposed terrain waiting ahead, we backed off our route and dug a snowpit in the uppermost reaches of the Shed 10.7 path instead. • Two Extended Column tests in that snowpit (7200 feet, south aspect, 30° slope) resulted in propagation with moderate force on top of a layer of facets, buried about 20 inches down in this location. See pit profile and picture below. | • No avalanche activity observed on the tour or anywhere in JFS Canyon. | |
| 2018-12-19 | 23:30:00 | Shed 7 East | Clark | Travelled up the Shed 6/7 ridge to the Shed 7 East weather station at 6300 feet to assess yesterday’s storm totals and to check out the instability associated with the weak basal facets we observed last week. Descended via a nice tour through the Sheds 4, 5, 6, region and finally back to the Shed 6/7 ridge in an effort to find snow deep enough to ski. Still had to walk below 5400 feet. | Mostly cloudy skies, with intermittent S-1 snowfall, and light to moderate southwesterly winds. Air temperatures in the 20s °F above 5500 feet. | • Below 5500 feet there is still generally less than 25 cm of snow on the ground. Above that elevation snow depths quickly increased and yesterday’s storm totals ranged from 20-30 cm. • The new storm slab was less reactive than expected and the recent wind loading was much less prominent compared to last week. • We experienced a couple audible collapses on the basal facets during our tour. • Two Extended Column tests in a pit at 6400 feet on an east aspect resulted in propagation with moderate force on top of the basal facets, buried about 50 cm down in this location. See pit profile and picture below. | • No recent avalanche activity observed on the tour or anywhere in JFS Canyon. | |
| 2018-12-13 | 23:30:00 | Shed 7 East | Clark | Travelled up the Shed 6/7 ridge for a welfare check on the Shed 7 weather station and to assess stability now that our weak, pre-storm snowpack was recently buried by a slab. In general, where a snowpack existed, which was mostly on easterly aspects above 5500 feet elevation, stability was poor and we intentionally triggered one avalanche at about 5600 feet elevation. | Mostly cloudy skies, S-1 snowfall, and moderate to strong westerly winds that were actively loading easterly aspects. Air temperatures in the 20s °F above 5500 feet. | • Below 5500 feet there is still generally less than 25 cm of snow on the ground. Above that elevation snow depths quickly increased and ranged from 50-150 cm above 6000 feet elevation. • Above 5500 feet there were touchy wind slabs on the east-facing slopes. We observed many signs of instability such as audible collapses, shooting cracks, and avalanches. • In some exposed locations above 6000 feet the wind-loading has been heavy and we estimate there are locations with new wind slabs well over 1 meter thick. • Extended Column tests in a pit at 6200 feet on an east aspect resulted in propagation on the new storm snow/old snow interface (top of the facets) about 35 cm down and also on another layer of facets about 60 cm down from the surface. | • Intentionally triggered a wind slab avalanche by walking near the flank. Failure was on the facets just below the base of the wind slab, new snow/old snow interface. Location was at 5600 feet and SE aspect in a location known as Test Slope 2. Avalanche classified as HS-AF-D1.5-R4-I, crown ranged from 20-50 cm thick and about 30 m wide. Debris ran about 50-70 m down the slope. Photos below. • No naturally releasing avalanche activity was observed save for some cornice fall at the top of Shed 7 West. |
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| 2018-11-08 | 10:30:00 | Shed 10.7/11 | Clark | Went on an early season hike yesterday to work on the Shed 11 weather station and to check out the developing snowpack. Travelled up and down the ridge that divides the Shed 11 and Shed 10.7 avalanche paths on the south face of Running Rabbit Mountain. Our high point was the weather station at 6400 feet. | Mostly cloudy skies, no precipitation, and light NW winds. Air temperatures hovered in the high-teens °F above 6000 feet. | • No real avalanche concerns at this time as the snowpack is still quite thin. • Below 5500 feet there was typically less than 15-20 cm of snow on the ground. Above that elevation snow depths increased to 25-40 cm. Snowpack consisted mostly of low-density soft snow. • Found a few very small, isolated wind slabs on exposed locations along the ridge. These were typically 50-80 cm thick and un-reactive – no cracking or any signs of instability. • Definitely need more snow before we’ll be skiing in the Program Area. | • No recent avalanche activity observed. • No avalanche concerns at this time. |
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| 2018-04-03 | 16:15:00 | Shed 10.7/11 | Clark | • Toured up the ridge separating the Shed 11 and Shed 10.7 avalanche paths. Worked on the Shed 11 weather station and then descended the Shed 10.7 path back to the rail grade. | Skies were overcast with S-1 to S2 snowfall all day. Air temperatures were in the low 20s °F at upper elevations and near freezing at Canyon floor elevations. Calm winds at the Canyon floor and light west winds above 5000 feet elevation. | • Since the weather turned cold and snowy last Friday (3/30) another 25-30 cm of snow has accumulated on top of supportable melt-freeze crust on the Canyon floor. • Above 6000 feet elevation we found 30-50 cm of recent snowfall on top of the latest melt-freeze crust. • East winds from over the weekend had formed wind slabs on westerly aspects. These were unreactive to ski cuts. • Today’s west winds were mostly light and we saw very little blowing snow. • We could sometimes trigger small sluffs on steep rollovers, but loose snow avalanche activity was minimal. | • Observed less than a dozen very small (D1) loose dry avalanches on steep slopes. • No slab avalanche activity observed. |
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| 2018-03-13 | 22:10:00 | Shed 10 to Shed 7 | Clark | Ascended the Second Slide avalanche path on the south face of Running Rabbit mountain and continued onward to the Running Rabbit/Snowslip Ridge. Continued east, then southeast to the Snowslip weather station and descended the Shed 7 West avalanche path. | Mostly clear skies all day with no precipitation and light SW winds. Temperatures in the morning were inverted with values in the mid-teens °F at the Canyon floor but near freezing above 6000 feet elevation. By the afternoon, temperatures ranged from the high-30s to high-40s °F above 6000 feet elevation and into the low-50s °F at the Canyon floor. | • Solar aspects have now undergone a few melt-freeze cycles and the associated surface crust has thickened to a few cms to almost 20 cm in some locations. • This crust helped to keep wet loose avalanching and rollerball activity to a minimum this afternoon. • Meanwhile on shady aspects there is still cold powder snow with a healthy crop of surface hoar growing on the top (photo 1). • Overall we found mostly stable snow with only a couple of small wet loose avalanches running today on the steepest slopes on sunny aspects. • That being said, we avoided these steep sunny slopes, but suspect ski cuts could have easily triggered some wet loose avalanches. | • One small (D1.5) wet loose ran today in the Infinity avalanche path. Debris ran 1/3rd path. • Chunks of the Shed 7 West cornice have broken off with debris running ½ path. • A larger chunk of cornice fell off the summit of Running Rabbit (east aspect) sometime in the past couple of days (photo 2). • No slab avalanche activity observed. |
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| 2018-03-02 | 08:30:00 | Burnout | Steiner | • Toured up the looker’s right side of the Shed 4C “Burnout’ avalanche path to the upper easterly aspect of the Shed 4 starting zone. • Excavated three different test profiles (profiles) between the Burnout avalanche prone starting zone and Shed 4. Profiles were examined and ECT stability test(s) were conducted in starting zone terrain located at 5800, 5500, and 5300 feet elevation (a.s.l.). • Focus of each profile was observing the strength of the February 8th melt-freeze crust (crust) and interface conditions with faceted snow layers above and beneath the crust. • Profile slope angles averaged 30 degrees and aspects ranged between east and southeast. Descended same route. | Skies were overcast and occasionally broken with no precipitation and calm conditions. Air temperatures were in the 20s °F at upper elevations and near or above freezing at Canyon floor elevations. Previous windloading was evident and previous cornice development substantial on easterly aspects at mid and upper elevations. | • 5800 feet: 2/8 MF crust (crust) buried approximately 100 centimeters (cm), thickness approximately three cm (3 cm), and hardness was 1F. Crust strength: Strong= No integrity failure of crust with the weight of tester applied to hands pushing down on exposed and non-isolated portion of crust. Stability Test Results (Stability): ECTX x2. • 5500 feet: Crust buried approximately 80 cm, thickness approximately 10 cm, and hardness P+. Crust strength: Very Strong= No integrity failure of crust with the weight of tester applied while standing on/ jumping on exposed and non-isolated portion of crust. Stability: ECTX x2 • 5300 feet: Crust buried 70 cm, thickness approximately 4 cm, and harness K-. Crust strength: Somewhat strong but brittle when compromised= Integrity failure of crust occurred with the weight of tester applied to hands pushing down on exposed and non-isolated portion of crust. When crust failed it fractured locally on exposed portion of crust. Stability: ECTP24 x1. Conclusion of tests conducted on crust and crust interface at these location on 3/1/2018 is that the crust needs to be compromised for lower interface (beneath the crust) failure to occur. Greatest likelihood of crust compromise appears, based on results at these locations, to be at starting zone elevations near 5300 feet a.s.l. Crust interface condition(s) and strength were not tested at lower elevations (below 5300 feet). NOTE: All stability tests conducted after isolating entire ECT | • No recent slab avalanche activity or obvious signs of instability observed. • Very small loose snow sluffs and roller-balls observed in the afternoon |
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| 2018-02-28 | 05:30:00 | Burnout | Steiner | Toured up the looker’s right side of the Shed 4C “Burnout’ avalanche path to the Burnout starting zone. Conducted test profile at 5270 feet on a southeasterly aspect (1260). Descended same route. | Skies were overcast with intermittent light snow (S1) and gusty westerly winds. Windloading (crossloading) occurring on easterly aspects. Air temperatures were in the high teens and low 20s °F. | • HS 235 cm (0 cm at ground). Air temperature at site -7 C or 190 F • Upper 70 cm (from surface) consisted of F hardness precipitation particles and decomposing grains. • 70 to 75 cm from surface was the 2/8/18 P+ hardness melt-freeze crust... This crust was the main focus of this profile and remains well-established. • Interface snow grains above the crust consisted of F- mixed-form snow grains. However, bonding of this soft interface with the crust was “good” at this location. • More advanced faceted grains below the crust exhibited a 1F- hardness and were reactive in ECT stability test(s). ECTP23 x2 @ 155 cm (from ground). • HS 210 cm (0 cm at the ground). • Although ECTP results were conclusive and the ECT block slid quickly and clean into the pit, it obviously required a full isolation of the ECT column and compromised the 5 cm crust that is currently an integral part of the upper snowpack stability at this location. • It appears in order for massive failure to occur in the form of an avalanche on the layer of facets beneath the crust at this location, the crust would have to massively fail itself and exhibit a propensity to propagate as a snow layer. • Further observation regarding instability associated with this crust/ facet interface will be on-going. • The remainder of the column was not tested with ECT or other stability test methods but did consist of an additional four (4) decomposing crust layers and relatively weak snow interfaces (4F). • Again, more detailed observations/ stability tests regarding these deeper seated crusts and crustal interfaces will be conducted in the near future. | • No recent slab avalanche activity or obvious signs of instability observed. | |
| 2018-02-22 | 16:45:00 | Shed 11 | Clark | Left the rail grade at the Java East weather station and climbed the SW ridge of Running Rabbit Mountain to the Shed 11 weather station at 6400 feet. After some much needed maintenance work on the station we descended the same route. | Broken skies, no precipitation, and light to moderate winds from the east all day. Temperatures were in the single digits °F above 6000 feet elevation and mid to high-teens °F at the Canyon floor by the afternoon. | • Easterly winds were lightly loading westerly aspects above 5500 feet elevation (photo 1). Small test slopes on windloaded aspects were unreactive to ski cuts/stomps. • Also cut one small refrigerator-sized, or perhaps only dishwasher-sized cornice onto the wind loaded slope below with no results. • We only had to ski about 20-30 m below the SW ridge of Running Rabbit to get out of the wind slabs and into some nice powder skiing. • Large cornices still loom above the Infinity, Shed 9, and Shed 7 West avalanche paths. • It’s been a cold and dry week in JFS Canyon with only a trace of new snow at lower elevations since Monday (2/19). Low temperatures dipped down to -30 °F earlier in the week at the Canyon floor. | • No avalanche activity observed. | |
| 2018-02-15 | 19:00:00 | Shed 9 to Shed 5 | Clark | Toured up the south face of Snowslip Mountain via the Shed 9 Path and over the ridge at 7000 feet elevation to the Shed 7 weather station. After some maintenance work on the station we descended the Shed 5 path back to the rail grade. | Scattered clouds in the AM, then mostly cloudy by the afternoon with very light snowfall and light westerly winds. Air temperatures 10-15°F above 6000 feet elevation and low-20s °F at the Canyon floor. | • Since Tuesday the 13th, the Canyon floor picked up another 7 cm of snow and elevations above 6000 feet accumulated another 15-25 cm. • Recent wind slabs were slowly building, mostly on westerly aspects. These were small and thin wind (10-30 cm thick). • Test slopes produced some minor cracking and occasionally we could get a little tabletop-sized wind slab to release. • Large cornices are present in the Infinity, Shed 9, and Shed 7 W avalanche paths (photo 1). • Feb 8 crust was mostly supportable throughout the tour. • Dug a snowpit to the ground at 6600 feet in the Shed 9 path on south aspect, 35° slope, HS=270 cm. o Multiple ECTNs in the upper 70 cm of the snowpack but no propagating fractures. o The December facets were present at the base of the snowpack, see pit profile (photo 2). | • No avalanche activity observed. | |
| 2018-02-13 | 17:00:00 | Shed 11 SZ and Weather Station | Clark | Toured up the south face of Running Rabbit Mountain on the ridge separating the Shed 11 and Shed 10.7 avalanche paths. High point was at the Shed 11 weather station. After some maintenance on the station we descended the Shed 11 path back to the rail grade. | Broken skies, no precipitation, and light west-northwest winds all day. Air temperatures rose from just below 0°F in the morning to the mid-20s °F by the afternoon at the Canyon floor and into to the mid-teens °F above 6000 feet elevation. | • Found variable snow conditions on the tour. o The Feb 8 crust extended up to about 6000 feet. o On the Shed 11/10.7 ridge above 5000 feet elevation the recent east winds had raked the slopes down to the Feb 8 crust. o Westerly aspects had recent wind slabs on top of the Feb 8 crust and varied in depth from 10 cm to over 1 m thick. o Observed some minor cracking in these wind slabs (1-2 m) in length. • Dug our first snowpit at 5400 feet in the Shed 11 path on a wind-loaded SW aspect. o Recent wind slabs 50-75 cm thick rested on top of the Feb 8 crust. Multiple ECTNs within these wind slab layers. o Found another crust 80-100 cm beneath the surface. This crust was not reactive in the first Extended Column Test, but was in the second with ECTP24 on a thin layer of facets on top of the crust. • Dug a second snowpit in the Shed 11 path at 6200 feet on a SE aspect. o HS=158, 36° slope angle, pit profile attached (photo 1). o Two Extended Columns test resulted in multiple ECTNs in the upper 60 cm of the snowpack, but no propagating fractures. o The Feb 8 crust was buried 50 cm deep at this location. o The Thanksgiving crust was absent here but the early December facets were present at the bottom of the snowpack. | • Yesterday a recent wind slab was observed in Path 1163 with debris running 2/3rds path and terminated above the rail grade. • No other recent avalanche activity observed. |
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| 2018-02-05 | 17:00:00 | Burnout/ Shed 5 | Clark | Toured up the southeast ridge of Snowslip Mountain above the Burnout and Shed 5 avalanche paths to an elevation of about 6000 feet. Dug a snowpit there and descended the Shed 5 path back to the rail. | Skies were overcast and air temperatures were the low to mid-teens °F. Light snowfall for most of the day with light and variable winds | • New snow accumulations: 18 cm overnight and another 5 cm today in Essex. • Above 6000 feet elevation, we found approximately 50-70 cm of additional snow has accumulated since the middle of last week. • Last night we had a short period of rain. Subsequently we have a new rain crust from the Canyon floor to about 5500 feet elevation. This is buried under 10-20 cm of powder and skis nicely. • Dug our snowpit at 6000 feet in the uppermost starting zone of the Shed 5 path on an ESE aspect, 26° slope. HS = 275 cm o Performed an extended column test. Had a propagating fracture 55 cm down from the surface on a density change within the storm snow that came in over the weekend, ECTP 27. o Second ECT yielded no propagating fractures. o A deep tap test on a suspect looking layer sandwiched between some old windslab resulted in DT 17 Q1, 120 cm down from the surface. o The Thanksgiving crust and early December facets were present at the bottom of the snowpack. | • Saw one small wind slab had released on a steep cut bank just above the rail grade near the east end of the Jake’s avalanche path. This was cross-loaded from the recent winds we experienced at the Canyon Floor over the weekend (Photo 1). • No other avalanche activity observed. • No other obvious signs of instability during the tour. |
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| 2018-02-01 | 17:45:00 | Shed 7/ Snowslip | Clark | Returned to the Snowslip weather station for additional maintenance today. Toured up the Shed 7 west path and continued on the Snowslip Mountain ridge, over the prominent cornice feature, and onto the south summit of Snowslip to the weather station location. Descended the Shed 7 West path | Skies were overcast and air temperatures were in the mid-20s °F at the Canyon floor and mid-teens °F above 6000 feet throughout the day. Light snowfall for most of the day with occasional moderate snowfall rates. Moderate to strong west winds were actively loading easterly aspects at elevations above 6000 feet all day. | • New snow accumulation of 4-6 inches since yesterday. • Heavy windloading on easterly aspects above 6000 feet elevation. • Cornice growth has continued over the past 24 hours. Our route cut through the Shed 7 West cornice was completely filled back in today. • A large cornice has also formed at the top of the Infinity avalanche path. | • Saw one very small wind slab had released below the cornice in the Shed 7 West path. • Pieces of the Shed 7 West cornice have been breaking off and sending small chunks of debris down the path. Most of this debris makes it only about 500 feet downslope. • No other obvious signs of instability during the tour. |
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| 2018-01-31 | 00:13:30 | Shed 9 Upper Starting Zone | Steiner | Toured up the Shed 7 path to the Shed 7 West path and continued to the NE ridge of Snowslip Mountain. Continued on the Snowslip ridge, over the prominent cornice feature and onto the Snowslip weather station to troubleshoot current function issues. Then continued into to starting zone elevation of Shed 9 and conducted a full data profile. Descended the Shed 7 West path. | Skies were mostly overcast with occasional broken skies. Air temperature were below freezing at all elevations throughout the day. Very light snowfall for most of the day with occasional moderate snowfall rates. Winds were predominately westerly and active windloading was occurring on easterly aspects at elevations above 6000 feet. | • New snow accumulation consisting of broken precipitation particles and graupel. • Windloading on easterly aspects. • No obvious signs of instability on tour. • Cornice growth is substantial on mid-upper elevation (above 6000’) easterly/ northeasterly aspects. • Full profile at 6756’ on a southeasterly aspect 28 degree slope. (Profile Attached as a JPEG image). • HS 194 cm (0 cm at the ground). • Stability Test results: ECTN14@ 176 cm (from ground). CT24Q2 @ 132 (No repeat on ECT or CT results) • Thanksgiving crust and basal facets were present at this profile location. | • No obvious signs of instability on tour. • No recent avalanche activity observed. |
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| 2018-01-23 | 21:45:00 | Path 1183 Starting Zone | Steiner | Toured up the looker’s right ridge of the Cascadilla drainage to the upper most elevation (~5960 feet a.s.l.). From this point, we descended toward the northwest and along an unnamed sub-ridge that is adjacent to the starting zone of avalanche prone terrain that produced a size 3 avalanche on 2/6/2017. The resulting avalanche ran full path, destroyed FEC powerline infrastructure, and buried both mains of the BNSF Railway under six feet (6’) of debris at the Railway’s milepost 1182.9 (~ MP 1183). Hence the path’s identifier, Path 1183. The furthest terminus point of debris was on US Highway 2. The purpose of today’s observations in the starting zone of Path 1183 was to become orientated with the Path 1183 terrain and also conduct a full snow profile at the upper starting zone elevation of Path 1183. | Skies alternated between broken cloud cover to fully overcast with occasional very light snowfall (S-1). Winds were mostly calm with occasional light gusts from the west. Air temperatures were in the mid-20s °F at the upper starting zone elevations and near freezing on the Canyon floor. Altogether, very pleasant weather. | • Approximately 6 cm of graupel in the past 24 hours on top of decomposing precipitation particles.. • No wind-loading was occurring and no obvious signs of instability at the elevations encountered on the tour. • Full profile at 5600’ on an easterly aspect 36 degree slope. (Profile Attached as a JPEG image). • HS 210 cm (0 cm at the ground). • Stability Test results: ECTP30@ 40 cm at upper interface of December facets. ECTX (No repeat on ECTP results) DP15 Q3 @ 40 cm | • No recent avalanche activity observed. | |
| 2018-01-18 | 17:00:00 | Shed 11 SZ | Clark | Left the rail grade from the Java East weather station and climbed the SW ridge of Running Rabbit Mountain to the Shed 11 weather station at about 6400 feet. Dug full profile in the starting zone of the Shed 11 path. Descended the same route. | Light rainfall up to about 4500 feet elevation, received 0.45 inches of rainfall at the Canyon floor since 0600 this morning. Encountered a soggy wintry mix from 4500-5500 feet, then light snowfall above 5500. Above 6000 feet the snow was barely dry enough to be transported by the light to moderate NW winds. | • Dug on a SE facing, 30° slope at about 6400 feet in the Shed 11 avalanche path. Two separate extended column tests resulted in propagation on two different layers. The first test – ECTP18 about 50 cm down on top of the Jan 9th crust (2 cm thick at this location) and then ECTP20 about 110 cm down on top of the early December facets. Performed the second test – ECTP21 and ECTP 29 on the same two layers respectively (pit profile attached). • After the ECT, found a very thin layer of facets had formed on top of the Jan 9th crust. • Above 6000 feet there was about 10 cm of new snow by noon on top of our newest crust formed during the warm sunny weather earlier in the week. • NW winds were lightly loading southerly-easterly aspects above 6000 feet. Very small and thin windslabs were just beginning to form but these were unreactive to ski cuts. | • No recent avalanche activity observed. • Numerous wet loose avalanches (D1-D2) had ran on sunny aspects at all elevations during the clear weather/ high pressure period earlier this week. |
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| 2018-01-12 | 15:43:00 | Shed 7 West | Steiner | Toured up the Shed 6/7 ridge, across the top of the Shed 7 East SZ and continued on ridge to the upper starting zone of Shed 7 West. Conducted snow observations and stability tests in the upper starting zone of Shed 7 West. Descended the Shed 7 West path. | Overcast skies, light snow, moderate westerly winds with occasional easterly gusts, Air temperature ranged between the teens °F at Canyon floor elevations and 20s°F at our upper most elevation. | • No obvious signs of instability. • Surface snow consisted of unconsolidated precipitation particles on top of a well-established rain crust at elevations below 6000 feet elevation (a.s.l). • Above 6000 feet, evidence of the subsurface rain crust diminished and surface snow consisted of unconsolidated snow atop more robust subsurface snow layers. • Recent windslabs and wind loading on easterly aspects above 5400 feet elevation a.s.l. • Conducted full profile and stability tests at 6638 in the starting zone of Shed 7 West. Profile was full-depth and on a 32 degree southeasterly aspect. HS= 205. Stability test results: ECTN20@ 150 cm. DT24@20. Q3 • Refer to attached profile for further details. | • No recent avalanche activity observed. | |
| 2018-01-10 | 17:00:00 | Shed 7 East | Clark | Toured above Shed 7 on the south face of Snowslip Mountain along the Shed 7/6 ridge to 5800 feet. Dug a snowpit at our high point and descended the Shed 7 east path back to the highway. | Overcast skies with S1-S2 precipitation all afternoon. Air temperatures were in the single digits °F with steady moderate to strong easterly winds. As of 1500 ridgetop winds have clocked back to the west. | • Travel on skis was fast and efficient today with 17-30 cm of new snow on top of the new rain crust that formed overnight. • East-northeast winds were actively loading westerly-southerly aspects at all elevations. • We could trigger very small wind slabs on small test slopes (photo 1). Also noted some minor shooting cracks on recently windloaded terrain. • We dug one snowpit at 5800 feet on a slightly wind-loaded 30 degree slope with a south-southwest aspect. Total snow depth here was 113 cm. The rain crust formed last night had already been buried under 30 cm of new snow. Overall still finding a poor structure snowpack (photo 2, snowpit profile) but the only result in our Extended Column Test was ECTN5 @ 105 on a slight density change in the new storm snow. | • Very small wind slab avalanches released with some forceful ski cuts/stomps. • No naturals observed but visibility was very limited. • We confirmed that Shed 7 East ran during the late December avalanche cycle with debris terminating at the upper edge of the snowshed. |
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| 2018-01-02 | 23:30:00 | Shed 10.7/11 Starting Zones | Clark | Toured up the ridge that divides the Shed 11 and Shed 10.7 avalanche paths on the south face of Running Rabbit Mountain. Climbed to our weather station at about 6400 feet and also dug a snowpit in the upper starting zone of the Shed 11 path. Descended the same route. | Mostly clear skies with no precipitation and air temperatures ranging from single digits to high-teens °F at the Canyon floor and low-mid 20s °F above 6000 feet. Winds were mostly calm or light from west. | • We noted two audible collapses on our descent, one up at about 6200 feet in the starting zone of Shed 10.7 and another on the ridge around 5000 feet. But we did not see any shooting cracks or recent avalanche activity. • Found variable conditions on our tour, from deep unconsolidated powder to supportable windslabs. Also noted a thin, weak sun crust was forming on slopes exposed to full sun. • East winds have formed hard slabs on westerly aspects and along the Shed 11-10.7 ridge crest. • We dug one snowpit at 6400 feet on a 33 degree slope with a south aspect. Total snow depth here was 107 cm. Snow profile and an Extended Column Test revealed improving strength and little to no energy (ECTX). But we still found the early December faceted layer at the bottom of the pit (photo 1, snowpit profile). • Of note, the snowpit location was snow free after the Thanksgiving rain/warm up event. The bottom 10 cm here were the facets from the early December high pressure period. | • No recent avalanche activity observed. • We did see an old crown on the east face of Mount Cameahwait (photo 2) and noticed several large (D2-D3) debris piles down in the valley bottom of Sheep Creek from avalanches that ran on the southeasterly aspect of Snowshed Mountain. |
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| 2017-12-26 | 17:20:00 | Burnout to Shed 7 East | Clark | Toured up above Shields Creek on the southeast ridge of Snowslip Mountain to the Shed 7 East weather station at 6300 feet. Dug one snowpit just above the weather station on an east facing slope and conducted a full profile. Descended the same route. | Mostly clear skies with no precipitation and cold air temperatures ranging from 3 to 10 °F at elevations between 4000-6300 feet. Winds were light, blowing mostly from the west and occasionally loading easterly aspects above 6000 feet (photo 1). | • Overall the snowpack has settled and stabilized since last week. Unfortunately we’ve found a poor snowpack structure with the layer of faceted snow sitting beneath last week’s storm snow still a concern. • Depths on our snow stakes located on the Canyon floor have decreased by 20-25 cm over the past six days. • During our ski tour we did not observe any obvious signs of instability such as shooting cracks, collapsing, or recent avalanche activity. • Trail-breaking was much easier compared to a week ago with ski penetration only 25-40 cm. • Ski cuts on small test slopes did not produce any notable results. • We dug one snowpit at 6300 feet on a 23 degree slope with an easterly aspect. Total snow depth here was 145 cm. Snow profile and an Extended Column Test revealed improving strength and little to no energy (ECTX) but poor structure (photo 2, snowpit profile). • Of note, the Thanksgiving crust at our pit location was an impressive ice mass almost 40 cm thick. Above this was about 20 cm of facets from the early December high pressure period. | • No avalanche activity observed. | |
| 2017-12-20 | 18:05:00 | Burnout Starting Zone Elevation | Clark | Toured up above Shields Creek on the southeast ridge of Snowslip Mountain to an elevation of 5300 feet and to the top of an avalanche path called “Burnout.” Dug one snowpit here on a southeast facing slope and conducted a full profile. Descended the same route. Also drove multiple times through John F. Stevens Canyon and observed numerous slab avalanches that released in the past 24 hours (details below). | Mostly clear skies, calm winds, and air temperatures ranging from 12-18 °F at elevations between 4000-5300 feet. No precipitation. | • Storm totals from the previous 2 days ranged from 60-100 cm. Winds were light or even calm during the Dec 18/19 storm and the new snow had very low densities ranging from 5-8%. • Trail-breaking was slow and arduous with ski penetration sometimes nearing 100 cm. • The snowpack (below 5500 feet) before Dec.18th was less than 20 cm deep in most places and composed entirely of facets. The new storm snow on top of these facets has created unstable conditions which we observed throughout the day. • For the entire length of our tour the snowpack would collapse under the weight of our skis with audible whumpfing noises. Shooting cracks would run across the snow surface sometimes for several tens of meters (photo 1), through dense trees, and around terrain features like small sub-ridges. • We stuck to slopes less than 30 degrees on our tour and did not trigger any avalanches on slopes we travelled across nor on connected slopes that were steeper than 30 degrees. • We dug one snowpit at 5300 feet on a 25 degree slope with a southeast aspect. Total snow depth here was 110 cm. As suspected, the new storm snow would fail and propagate in an Extended Column test on top of the facets near the ground. ECTP 26 at 20 cm (0 cm is at the ground). | • We observed numerous avalanches that likely ran last night and yesterday on all aspects and elevations in the greater John F. Stevens Canyon area. Most of these were small to medium sized (D1-D2) slab avalanches that failed either on the basal facets or on some density change within the new storm snow. • Several avalanche paths that threaten BNSF Railway slid including: Shed 7 East, Shed 9, Infinity, Shed 10, 1163, and Shed 10.7. However associated debris terminated well above the rail grade typically running 1/3rd to 2/3rds path. • We also noted a larger (approaching D3) avalanche on the southeast face of Shields Mountain in Glacier Park (photo 2) as well as D2-sized crowns on the east face of the Devil’s Hump and the east face of Java Mountain on the Flathead Natl. Forest. |
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| 2017-03-22 | 05:00:00 | Shed 10.7 Starting Zone | Steiner | On 3/21 toured up the Shed 10.7/11 ridge to approximately 6400 feet elevation. Descended same route. | Clear skies with scattered clouds. Winds were calm with light gusts from the east. Morning air temperatures at all elevations were below freezing and warmed throughout the day to above freezing at all elevations by 1300. Canyon floor air temperatures climbed to above 100C (500 F) by 1500. | • Well established melt-freeze snowpack surface in the morning hours at all elevations. • No recent wind transport. • No recent avalanche activity observed (Since at least 3/18/17). • Excavated a snow pit and conducted ECT stability tests at approximately 6350 feet elevation on 32 degree, south facing aspect. Snowpack depth at this location was 120 centimeters in depth, wet, and isothermal at 00 C. Layering in this profile was difficult to distinguish as most of the snowpack consisted of clustered melt forms (2-2.5mm in size). Basal facets in the bottom 15 cm of the snowpack remained identifiable in faceted form- 2mm in size. • Conclusive ECTP results with moderate force (ECTP 13, 14) (X2) in a density change 40 cm from the snowpack surface. Perhaps related to an old crust weak layer interface but distinction was not possible as all snow grains in this portion of the snowpack had been exposed to melt/freeze conditions and snow grains were melt forms. Snow layer hardness within the area of propagation was 1F+ above the propagation and F below. • No other ECT results were observed in stability tests conducted at this location. • Based on conclusive ECTP results, this layer interface, although not easily identifiable at this location, is our greatest layer of concern- particularly when melt/freeze integrity in surface melt-freeze crust is compromised due to solar input and warming. | • No recent avalanche activity observed (Since at least 3/18/2017). • No active windloading observed. • Cornice development remains substantial on easterly and northeasterly aspects. |
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| 2017-03-13 | 16:15:00 | Burnout to Shed 7 | Clark | Began the tour at the Burnout avalanche path and the climbed the SE ridge of Snowslip Mountain above the Shed 4D, Shed 5, and Shed 7 East avalanche paths. Dug a snowpit near the Shed 7 weather station in the very upper reaches of the Shed 7 East path (6300 feet, ESE aspect, 25° slope. Climbed a little higher on the ridge to about 6500 feet elevation in order to better view the cornice fall in Shed 7 West. Descended the same route. | In the morning skies were broken with no precipitation and periods of sunshine. By early afternoon skies were overcast with very light snow above 5500 feet and very light rain below this elevation. Moderate to strong west-southwest winds at all elevations all day. Air temperatures in the high 30s to low 40s °F at the Canyon floor and just above freezing at elevations above 6000 feet. | • Snowpack on the tour was quite variable. Below 5500 feet encountered a spring-like snowpack with a thin, breakable melt-freeze crust over wet snow on the surface in the morning which turned into wet, mashed potato snow on the ski down in the afternoon. Above 5500 feet found a mix of wind slabs (sometimes supportable on skis) along with sticky powder on the sunny slopes, and cold, dry powder on shaded slopes. Skin wax was helpful. • While the winds were steady at moderate speeds with occasional strong gusts, by early afternoon the actual wind-loading had tapered off as the warm temperatures and sunshine began to melt and stiffen the surface snow. • Wind slabs encountered on the tour were very stubborn. No releases, collapses, or shooting cracks observed. • HS at the snow pit location was 260 cm (0 cm at the ground). The Feb. 10 crust was down 90 cm from the surface. A thin layer of facets was seated on top of the crust, CT 25 SP result in a compression test on this layer, but no fractures with an extended column test. Also observed fractures but no propagation in the upper 30 cm of the snowpack, some of which occurred just below the mid-Feb crust. • Snow was getting quite punchy by early afternoon below 5500 feet elevation. There is plenty of wet loose snow for entrainment at the mid to low elevations. | • A large chunk of the cornice in Shed 7 West broke out recently (photos attached). This triggered a very small wind slab immediately below the ridge crest. Associated debris ran only a few hundred feet. • A few small wet loose sluffs ran in Burnout and Shed 4D. • Otherwise no other new (overnight and today) avalanche activity observed by 1400 when I left the Program Area. |
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| 2017-03-08 | 05:00:00 | Shed 11 Starting Zone/ Ridge | Steiner | Toured up the Shed 10.7/11 ridge to approximately 6400 feet elevation. Dug a test pit and performed ECT stability tests at this elevation on a southerly aspect. Descended same route. | Overcast skies with intermittent light snowfall. Winds were moderate with stronger gusts from the west. Very active windloading on easterly aspects above 5000 feet elevation. Morning air temperatures at all elevations were below freezing when we started our tour and warmed throughout the day. Canyon floor air temperatures climbed above freezing by afternoon and upper starting zone elevations remained below freezing with highs reaching into the upper 20s F. | • An audible collapse was felt and heard on an easterly aspect snow pillow under the weight of two skiers. This occurred at around 6000 feet elevation. • All available snow for wind transport was being actively loaded onto east-facing leeward aspects above 5000 feet elevation (Photos Attached). • Cornice development on easterly aspects is substantial. • Excavated a snow pit and conducted ECT stability tests at approximately 6400 feet elevation on 30 degree, south facing aspect. This pit was dug to a depth just below the 2/9-10 rain crust (~120 cm). • Conclusive ECTP results with hard force (ECTP 28, 23, and 24) (X3) in approximately 5 cm of facets located onto of the February 9/10th crust. These failures were occurring approximately 80 cm (32”) from the snowpack surface. Based on conclusive ECT results, the facets located atop the February 9/10th crust are our greatest layer of concern at this location. | • No natural avalanche activity observed today. • Substantial cornice development. • Intentionally skier triggered a few relatively small and very small soft wind slabs on easterly aspects. |
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| 2017-03-01 | 12:30:00 | Burnout to Shed 7 | Clark | On 2/27 toured up the Burnout avalanche path west of Shields Creek to about 5300 feet. Conducted a full snow profile at that elevation on a SE aspect and then continued up the ridge, topping out at the Shed 7 weather station at 6300 feet. Returned via same route. | Overcast and broken skies with occasional very light snowfall. Southwesterly winds were light to moderate above 6000 feet and the low-density snow was actively transporting and loading easterly aspects. Air temperatures ranged from the mid-20s °F at the Canyon Floor to the low teens °F above 6000 feet. | • Some very minor shooting cracks in the new wind slabs forming on easterly aspects above 6000 feet. • Noticed recent wind slabs on westerly aspects from the previous day’s E-NE winds above 6000 feet. • Below 5000 feet temperatures have cooled enough for the Feb crusts to become supportable, making for fast traveling. • Pit profile at 5300 showed only 4 distinct layers. Top 20 cm was F-hardness powder sitting on top of a 20 cm thick melt freeze crust at P-hardness. The top 20 cm of powder snow was starting to facet. Beneath the crust and running down to the ground, there were two layers at, or near 1F-hardness composed of melt-freeze clusters. • Fractures occurred in the snowpit underneath the melt freeze crust after hard force but with no propagation. • Above 5000 feet in locations sheltered from the wind, approximately 20-50 cm of snow has accumulated on top of the Feb 10 crust. • Greatest concerns with the snowpack in the near future are the recent wind slabs. However these are relatively small and should not pose a threat to railway operations. Any debris associated with a wind slab avalanche initiating above 6000 feet will likely terminate well above the tracks. | • No recent avalanche activity observed. | |
| 2017-02-20 | 15:20:00 | Shed 10.7 & Shed 11 Starting Zones | Clark | Toured up the Shed 11/10.7 ridge to the weather station at 6400 feet and just above the top of the Shed 11 avalanche path. Dug one hasty pit in the very upper reaches of the Shed 11 start zone. Descended the same route. | Overcast skies, light winds from the south-southwest, and air temperatures in the high 20s-low-30s °F at elevations above 5000 feet. Intermittent periods of light to moderate snowfall above 5000 feet. Below this elevation temperatures were in the mid-30s °F and precipitation fell as a rain/snow mix. | • Snowpack encountered on the tour was variable. Below 5000 feet encountered a breakable crust with punchy, wet, isothermic snow underneath. Skis sometimes penetrated 50-100 cm to the ground. Very slow going and treacherous skiing. Above 5000 feet found supportable crust with about 2 cm of fresh snow on top. Travel was fast and skiing wasn’t bad. • No wind loading was observed on the Shed 10.7 ridge and immediate vicinity. Distant terrain was obscured and could not tell if wind-loading was occurring on terrain above 7000 feet. • No shooting cracks, audible failures, or other signs of unstable snow. No rollerballs or wet loose activity observed. • Hasty pit at 6400’ on a 30 degree slope, S aspect. 170 cm HS (0 cm at the ground). Extended column test yielded ECTN 13 at 140 cm. This fracture occurred under a 15 cm thick layer of large, moist, melt-freeze grains located immediately underneath the Feb 10 crust. The Jan 19 crust was about 80 cm below the surface, no fractures on this layer. Snowpack was moist throughout the column. | • No recent avalanche activity observed. | |
| 2017-01-31 | 07:30:00 | Shed 7 West Starting Zone | Clark | On 1/30 toured up the looker’s left side of the Shed 7 path to the Shed 7 West path. Continued up the Shed 7 West path on the looker’s left side and climbed to ridge that separates the Shed 8 starting zone (approximately 5800’ elevation) and the Shed 7 West starting zone. Continued to approximately 6300 feet elevation and conducted a full profile on a easterly aspect of Shed 7 West. | Overcast and broken skies with no precipitation. Westerly winds light to moderate with stronger moderate gusts. Snow transport onto easterly aspects occurring at ridgeline elevations. Air temperatures relatively warm at all elevations with above freezing air temperatures at Canyon floor elevations and in the upper 20s F at upper starting zone elevation(s). | • No audible failures, collapsing, or shooting cracks. • Active windloading occurring on easterly aspects. • Surface ~10 cm (4”) windslab forming on easterly aspects at upper starting zone elevation(s). • Below 5000 feet, a prevalent surface or near surface rain and/or melt-freeze crust (formed 1/18-1/19/17) remains as reported on 1/25/17. However, this crust has softened and is either not supportive or only semi-supportive under skier weight. • Above 5000 feet elevations approximately 5 cm (2”) to 10 cm (4” of new snow is seated on the crust. • Also, between ~5800 and ~6100 feet elevation, we toured on a predominately south-southeasterly aspect that consisted of very poor structure (faceted) snow for the entire snowpack depth beneath the mentioned crust. At this location, the crust was not supportive and under skier weight, skis were penetrating at least 60 cm (2 feet) into facets and pole plants penetrated snowpack to the ground. • Above 6000 feet, noted crust also remains present and supportive of skier weight. • Above 6000 feet, faceted snow beneath the 1/18-1/19/17 crust was observed as on 1/25/17 but facets are rounding and appear to have more strength than observed on 1/25/17. • A full profile was conducted at ~6330 feet elevation on a 32 degree slope with an easterly aspect. Snow depth at this location was 140 cm (~5’). • Our layer of main concern in at this profile location were related to surface snowpack structure consisting of newly formed thin windslab and previously mentioned rounding facets beneath the crust. • Basal depth hoar at this profile was approximately 50 cm in height (0-50cm in profile height) and varied in hardness. 0-30 cm= F hardness and 30-50 cm= 4F hardness. Snow profile mid-pack was relatively strong and consisted of very small grain, tightly packed, rounding facets/buried windslabs. No significant stability test results. Significant T gradient was noted in the surface layers of the snowpack and between the snowpack surface and air. | • No recent avalanche activity observed. • No debris from previous avalanches observed in the Shed 7 West path. |
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| 2017-01-26 | 07:30:00 | Shed 10.7/ Path 1163/ Shed 10 | Clark | On 1/25 toured up the ridge between Sheds 11 and 10.7 to Shed 11 weather station. Continued up to the south summit of Running Rabbit mountain at about 7400 feet. Descended back to the rail via the Shed 10 path. | Broken skies with occasional very light snowfall (S-1). Calm or sometimes light winds from the southwest. Temperatures in the mid-high teens °F. | • No audible failures, collapsing, or shooting cracks. • No recent windloading. Prior windloading was noted on both easterly and westerly aspects. • Only trace amounts of snow accumulation at all elevations since 1/23. • Below 6000 feet, a prevalent surface or near surface rain and/or melt-freeze crust was noted and was present and noted on easterly and southeasterly aspects. • Above 6000 feet, we toured on numerous aspects and noted crust was present on north through southwest aspects at elevations above 6000 feet. • On ascent and descent, noted crust was approximately 5 cm (2”) in thickness and usually supportable under skiers weight to about 6000 feet. • Above 6000 feet, noted crust decreased in both thickness and hardness. • On occasion, above 6000 feet elevation and under the weight of skis/ skier, crust would break out (crack) as a relatively small plate. • Faceted snow beneath the crust was observed above 6000 feet elevation when skis penetrated the crust and/or a plate of crust broke out. • A full profile was conducted at ~6740 feet elevation on a 38 degree slopw with a south/ southwesterly aspect. Snow depth at this location was 143 cm (5’). • Our layer of main concern in at this profile location was a newly formed crust (1/18-19/2017) on top of 3 cm (1”) of facets. This crust/facet combination was buried only 3 cm from the snowpack surface. Although not a dangerous layer at this time, this crust/facet combination has the potential to be a problematic layer combination if (and when) future snowfall and windslabs are established upon it. • Basal depth hoar at this profile location appears to be rounding and hardness associated with this basal layer was the greatest we have observed in our profiles this season (4F). No significant stability test results. Significant T gradient was noted in the upper 10 cm (4”) of the snowpack and between the snowpack surface and air. | • No recent avalanche activity observed. • No debris from previous avalanches observed in the Shed 10 path. |
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| 2017-01-24 | 10:30:00 | Burnout/ Shed 5 Starting Zone | Clark | On 1/23 toured on the ridge above avalanche paths known as Burnout, Shed 4D, and Shed 5. Dug a hasty pit in the upper starting zone of Burnout. Then continued up to about 6000 feet and completed a full profile on the ridge just north of the upper starting zone of Shed 5. Descended the same route. | Skies alternated between broken cloud cover to fully overcast with occasional very light snowfall (S-1). Light winds from the E or NE or sometimes calm. Temperatures in the low-mid 20s °F. Pleasant weather. | • Only a trace to about 1 inch of new snow since 1/19. • Crust was supportable on skis until about 5000 feet then became breakable. Near 6000 feet the crust was getting to be pretty thin and one could zipper through on skis without too much trouble. • No wind-loading was occurring at the elevations encountered on the tour. And no wind-loading was observed at elevations above 6000 feet. • Hasty pit at 5100’ on a 24 degree slope, SE aspect. 75 cm HS (0 cm at the ground). About 2 cm new snow on top of crust. CT 23 @ 67 cm Q3 on a layer of facets just under the crusts formed during last week’s warm-up. Extended Column Test result was ECTX. Depth hoar and other faceted grains in the snowpack were beginning to round. • Full profile completed at 6000’ on a 28 degree slope, E aspect (profile attached). HS was 128 cm with about 3 cm of new snow on top of the crust from last week. At this location this crust was a single, thin (~1 cm) layer, P- hardness. Multiple layers of faceted grains within the snowpack and the depth hoar at the base were beginning to round. CT 14 Q2 @ 114cm on a layer of rounding facets and CT 24 Q2 @ 97cm on another layer of rounding facets. ECTN 24 and ECTN 26 on these same layers respectively. | • No recent avalanche activity observed. | |
| 2017-01-09 | 21:00:00 | Burnout and Shed 5 Starting Zones | Clark | Toured up the trimline of the Burnout avalanche path to the east ridgeline of Snowslip Mountain. Conducted a full profile and stability tests at just to the right of the Shed 5 starting zone. Descended same route. | • Overcast skies, light to moderate snowfall with intermittent heavy snowfall episodes. Approximately 4” of new snowfall occurred through the day. • Air temperatures fluctuated significantly Depending on location during the morning hours. • As an example, air temperature at Devil Creek, on the Canyon floor, was 80 F. At Essex, where we had just left, the air temperature was 210 F. Later in the afternoon the Devil Creek air temperature had impressively increased to 300 F. • Also, important to note, when we began our field observations in the morning, overrunning was occurring in the Program Area with warm air streaming over the previously entrenched cold air. • This overrunning condition was responsible, impressive snowfall rates and for significantly warmer air temperatures at Program Area upper elevations than what existed at lower elevations during the same time period. • Winds were westerly and light to moderate in strength. • Wind strength increased throughout the day. • Active windloading was occurring on easterly aspects during the afternoon hours at all elevations. | • In the past 24 hours, approximately seven inches (7”) of relatively dense (120 Kg/m3) new snow accumulation had been deposited on lighter density old snow interface. • This condition created an “upside-down” snowpack where the more recently deposited snow with greater density was fracturing and nearly sliding on the underlying lower density snow. • Newly deposited snow observed was very soft (fist hardness) and lacked structure for slab formation. • Only very localized propagation in newly deposited snow was observed throughout the day. • Older snow layers beneath newly deposited snow continue to be completely faceted and unconsolidated at elevations below 5200 feet. • Above 5200 feet, pockets of totally unconsolidated, faceted snow exist but there is also areas that have had significant windloading. • Substantial cornice development has occurred on easterly aspects above 5,600 feet elevation. • Full profile at 6000 feet elevation. 280 slope with SE aspect. Impressive windloading at this location. Snowpack depth was 205 cm. Structure consist of increasingly hard layers positioned atop 50 cm of 4Fand F+ hardness facets. Significant T gradient in a majority of the snowpack at this location. • No ECTP results in stability tests. CT2 and CT5 (Q3) observed in upper 30 cm of profile. CT17 Q3 observed 42 cm from snowpack surface at this location. | • No avalanche activity observed. | |
| 2017-01-07 | 09:00:00 | Shed 10.7/11 Starting Zones | Clark | On 1/6 toured up the Shed 11/10.7 ridge to the weather station just above the top of the Shed 11 avalanche path. Spent some time maintaining weather station and then dug a hasty pit in the very upper reaches of the Shed 11 start zone. Descended the same route. | Broken skies, calm or light and variable winds, and air temperatures in the single digits °F at elevations above 6000 feet. No precipitation. | • Snowpack encountered on the tour was variable. Below 5000 feet encountered shallow, faceted and punchy snow. Above 5000 feet found a mix of supportable, hard, wind slabs and a more recent wind crust that was breakable. Terrain was wind loaded on both sides the ridge. • Minor shooting cracks (1 m out from under skis) noted in the most recent wind crusts in a few isolated locations between 5000 and 6400 feet. • Hasty pit at 6400’ on a 32 degree slope, S aspect. 105 cm HS (0 cm at the ground), CT 18 @ 70 cm Q2 on a layer of small facets sandwiched between two wind slabs. ECTN 19 on this same layer. • Depth hoar at the bottom 5-10 cm of snowpack. No results in stability tests on this layer. Noted grains appeared larger/more developed than last site visit on 12/22. | • No avalanche activity observed. | |
| 2016-12-30 | 19:00:00 | Shed 7 East Starting Zone | Clark | On 12/29 toured up the ridge immediately to the east of the Shed 7 East avalanche path to the Shed 7 weather station. Worked on weather station and dug a pit on a NNE aspect at about 6400 feet. Descended via Shed 5 path. | Overcast skies, fairly steady moderate southwest winds, and air temperatures in the upper teens °F at elevations above 6000 feet and upper 20s °F at the Canyon floor. Snowed most of the day at a light to moderate rate (S1-S2) until about 1500 hours. | • 7-8 cm of very low density (4%) snow since 12/28 at our low elevation study plots (Java East and Devil Creek). • Unconsolidated snowpack below 5200 feet elevation. • West/Southwest winds were actively loading East/Northeast aspects all day above 5200 feet. • No audible collapses or shooting cracks. Full profile conducted on @ 6397 feet elevation and on a NNE aspect. Total snow depth= 150 cm 150-132 cm pp F 132-100 mixed 4F 100-90 Sm r 4F+ ECTP X1 @ 100 90-60 Sm r 1F- 60-30 f 4F+ 30-0 f F+ Significant T gradient observed in the upper 10 cm of snow profile. | • No avalanche activity observed. | |
| 2016-12-26 | 19:00:00 | Shed 7 East Starting Zone | Clark | Toured up the ridge immediately to the east of the Shed 7 East avalanche path to the Shed 7 weather station. Spent close to 3 hours working on the station. Descended via Shed 5 path. | Overcast skies, fairly steady moderate west to southwest winds, and air temperatures in the lower teens °F at elevations above 6000 feet and low 20s °F at the Canyon floor. Very light to light snowfall (S-1 to S1) throughout the day. | • 5 cm of new snow (at 8-10% density) since 12/22 at our low elevation study plots (Java East and Devil Creek). • West/Southwest winds were actively loading East/Northeast aspects all day above 5000 feet. • Also noted the “new” (since 12/20) wind-loading on westerly aspects from the easterly winds that occurred over the past week on the Shed 7/6 ridge. • Above 5500 feet, observed shooting cracks that would run 1-3 m out past our skis on the recently (within the past 24 hours) wind-loaded pockets • No audible collapses. | • Triggered a tiny (tabletop size wide, 20 cm thick) wind slab on a test slope at about 5500 on east aspect on Shed 7/6 ridge. • Triggered another tiny storm slab on a test slope at about 5500 feet on south aspect in the Shed 5 path. • Otherwise no avalanche activity observed. |
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| 2016-12-22 | 18:20:00 | Shed 10.7/11 Starting Zones | Clark | Toured up the Shed 11/10.7 ridge to the weather station just above the top of the Shed 11 avalanche path. Spent some time maintaining weather station and then dug a hasty pit in the very upper reaches of the Shed 11 start zone. Descended the same route. | Broken skies, calm or light southwest winds, and air temperatures in the upper 20s F at elevations above 6000 feet. No precipitation. A pleasant day to work on the weather station | • Snowpack encountered on the tour was quite variable. Still very punchy with no supportable base below 5500 feet. Otherwise found a mix of supportable wind slabs and then a thin wind crust which was not supportable. And then sometimes deep (1+ m) unconsolidated powder. Arduous skinning and sporty skiing. • Had one audible collapse on windslab pocket at about 5200 feet. • Hasty pit at 6400’ on a 32 degree slope, S aspect. 85 cm HS. Upper 35 cm basically a stack of wind slabs, 4F to 1F hardness. Bottom 50 cm was a layer of facets (4F-) to the ground. ECTP 26 on top of this layer. | • While skiing down the Shed 10.7/11 ridge noticed several cracks where some wind slabs just started to move downslope off the ridge crest, but then arrested in place. Likely occurred sometime on Tue or Wed. This was on skier’s left, and the western flank of Shed 10.7 path. Some of these cracks were up to 10 cm wide and close to 1 m deep (photos). • Otherwise no recent avalanches observed. But I suspect avalanches did occur, only the crowns were quickly hidden by the steady supply of wind-transported snow earlier in the week. |
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| 2016-12-21 | 06:15:00 | Shed 7 | Steiner | On 12/20 toured up the Shed 7/6 ridge to the Shed 7 weather station and then continued onto the eastern most ridgeline of Shed 7 West.. Conducted profiles just below the ridgeline proper on both a southwest exposure, looking into Shed 7 West and also on a northeasterly exposure of Shields Creek, | Overcast skies, moderate south-southwest winds with strong gusts, and air temperatures in the upper 20s F at all elevations. Intermittent snowfall throughout the day with light snowfall accumulations. | • Wind transport of available snow was substantial. Available snow was being constantly transported from westerly exposure terrain to southeasterly, easterly, and northeasterly aspects. • Substantial cornice development on ridgelines with easterly aspects. Due to consistent moderate winds and strong gusts, both profiles conducted were focused on identifying the observing the overall early season snowpack structure, identifying weak layers through observation, and conducting snowpack stability tests to confirm the existence of weak layers. All these snowpack observations were conducted without specific snow grain identification. Also, no specific snowpack temperature data was collected. • At approximately 1330, our first profile was conducted on 33 degree slope with a southwest exposure at 6500 feet in elevation. Snowpack at this location was 110 cm in depth and consisted mainly of 4F+ or 1F layering throughout its entire depth. No obvious weak layers were identified at this location and no propagation occurred during our one (1) ECT stability test. It must be emphasized that this profile location was getting pummeled by moderate and strong southwesterly winds while we were there. Our time exposed at this location was relatively short and this was the only test profile we observed on this southwest exposure. Just after 1400, we conducted our second test profile also at approximately 6500 feet elevation on a northeast exposure. This was conducted on a 32 degree slope and had a 160 cm snowpack. In this profile, basal facets were observed in the bottom 30 cm of the snowpack and no obvious weak layers were visually observed. Again, we conducted only one stability test, an ECT, and observed no propagation throughout the ECT column. We did have an ECTN result at 60 cm from the snowpack surface on buried layer that was visually obvious in the profile side wall. Hardness above this layer was 1F and below was 4F-. | • On descent from the Shed 7 West ridge we triggered two small soft slab avalanches from safe terrain on the ridge that separates the Shed 7 East starting zone and the Shed 5 starting zone. Both of these avalanches were triggered on southeasterly aspects and were soft slabs formed by recent windloading. • The largest of these two skier triggered avalanches had a crown that appeared to be greater than 50 meters (150’) in length and a crown depth that varied from 15 cm to 30 cm (0.5’ to 1’) in depth • Very difficult to view the results of these avalanches due to blowing snow. Also, no photos taken due to reduced visibility • One relatively small soft slab natural avalanche was also observed on an east facing aspect at approximately 5500 feet elevation in the starting zone of Shed 5 or what we refer to as “Test Slope 3.” Debris associated with this avalanche terminated in the starting zone. • Other signs of obvious instability were also noted on descent which included shooting cracks and snowpack collapsing |
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| 2016-02-23 | 21:00:00 | Shed 7 East/ Shed 5 | Steiner | Toured up the Shed 7/6 ridge to the starting zone of Shed 7 East. Conducted a full snow profile at this location and associated stability tests. Descended to the Shed 5 starting zone and conducted a test pit. Descended Shed 5 to the Canyon floor. | Broken skies, moderate westerly winds, and air temperatures in the 20s F at elevations above 5,200 feet (’) and 30s at lower elevations. No precipitation and wind transport of snow occurring onto S, SE, E, and NE aspects. | • Snow surface consisted of dry powder conditions to approximately 5000’ elevation (shaded aspect) and supportable melt/freeze conditions below that elevation. • No audible whoomphs, collapsing, or shooting cracks. • Full profile conducted at 6440’ on a 35 degree SE aspect. 200 cm HS. Profile consisted of dry snow in the upper 70 cm and moist snow below 130 cm to the ground. All layers in profile were 1F hardness or more. Recent windslab development was present in the upper 26 cm of snowpack. • Stability tests in Shed 7 East consisted of both ECT and CT. ECTN 24 and CTM 19 Q2 @ 174. This was our greatest layer of concern and existed between the interface of recent windslab development and underlying snow. • Test profile in Shed 5 was also conducted on a SE aspect. Snowpack depth was 110 cm and slope angle was 36 degrees. No significant results. • No temperature profile conducted. | • No recent slab avalanche activity observed. • Intentionally triggered a very small and isolated wind slab while approaching our profile location in Shed 7 East. This very small slab was 10-15 cm in depth and five (5) meters in width. It released on a steep convex roll and terminated with about three (3) meters vertical fall at the base of the roll. • No other slab avalanche activity observed. |
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| 2016-02-11 | 21:00:00 | Shed 11 | Steiner | Toured up the Shed 11/10.7 ridge to an area just above the Shed 11 starting zone. Conducted a snow profile at this location and associated stability tests. Descended the Shed 11/10.7 ridge back to the Canyon floor. | Broken skies, calm to very light westerly winds, and very warm air temperatures (40 F) at all elevations. No precipitation. | • No wind transport. Snowpack below 5,500 isothermal, wet grains, and unconsolidated to ground. • One audible “whoomph” at approximately 6,300 feet elevation on a ~32 degree slope with SE aspect. • Recent cornice fall and associated slab avalanche observed on a northeasterly aspect of Cameahwait. • Conducted a full profile on a 32 degree, S aspect (1870) at approximately 6420 feet elevation. • HS at profile location was 110 cm. Snowpack was moist throughout. Main focus of profile observations at this location was an interface located 40 cm from the snowpack surface. Interface consisted of a 4F hardness layer resting on a well-established 3 cm melt-freeze crust (1F+). Below the MF crust was a 42 cm layer with 1F hardness. • Stability tests on the layer interface of concern resulted in ECTX and a CT23 Q2. • No temperature profile conducted and no snow grains identified. | • Recent slab avalanche activity observed on northerly aspect of Mount Cameahwait- outside the Program Area (photo attached). This avalanche appeared to be a soft slab and to have been triggered by cornice fall. It released at an approximate elevation of 7400 feet and debris appeared to have terminated at approximately 7000 feet elevation. • No other slab avalanche activity observed. |
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| 2016-02-02 | 19:00:00 | Path 1163 | Steiner | Toured up the Shed 11/10.7 ridge to the southwest ridgeline of Running Rabbit mountain. Continued on SW ridge to the looker’s left side of the upper elevation starting zone of Path 1163 at approximately 7,400 feet elevation. Descended from this point approximately 150 vertical feet to our snow profile location. Once snow profile observations were completed, we descended back down the Running Rabbit ridge and the Shed 11/10.7 ridge. | Overcast, obscured, and broken skies, calm to very light westerly winds, and light snow showers throughout the day. Air temperatures averaged in the teens at upper elevations and mid-twenties at lower elevations. Observed no wind transport of available snow. | • Previous windloading on south, southeasterly, and easterly aspects. • No audible collapses and no remote triggers. • No cornice fall or avalanche activity observed. • Conducted a full profile on a 37 degree, SE aspect (1300) at approximately 7,250 feet elevation. • HS at profile location was 180 cm. Main focus of profile observations at this location was an interface located 101 cm from the snowpack surface. Interface consisted of 21 cm of mixed form snow grains resting on a well-established melt-freeze crust (1F+). Below the MF crust were 44 cm of mixed form snow grains ranging in hardness from F+ (below the MF crust) to 1F. Stability tests on this layer interface resulted in ECN X 2. No other layers propagated in this profile location. • No significant temperature gradient noted in this profile location. | • No avalanche activity observed. | |
| 2016-02-01 | 22:00:00 | Shed 10.7/11 | Steiner | Toured up the Shed 11/10.7 ridge to the starting zone elevation of Shed 11. Conducted maintenance work on the Shed 11 weather station. Excavated a full profile in a test slope near the SZ of Shed 11. | Partly sunny skies, calm to very light westerly winds, and light snow showers throughout the day. Air temperatures were in the teens in the morning and upper twenties by afternoon. No wind transport of available snow. | • Previous windloading on south, southeasterly, and easterly aspects. • Shallow and very soft windslab development on south and southeast aspects above 5,200 feet elevation. • Isolated and relative small area shooting cracks initiated under single skier weight. • No audible collapses and no remote triggers. • No cornice fall or avalanche activity observed. • Conducted a full profile on a 33 degree, S-SW aspect at approximately 6,500 feet. • HS at profile location was 138 cm. Main focus of snow profile data at this location was an interface located 74 cm from the snowpack surface. Interface consisted of small decomposing facets resting on a well-established melt-freeze crust. Stability tests on this layer interface resulted in ECTP17, 21, and 24. Both the ECTP 21 and 24 column slid off the MF crust and into the pit. All shear qualities were Q1- • No temperature profile was observed today. | • No avalanche activity observed. | |
| 2016-01-26 | 17:00:00 | Shed 10.7/11 | Steiner | Toured up the Shed 11/10.7 ridge to the starting zone elevation of Shed 11. Excavated a full profile in a test slope near the SZ of Shed 11 and also conducted an ECT stability test near the flank of the Shed 10.7 feeder path. Skiing conditions were good on ascent and descent at low elevations (below 5,200 feet) due good snow cover. Upper elevations were more difficult to travel due to deep windslab formation. | Overcast and broken skies, moderate westerly winds, and no precipitation throughout the day. Air temperatures were in low thirties at Canyon floor elevations and in the mid to upper twenties at elevations above 5,200 feet. Active windloading occurring on easterly aspects throughout the day. | • Windloading/ crossloading occurring on easterly and northeasterly aspects. • Deep windslab development on SE and E aspects above 5,500 feet elevation. • Isolated shooting cracks initiated under single skier weight. • One audible collapse noted at 6200’ elevation on a SE aspect and just above a convex roll. • No cornice or avalanche activity observed. • Conducted a full profile on a 33 degree, S-SE aspect at approximately 6,330 feet. • HS at profile location was 115 cm. Main focus of snow profile data at this location was an interface located 50 cm from the snowpack surface. Interface consisted of small facets and decomposing surface hoar resting on a well-established melt-freeze crust. Stability tests on this layer interface resulted in ECTP15 and ECTP16 Q1- failures. • No significant temperature gradient in the snowpack at the Shed 11 test slope location. 0 degree C snowpack T from 60 cm to the ground. • Also conducted an ECT stability test on the flank of the Shed 10.7 feeder path. This location was on a SE aspect at 6200 feet elevation and 32 degree slope. Snowpack depth was 133 cm and an ECT stability test resulted in propagation on the same layer interface of concern in the Shed 11 test slope. ECTP13 Q1- | • No avalanche activity observed. | |
| 2016-01-19 | 21:00:00 | Shed 7 East | Steiner | Toured up the looker’s right side of the Shed 7 path and then ascended onto the Shed 7 East/ Shed 6 ridge. Ski cuts in Test Slope 1 and then onto the Shed 7 weather station for a welfare check. Conducted a full profile just uphill from the weather station on a protected northeast aspect slope. Skiing conditions were good on ascent and descent due to fresh snow and a supportable crust buried beneath newly deposited snow. | Overcast and broken skies, moderate westerly winds, and no precipitation throughout the day. Air temperatures were in low thirties at Canyon floor elevations and in the mid to upper twenties at elevations above 5,200 feet. Active windloading occurring on easterly and northeasterly aspects throughout the day. | • Windloading/ crossloading occurring on easterly and northeasterly aspects. • Windslab conditions on S, SE, E, and NE aspects. • Shooting cracks and very small, isolated, soft slabs triggered under single skier weight. Triggering was intentional and prominent on lee aspects of various terrain features. • No audible collapsing or remote triggering of avalanches. • No cornice failures observed. • Conducted a full profile on a 29 degree, northeast aspect at approximately 6,400 feet. • HS at profile location was 141 cm. Snowpack at this location lacked any significant weak layers except for the bottom 16 cm of depth hoar. Stability tests resulted in an ECT-X and a CT20 Q2 at @91 cm. | • No avalanche activity observed today. As mentioned previously, we did intentionally trigger a very small isolated soft slab in Test Slope 1 (Southeast aspect @ 5200 feet (1576m)) that varied between 30 cm and 15 cm in crown height. This slab terminated immediately after being triggered. | |
| 2016-01-14 | 17:30:00 | Shed 6/7 Ridge | Steiner | Toured up the looker’s right side of the Shed 7 path and then ascended onto the Shed 7 East/ Shed 6 ridge. Conducted belayed ski cuts in Test Slope 1, 2 and 3. Also, collected data from a crown profile in Test Slope 2. Skiing conditions were poor on ascent and descent due to surface crusts, unconsolidated moist snow, and dense wind pillows. | Overcast skies, moderate to strong westerly winds, and light to moderate snowfall throughout the day. Air temperatures were in upper twenties (F) at all elevations. Wind loading occurring on easterly and northeasterly aspects. | • Windloading occurring on easterly and northeasterly aspects. • Shooting cracks under single skier weight in snow pillows on leeward aspects. • No audible collapsing or remote triggering of avalanches. • Conducted two (2) compression tests (CT) in Test Slope 2. These were conducted as part of a profile dug into the crown of an avalanche (crown profile) that was intentionally triggered by us. • CT results were CT19 Q2 @ 90 cm from the snowpack surface in the Test Slope 2 crown profile. Both CT tests failed on the weak layer interface of the previously intentional triggered avalanche. • The weak layer interface of both the CT and intentionally triggered avalanche consisted of a very thin 2-3 mm surface hoar (sh) positioned atop a pencil minus (P-) bed surface. • Evaluation of the snowpack was not conducted at deeper snowpack depths than the bed surface/ weak layer interface of crown profile. However, total snowpack depth at the Test Slope 2 location was 230 cm and snowpack surface temperature was -3.30 C. | • Evidence of relatively small natural slab avalanche activity observed in Test Slopes 1 and 3. Also saw recent debris in the northeasterly aspect of the Shed 5 starting zone. Associated debris terminated in upper 1/3 of path. Character of natural slab activity not known due to new snow and recent wind deposits. • Also, as previously referenced, we did intentionally trigger a relatively small slab avalanche in the starting zone of Test Slope 2 at approximately 1696 m (5600 feet) elevation. This avalanche is classified as (SS-ASi-R2-D1.5-I) and was approximately 30 meters (m) in width. Crown height measured 130 cm at its maximum thickness and 30 cm at its minimum thickness. Hardness varied between F and 1F-. The avalanche traveled approximately 130 lineal m to the max runout of the test slope and dropped approximately 90 m in vertical height. |
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| 2015-12-31 | 17:00:00 | Shed 7 West | Steiner | Toured up the looker’s left ridge of the Shed 7 West path. Dug a test profile at 6143 on an easterly aspect and then continued up the Shed 7 West path while traversing the path to a southerly aspect. Worked our way up the southerly aspect terrain to 6590 feet in elevation. At this location on a southeasterly aspect we conducted a full data profile. After completing profile observations we traversed further to the east along the Shed 7 ridge and followed the ridge to the starting zone of Shed 7 East. At this point, we dropped down to the Shed 7 weather station for a welfare check. All good. For descent to the Canyon floor we skied the skier’s left of the Shed 5 path. Skiing conditions were very good on ascent and good on descent. | Broken skies, light to moderate westerly winds, and no precipitation throughout the day. Air temperatures were in the teens throughout the day at all elevations. Wind loading occurring on easterly and northeasterly aspects. | • No audible failures, collapsing, or shooting cracks during today’s field observations. • Snow depth at test profile location, which was on an easterly aspect at 6,143 feet (1873 m) was 90 cm. No propagation in 3x ECTs. • However, we did have the entire ECT column collapse (2x) in basal depth hoar with moderate force applied. ECT columns collapsed on an ECT20 and .ECT18. • Full data profile conducted at 6590 feet (2009 m) Snowpack height at this location was 117 Slope angle was34 degrees with a southeasterly aspect. • ECT test in full data profile resulted in no propagation. CT test resulted in a CTH Q2 at a depth of 112 cm from the snowpack surface on a mixed form interface. • Basal depth hoar in full data profile appears to be rounding and average size was 1.5mm • Significant temperature gradient in full data profile between 20 cm and 100 cm from the ground surface. | No recent avalanche activity observed. However, later in the day isolated (very small) surface wind slab was forming on easterly and northeasterly aspects and triggering was easy. | |
| 2015-12-29 | 16:00:00 | Shed 4/5 | Steiner | Toured up to the Shed 4 weather station and cleared station sensors of recently accumulated snow. Clearing snow allowed all sensors to once again function normally and report accurate data. After clearing the weather station, continued up the Shed 4 ridge to 6000 feet in proximity to the Shed 5 starting zone. At this location we conducted a full data profile on a 38 degree southeast exposure. Once completed with collecting profile data, we skied back down to the Shed 4 weather station by traversing and dropping down the Shed 4 ridge. Skiing conditions were excellent on both ascent and descent. | Obscured skies, calm winds, and light snow throughout the day. Air temperatures in the teens throughout the day at all elevations. Trace amounts new snow during the day. | • Impressive snowpack settlement since 12/24 at all Canyon floor weather stations- between 10 and 17 cm. *However, some snow may have been lost on the HS stake with the 12/4-25 east winds. • No audible failures, collapsing, or shooting cracks during today’s field observations • Profile height= 117 cm. • Snow is currently well bonded on the upper interface of the 16 cm thick December 9th, knife hard, sandwiched ice mass. • Below ice mass, fist hardness 3 mm depth hoar. • ECT test resulted in no propagation. CT test resulted in moderate Q2+ failures at several profile layers-Not worthy of detailed discussion. • Significant temperature gradient in upper 67 cm of profile. | No avalanche activity observed. | |
| 2015-12-21 | 18:00:00 | Shed 6/7 Ridge | Steiner | Toured up the Shed 6/7 ridge to the Shed 7 Weather Station. Conducted maintenance on the Shed 7 weather station mast. All okay for now. Ascent and descent was of moderate difficulty due to early season snowpack conditions that consisted of shallow and unconsolidated snow. However, we were able to ski from ridgeline elevation to the Canyon floor. Very conservative skiing required below 5200’ elevation. | Broken and cloudy skies, light snow in the afternoon, and sporadic light west winds. Air temperatures in low to mid-twenties throughout the day. Only trace amounts new snow during the day. No windloading during the day however, previous windloading on southerly through easterly aspects was evident. | • Conducted ski cuts and belayed stability tests in Test slopes 1, and 3. No Results • No formal snow profiles conducted today. • No audible failures, collapsing, or shooting cracks during tour. | Observed recent natural slab avalanche in the starting zone of Shed 7 West at approximately 1100. Aspect was easterly and activity consisted of two separate slab releases; D1 and D2 in size. SZ elevation was between ~6800 and ~6600 feet. Debris appeared to consist of soft and harder slab material in both releases. Both avalanches appear to have been triggered by cornice fall and terminated in the upper 1/3 of path. Photos attached. | |
| 2015-12-04 | 20:30:00 | Shed 11 | Steiner | Toured up the Shed 10.7/11 ridge to the Shed 11 Weather Station. Main goal was to get the Shed 11 Weather Station back online… Success! Ascent and descent was difficult due to faceted snow conditions, intermittent ice crust, and shallow snowpack. Very difficult to set a skin line over 20 degrees due to upper snowpack facets… Would just slide backwards. Forced to walk down lower 1/3 of ridge due to shallow snowpack. | Cloudy skies, light snow, and light west winds. Air temperatures at all elevations in the teens. Only trace amounts of low density new snow during the day. No occurring or recent snow transport observed. | • No snow profiles were conducted. • Main layers consist of basal facets, a thick mid-pack crust, and facets in the shallow upper snowpack. • Isolated audible collapsing above 6,000 feet elevation. Collapsing seemed to be initiating below mid-snowpack crust. • Snow depth averaged 5” to 10” below 6,000 feet elevation and 10” to 20” above 6,000 feet elevation. | No avalanche activity observed. | |
| 2015-02-03 | 21:00:00 | Shed 5 SZ | Steiner | Toured up the Shed 7 path to the Shed 7 East path before exiting looker’s right onto the ridge above the starting zone of Shed 5 (6150 feet elevation). We then descended this ridge into the looker’s right side of the Shed 5 starting zone at an elevation of approximately 6000 feet. At this location we conducted a full profile. Once completed, we descended the looker’s right ridge of the Shed 5 path to the Canyon floor. Between the Canyon floor and our high point, approximately two (2) to eight (8) inches of new snow and wind transported snow was present on top of a well-established melt freeze crust that had formed during last week’s warm weather. Travel at lower elevations was difficult due to a thin snowpack and brush. However, snow conditions were excellent for skinning and travel at elevations above 5,200 feet was good. Snow conditions for descent were good and the best conditions we have encountered this year for skiing. No audible failures, collapses, and/or shooting cracks. | • Overcast skies, very light snowfall. • Winds were westerly, light with moderate gusts at all elevations. • Evidence of previous wind transport onto easterly aspects at elevations above 5400 feet. • Air T’s (F) near freezing at Canyon floor and in the mid-twenties at ridgeline elevations during the morning. Later in the afternoon air temps warmed to above freezing on the Canyon floor and into the upper-twenties at ridgeline elevations. | Conducted full snow profile on a 38 degree, easterly aspect in the looker’s right side of the upper Shed 5 starting zone. Elevation at this location was 5970 feet and snowpack height was 103 cm. Snowpack was dry for approximately the upper 2/3rds and moist from 30 cm to the ground. • No significant T gradient was observed in the snowpack at this location. • No propagation in ECT test. • No clean shears or conclusive results in CT tests. • Layer of greatest concern was a 2 cm layer of 0.25 mm facets located 60 cm from the ground or 41 cm from the surface. | NO recent avalanche activity observed. | |
| 2015-01-20 | 18:00:00 | Shed 11 SZ | Steiner | Toured up the Shed 11/ Shed 10.7 mid-ridge to the starting zone of Shed 11. Conducted a full profile at this location. Once completed, descended the same route to the Canyon floor. A well-established surface crust is present, at least to some degree at all elevations. Travel was difficult on ascent and descent due to surface crust along with low density snow beneath the crust. This was particularly problematic at elevations below 5400’ elevation where, once the crust was compromised, our skis would sink through unconsolidated moist snow to the ground surface. No audible fracuring, collapses, and/or shooting cracks. | • Broken skies, no precipitation. • Winds were calm with light west gusts at all elevations. • Evidence of previous wind transport onto easterly aspects at elevations above 5400 feet. • Air T’s (F) in the twenties at Canyon floor and ridgeline elevations during the morning. Later in the afternoon air temps warmed to above freezing on the Canyon floor and into the mid-twenties at ridgeline elevations. and near freezing at ridgeline elevations during the day. | Conducted full snow profile on a 35 degree, southerly aspect just above the starting zone of Shed 11. Elevation at this location was 6380 feet and snowpack height was 166 cm. Snowpack was dry between 55 cm and 166 cm from the ground. Below 55 cm the snowpack was moist. Significant T gradient associated with the upper 20 cm of the snowpack. Below 55 cm snow temperatures were pegged at 0 degrees C or 0.1 to 0.2 degrees above 0 C. • Crusts from both late November and early December exist at this location. Interface between these two crusts consists of 1 mm facets with 4F hardness . • Stability tests at this site consisted of two ECTs. • ECTs propagated full column at 59 cm from ground on top of the December crust. • ECTP 30 (Q1) and ECTP 26 (Q2). • Stability test failure interface appeared to be a very thin layer of 1mm facets and decomposing surface hoar. This was our greatest concern in this profile. | NO recent avalanche activity was observed. | |
| 2015-01-15 | 18:00:00 | Shed 7 West | Steiner | Toured up the looker’s right side of the Shed 7 path to the Shed 7 East path and then up to the mid-ridge between Shed 7 West and East. Continued on ridgeline to the upper starting zone of Shed 7 West. Conducted a full profile at this location. Once completed, traversed ridge back along the ridge to the Shed 7 East and then descended looker’s right on the Shed 5 ridge. A well-established crust still prevalent between 6000 and 5400 feet elevation was difficult to navigate on descent. No audible failures, collapses, and/or shooting cracks. | • Mostly clear skies, no precipitation. • Light west winds with moderate gusts. • Wind transport occurring on easterly aspects at ridgeline elevations. • Air T’s (F) in the twenties at Canyon floor elevations (morning and afternoon) and near freezing at ridgeline elevations during the day. | Conducted full snow profile on the looker’s right side of the main Shed 7 West upper starting zone. This location consisted of a 36 degree southeasterly aspect at approximately 6580 feet elevation. HS= 155 cm. Snowpack dry throughout. Significant T gradient in upper 1/3 of snowpack. • Crust and facet interfaces from both November and December still exist but, at this location, crusts appeared to be decomposing and interfaces appear to be strengthening in comparison to previous (earlier) observations at other locations in the Program Area. • Stability tests at this site consisted of two ECTs. • ECTs did not propagate full column at any depth. • ECTN 5 x2 @ 140 cm from the ground or 15 cm from the snowpack surface. | NO recent avalanche activity was observed. Wind transport occurring- loading easterly aspects. |
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| 2015-01-13 | 18:00:00 | Shed 7 East & West | Steiner | Toured up the looker’s right side of the Shed 7 path to the Shed 7 East path. Continued up the Shed 7 East path to the left flank of a natural soft slab avalanche that occurred on 1/6/2015. Conducted a full profile at this location. Once completed, traversed into the Shed 7 West path to observe runout out distance and avalanche characteristic of natural avalanche activity that had also occurred on 1/6/2015. Ascent conditions were difficult due to unconsolidated snow at elevations below ~5000 feet elevation and a well-established crust at elevations above 5400 feet to our highest elevation of 5640 feet. No audible failures, collapses, and/or shooting cracks. | • Overcast skies, no precipitation. • Light west winds with no wind transport above 5000 feet elevation. • Air T’s in the twenties at all elevations (F). | Conducted full snow profile to the looker’s left flank of a natural avalanche that occurred on 1/6/15 in the lower 1/3 starting zone of Shed 7E. Location consisted of a 35 degree easterly aspect at approximately 5640 feet elevation. HS= 111 cm. Snowpack dry throughout. Profile attached Significant T gradient in upper 1/4 of snowpack. • Layer of greatest concern is the interface of a five (5) centimeter rain and/or melt-freeze crust that formed on 1/6/2015 and 17 cm of 1.5 mm faceted snow beneath it. • Crust and facet interfaces from both November and December still exist but, at this location, crusts appeared to be decomposing and interfaces appear to be strengthening. • Stability tests at this site consisted of two ECTs. Both ECTs (ECTP 3 Q1-, and ECTP 1 Q1-) propagated at the basal layer of the 1/6 crust and the uppermost region of facets located at 101 cm from the ground surface. | NO recent avalanche activity was observed. However, avalanche debris from 1/6/15 was observed in both the Shed 7 East and West paths. Terminus for both paths was around 5K feet. Relative size for both of these avalanches was R1 and destructive size 2 (D2). Crown line elevation for the 7E path was approximately 6K feet (Lower 1/3 of the starting zone). The 7W path avalanche appears to have released at its upper most elevation starting zone and entrained snow from both the center and looker’s left portions of the starting zone. Debris in both the 7E and 7W paths when running remained confined to each path’s creek/gully terrain features. Based on previous observations, we believe both of these avalanches released on the December crust/facet interface. | |
| 2015-01-02 | 18:00:00 | Burnout | Steiner | Toured up the Shed 4C (Burnout) area to the ridgeline and then followed the ridgeline to the looker’s left starting zone of the Burnout Path. Conducted a full profile at 5281 feet elevation with the day’s objective to observe lower elevation starting zone snowpack condition at this location. Descended same route. • Windloading and slab formation occurring at all elevations. • No audible collapsing or shooting cracks. | • Overcast skies, no precipitation. • Moderate west winds with strong gusts at all elevations. • Wind loading/ cross loading actively occurring on easterly/ southeasterly aspects. • Air T’s in the teens (F) at upper elevations and twenties at lower elevations (F). | Conducted test snow profile on a 33 degree southeast aspect at approximately 5300 feet elevation. HS= 67 cm. Snowpack dry throughout. Significant T gradient in upper 3/4s of snowpack. • Layers between 67 and 24 cm consisted of decomposing precipitation particles (F hardness to 4F+ hardness). • Layer between 24 cm and 20 cm consisted of F hardness, 1.0 mm faceted grains • Layer between 20 cm and 0 cm (ground) consisted of a (P-) hardness melt/freeze crust : • Stability tests at this test profile site consisted of two ECTs. Both ECTs (ECTP 17 Q2, and ECTP 13, Q2) propagated at 20 cm between the interface of 1mm faceted grains and a well-established melt/freeze crust. | Recent avalanche debris was observed at approximately 1020 this morning at approximately 2/3 path (5000 feet elevation) in Path 1163. No crowns were observed and upper starting zone(s) were obscured by clouds. | |
| 2014-12-30 | 22:30:00 | Shed 5 | Steiner | Toured up the Shed 4C (Burnout) area to the ridgeline and then followed the ridgeline to the starting zone of Shed 5. Conducted a full profile to the looker’s right of the proper Shed 5 SZ. Descended same route to finish out the day. Comfort level was hampered by sub-zero air temperatures throughout the day but snowpack was deep enough to ascend and descend entirely on skis. Beautiful day overall. | • Clear skies, no precipitation. • Light west winds with moderate gusts at all elevations. • Substantial previous and occurring wind loading/ cross loading on easterly aspects. • Air T’s well below zero (F) at all elevations | Conducted test snow profile on a 30 degree east/ southeast aspect at approximately 5800 feet elevation. HS= 115 cm. Snowpack dry throughout. Significant T gradient in upper 2/3rds of snowpack. • Layers between 115 and 50 cm consisted of new snow (F hardness), mixed forms (4F hardness), and rounding grains (4F+ to 1F hardness). • Layer between 50 cm and 43 cm consisted of 4F hardness, 1mm faceted grains • Layer between 43 cm and 16 cm consisted of a Pencil hardness melt/freeze crust : • Layer between 16 cm and 0 cm consisted of 1.5mm depth hoar. • Stability tests at this test profile site consisted of two ECTs. Both ECTs (ECTP 20 Q2, and ECTP 16, Q2) propagated at 43 cm at the interface of 1mm faceted grains and a well-established, pencil hard, crust. | Relatively small magnitude avalanche activity was observed at approximately 1040 this morning in the upper starting zones of Path 1163 and the Shed 10 Looker’s Left feeder path. Both of these avalanches had recently occurred, consisted of surface wind slab that initiated at approximately 6600 feet elevation on easterly aspects, and terminated at roughly 5600 elevation. Crown heights appeared to be less that ten inches (10”) in height. SS-N-R1-D1.5-I | |
| 2014-12-23 | 00:16:00 | Shed 6/7 Ridge | Steiner | Toured up the lower path of Shed 7 to the Shed 6/7 ridge. Ascent was difficult due to shallow snowpack over ground surface and numerous exposed obstacles. Once we obtained the ridge at 5200 feet elevation we conducted snowpack stability tests between 5300 and 5600 feet in elevation on Test Slopes 1,2, and 3. We also conducted a test profile near the starting zone of Test Slope 2 at 5,400 feet elevation. Descent consisted of very conservative skiing and hiking without skis due to shallow snowpack | • Overcast skies, no precipitation. • Moderate west winds with strong gusts at elevations above 5000 feet elevation. • Wind loading occurring on easterly aspects. • Air Ts below freezing at all elevations. | Conducted test snow profile on a 20 degree easterly aspect at approximately 5400 feet elevation. This location was also where we experienced a very noticeable audible collapse. HS= 126 cm. Snowpack dry throughout. No snow or air temperatures were recorded. Snowpack structure consisted of seven (7) main layers: • Layer 1 (Top): A 66 cm new and old snow cohesive windslab with 4F+ hardness. • Layer 2: A thin layer of facets and decomposing surface hoar. • Layer 3: A 4 cm layer of 1F rounds. • Layer 5: 4 cm melt/freeze crust (Knife hardness). • Layer 6: 45 cm rounds (Pencil hardness). • Layer 7: 6 cm depth hoar (1F hardness) variety of weak layers in the upper 1/3 of the pack. The mid pack was strong and supportive despite a couple of thin weak layers. The lower 1/3 snowpack was weaker than the mid pack with facets and depth hoar comprising the bottom layers. • Stability tests at this test profile site consisted of 2 CTs. CT tests revealed CT 13 Q2, and CT 12, Q2. Failure occurred on the interface between the thin layer facets/ decomposing surface hoar and the upper 66 cm cohesive slab. • Stability tests conducted on Test Slopes resulted in No Results. | Recent avalanche activity was observed at 1030 this morning in the starting zone of SHED 8 . This avalanche occurred sometime between 1030 this morning and 0930 on 12/21/2014. We classified this avalanche as: SS-N-R3D2-U. Crown height averaged 40 cm (16 inches), crown length 300 meters (990 feet). Crown line elevation varied between 1818 m (6000 feet) and 1970 m (6500 feet). Vertical distance between maximum crown elevation and toe of debris was 200 meters (660 vertical feet). Although magnitude of this avalanche was moderate the area covered was large with crown lines extending onto low angled ridgeline terrain. | |
| 2014-03-25 | 00:20:00 | Shed 7 West SZ | Steiner | Ascended the Shed 7 avalanche path to the Shed 7 West path. Followed the main path to approximately 5400 feet (1636 m) elevation and then exited path to the Shed 7 West/ Shed 8 ridgeline. Followed ridgeline to 6020 feet (1824 m) elevation and completed a full profile on a east- northeast aspect. Conditions for skin ascent were good and due daytime warming, descent conditions were poor. No snowpack collapsing, audible failures or shooting cracks observed. | Mostly clear to clear skies with air temperatures in the morning around 200F. Throughout the daytime hours air temperatures climbed to near 500F at all elevations, winds were calm to light from the SW, visibility unlimited, and conditions remained dry. | Conducted a full profile on a 35 degree East/ Northeast aspect at 6200 feet elevation located in a looker’s right path of the Shed 7 West starting zone. Snowpack depth was 377 cm (9 feet). • A significant temperature gradient existed in a portion of the snowpack between the interfaces of 270 cm from the ground and the snowpack above this height and 220 cm from the ground and the snowpack below this height. In this 270 cm to 220 cm portion of the snow pack the snowpack temperature was recording -1 to -20C. Interface snowpack temperatures and temperatures at all other elevations in the snowpack were recording 00C. • Snowpack was moist throughout. • A deep seated layer of concern at this profile location was a 1F mixed form layer sandwiched between two pencil hard crusts located 157 cm from the ground surface or 120 cm from the snowpack surface. • Extended Column stability tests conducted on this deep layer of greatest concern resulted in “No Results” when conducted from the surface of the snowpack or in deep tap tests. Compression tests, however, resulted in conclusive results on this layer at CTH 22 and CTH 23 Q2. • A more surface related layer of concern in this profile location was located 37 cm from the snowpack surface and was related to a mixed form layer beneath a 4F hard crust. Again No ECT results on this layer but Compression Tests conclusively scored CTM 18 and CTM 16 Q2. | • No recent avalanche activity observed. | |
| 2014-03-21 | 08:00:00 | Shed 4 SZ | Steiner | Ascended the looker’s right of the Burnout avalanche path to the east ridge of Snowslip Mountain. Followed ridge to approximately 5,800 feet elevation and conducted a full snow profile. Skinning conditions on ascent were good the entire way with many terrain features well buried and new snow to work with. Trail breaking snow depths varied between 10 and 45 cm. Descent conditions above 5600 feet were fair with 20 to 30 cm new snow with moderate density on a breakable crust. Below 5600 conditions worsened as the new surface snow became far denser and underlying snow was moist and not supportive. Difficult skiing. No shooting cracks, snowpack collapsing, or audible failures. | Overcast skies with light snow and a light to moderate west wind. Wind transport of new snow was occurring at mid and upper ridgeline elevations onto easterly aspects. Air temperatures on the Canyon floor hovered around freezing or just above. Air temperatures at upper elevations remained below freezing all day. In the past week, 30 to 60+ cm of new snowfall has occurred in the Program Area at all elevations. | Conducted a full profile on a 32 degree East/ Northeast aspect at 5,800 feet elevation located in a periphery starting zone of Shed 4. Snowpack depth was 300 cm (10 feet). No significant temperature gradients throughout snowpack. Avg. T -20 C from snowpack surface to 60 cm from surface. From 60 cm below the surface to the ground, steady snowpack temperature at 00C. t Snowpack was dry throughout until the lower 30 cm which was moist. Main layer of concern at this profile location was an interface of a thin decomposing crust and thin layer of mixed form snow grains located at 150 cm from the snowpack surface. This interface was NOT obvious in the profile sidewall and not reactive to ECT or CT stability tests. However, this layer was sensitive to Shovel Shear Tests with repeated results of the Shovel Shear Test. (STE X 2). Please note: the Shovel Shear Test is not quantitative in nature but rather qualitative and is a good indicator of where the snow could fail in shear and associated weak layer strength. Also conducted a Test Pit at 5400 feet elevation on a 37 degree southeast aspect. Snowpack at this location was 170 cm in depth and MOIST throughout. Although layering could still be identified throughout, it appears liquid water has affected the entire snowpack and no layers were reactive to either ECT or CT stability tests. liquid water has affected the entire snowpack and no layers were reactive to either ECT or CT stability tests. | No recent avalanche activity observed. | |
| 2014-03-13 | 16:20:00 | Shed 7 West SZ | Steiner | Toured through the Shed 7 terminus avalanche debris into the Shed 7 East avalanche path. Then skinned the looker’s right side (trim line) of Shed 7East path to about 1/2 path. Exited ½ path hard right into the trees and to the Shed 7 East/ Shed 6 ridge. Once on the ridge, we worked our way to the Shed 7 East weather station for a welfare check and then onto the Shed 7 West starting zone where we conducted a full profile. Touring uphill consisted of fair (frozen surface conditions). Warm conditions in the afternoon created poor skiing conditions at elevations below 6000 feet (1818m). No shooting cracks, collapsing or audible failures observed during today’s field observations. | Mostly sunny skies with light west winds and air temperatures around 320 F or 00C at our profile location (1300). Air temperatures on the Canyon floor hovered in the low 30s F overnight and by late day had reached 400 F (40C). No precipitation in the past 48 hours. | Conducted a full profile on a 30 degree south/ southeast aspect (1600) at the top of the starting zone of Shed 7 West at 6496 feet (1968 m) elevation. Profile was 95 cm in height. • Main layer of concern at this profile location is the interface of a 5 cm thick- 2.0mm facet layer that is on top of an 8 cm 4F+ crust. This interface was located 70 cm from the snowpack surface or 25 cm from the snowpack/ ground interface. • Stability Tests: -ECTP 20, 21 and 25 Q1@ 70 cm from the surface or 25 cm from the snowpack/ ground interface. This was on top of the previous mentioned decomposing crust and 2 mm facets. • This snowpack was isothermal and moist throughout . | Recent size D2 SS avalanche activity observed on a SW exposure of Peak 6996 (False Shields). Crown(s) located at approximately 6000 feet(1818 m) elevation with terminus debris deposited at unknown elevation in the Shields Creek drainage. Also Recent size D2 SS avalanche activity (observed 3/12/14) on the NE exposure of Shed 7 West at elevations between 6400 feet (1939 m) and 6600 (2000) feet. This SS avalanche crown was approximately 200’ (60 m) in length and 30 cm in depth. Terminus was deposited in the upper starting zone above 6200 feet (1879 m) elevation. | |
| 2014-03-11 | 18:00:00 | Shed 11 SZ | Dundas | The focus of today’s tour was to evaluate snowpack structure and conduct snow profile/ stability observations at a high-elevation starting zone. We also needed to perform a maintenance check on the Shed 11 weather station. We toured up the Shed 10. 7/11 ridge to access the weather station and our pit location. T rail breaking was a bit slow due to heavy wet surface snow at all elevations. The canyon floor received 4” and the upper elevations received 8” during Monday’s storm. This snow was deposited warm and wet and became denser as the day progressed due to warm air temps and significant solar input. There was occasional cracking underneath our skis but no shooting cracks or audible failures observed. The downhill skiing portion of our tour was difficult due to heavy wet surface snow and an unsupportable snowpack. | Mostly sunny skies with calm to light west winds and air temperatures reaching 40 F at the Canyon floor and 32 F at our profile location~ located at 6,441 feet elevation. There was no wind transport occurring during our tour. | Conducted a full profile on a 35 degree southeast aspect (1460) at the top of the starting zone of Shed 11 (6,441 ft). Profile was 166 cm in height. • The upper 20 cm of this profile was recent snow that averaged 4F in hardness. This sat on top of a 10cm 1F- hard melt freeze crust. This crust was formed from the recent high elevation rain event. • Below the crust a series of thin crusts sandwiched by rounds or mixed forms made up the next 58 cm. None of these layers were reactive in our stability tests. • The lower 78cm of the pack was our weakest and most concerning. A 19 cm layer of 4F hard mixed forms sat on top of a 9cm melt freeze crust. Below the crust was a 50 cm layer of F+ hard depth hoar. This crust was formed from an extended high pressure event in mid to late January. The weak mixed forms were formed during a cold snap in early February. This crust & overlying weak snow are the basis for the Persistent Slab problem that has plagued our region for the past 6 weeks. This layer of mixed forms and crust were our greatest layer of concern in this profile • Stability Tests: -ECTP 20 & 21 Q1@ 59. This was on top of the crust at the base of the mixed forms. • This snowpack was ISOTHERMAL AND MOIST THROUGHOUT! | Numerous wet loose activity observed today at all elevations. This mostly involved the storm snow from Monday being subjected to warm air temps and significant solar input. No slab avalanche activity was observed in the program area today. | |
| 2014-02-27 | 15:30:00 | Shed 7 West | Dundas | The focus of today’s tour was to evaluate snowpack structure and conduct snow profile/ stability observations at a mid-elevation starting zone in the vicinity of recent avalanche activity. To do this, we initially toured up the lower Shed 7 west path before completing our climb in the trees lookers left of the path. T rail breaking was relatively easy with minimal ski penetration. Surface snow was wind affected and became denser as the day progressed due to warm air temps. There was occasional cracking underneath our skis but no shooting cracks or audible failures observed. | Partly cloudy skies throughout the day with calm to light west winds and air temperatures hovering around freezing at the Canyon floor and at our profile location~ located at 5,788 feet elevation. There was no wind transport occurring during our tour. | SNOWPACK OBSERVATIONS: Conducted a full profile on a 25 degree east aspect (900) on the lookers left of Shed 7West (5,788 ft). Profile was 172 cm in height. • The upper 32 cm of this profile was recent snow that averaged F in hardness. This sat on top of a 1cm pencil hard melt freeze crust. Beneath the crust were 33 cm of facets and mixed forms which sat on top of a 1F hard decomposing crust which was 2 cm thick. This lower crust was formed in mid-January and was the bed surface for the recent mid elevation avalanche activity in Shed 7 west. The facets above the lower crust were our greatest layer of concern in this profile. • A thin layer of F hard facets was immediately below the above mentioned crust. Below the facets the remaining 98 cm of the pack was comprised of facets, mixed forms and depth hoar. All of the layers in the lower 98 cm were gaining strength and averaged 1F- hardness. • Stability Tests: -ECTP 19 & 22 Q2@ 138. This was immediately below the upper 1 cm crust. ECTP 23 & 25 Q2 @ 113 • The only significant T gradient in the snowpack was located in the top 20 cm. | No avalanche activity observed in the program area today. | |
| 2014-02-19 | 18:00:00 | Shed 4C | Dundas | The focus of today’s tour was to evaluate snowpack structure and conduct snow profile/ stability observations at a low elevation starting zone. To do this, we toured to a similar aspect and elevation of the Shed 4C/ Burnout avalanche prone area located on the East end of the Program Area. T rail breaking was moderately difficult with 30cm of new snow sitting on somewhat supportable combination of crusts and soft snow. Surface snow was wind affected and very soft surface wind slab conditions had developed in this area. There was cracking underneath our skis but no shooting cracks or audible failures observed. | Partly cloudy skies throughout the day with gusty west winds and air temperatures hovering around freezing at the Canyon floor and -30C at our profile location~ located at 5,200 feet elevation. Wind transport of recent snow was occurring with active wind loading on easterly aspects throughout the day at all elevations. | Conducted a full profile on a 27 degree east-south aspect (1150) in the starting zone of Shed 4C (5,400 ft). Profile was 137 cm in height. • The upper 18 cm of this profile was new snow that averaged 4F in hardness. This sat on top of a 1cm layer of 0.50mm, F+ hard facets. Beneath the facets was a 1F- hard decomposing crust which was 5 cm thick. This surface slab/ facet/crust interface was our greatest layer of concern in this profile. • A series of thin, relatively hard decomposing crusts and thin weak faceted layers comprised the rest of the pack down to 40 cm from the ground. Only one of these numerous crust/facet interfaces proved to be reactive in our stability tests and this was located at 75 cm from the ground, • The lower 40 cm of this profile was comprised of 1F hard depth hoar. The strength of the lower 70 cm of the pack was surprising and certainly the strongest lower portion of a snow pack that we have seen this season. • Stability Tests: -ECTP 12 Q2@ 109. This was in the thin faceted layer just below the surface slab. ECTP15 Q2 @ 75. This was in the series of crust/facet interfaces. CT8 & 9 Q2 @ 109 CT 11(x2) Q2 @ 75 • No significant T gradient existed in the snowpack. | We observed a natural avalanche cycle in John F. Stevens Canyon that started Sunday, 2/16/14 and has continued through today. Small to moderate sized slab avalanches have been observed in the Program Area’s upper elevation starting zones. Associated debris has terminated in the mid to lower path elevations of most paths. The furthest running avalanche debris was in the Shed 7 path and it terminated at the upper edge of the Shed 7infrastructure (4400 ft.) Several paths not associated directly with the Program Area, in particular the Grizzly Gulch Headwall (2/16/14) and JAVA Mountain (2/19/14) exhibited larger magnitude slab avalanche (D2+) activity. We have observed no avalanche activity at low and mid elevation starting zones since 2/12/14. |
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| 2014-01-23 | 20:45:00 | Shed 11 Path & SZ | Steiner | Hiked up the Shed 11 avalanche path to approximately 5500 feet (1667 m) elevation and then skinned to approximately 6,200 feet (1879 m) elevation where we conducted a full profile in the SZ of Shed 10.7. Surface snow conditions consisted of a trace of new snow/ surface hoar on a well-established melt/freeze crust. Crust was supportable and skiing was FAIR on ascent and descent. | High pressure entrenched over the Program area with Inverted weather conditions and high stratus ceiling around 7,000 feet (2121 m) elevation. Light west winds and no precipitation. Air Ts between 200F and 300F. Overcast conditions transitioned to mostly cloudy by the end of the day. | Conducted full profile on a 34 degree east aspect in the starting zone of Shed 10.7 (Profile Attached). Profile was 230 cm in height and when separated into thirds: • The upper 1/3rd averaged 1F in hardness with our greatest layer of concern being on the surface and comprised on new snow and surface hoar. This combination of snow grains is layer on top of a well-established 8 cm Melt/freeze crust. Grain size in the upper 1/3 varied between 2 mm and 0.25 mm. • The middle 1/3rd also averaged 1F hardness and was comprised of mainly mixed forms and round snow grains with sizes ranging between 0.25 mm and 1.0 mm. No major concerns in the middle 1/3. • The lower 1/3rd averaged 4F+ hardness and was comprised on facets, decomposing facets, and depth hoar. It is in the lower 1/3, at approximately 52 cm from the ground, that our greatest layer of concern exists. This is comprised of an interface between 1.0 mm decomposing facets and 2.0 mm well defined faceted grains. • Stability Tests: ECTN 12 @ 220, ECTP 30 Q1 @ 52 cm (Deep Tap Test). • A significant T gradient existed only in the upper 10 cm of the snowpack in this profile location. | The Shed 11 glide crack, which was last observed by BNSF Avalanche Safety on 1/16/2014, has massively failed. The date and time of failure are unknown- but it was before yesterday and after last Thursday afternoon. The failure of this glide crack resulted in a “Glide Slab” which started at approximately 6250 feet (1894 m) elevation and terminated at approximately 4160 feet (1261 m) elevation. Debris was wet and terminus was approximately 100 lineal feet upslope from the upper edge of the Shed 11 infrastructure. Crown width was approximately 330 feet (100 m) and Crown height averaged four (4) feet (120 cm). Classified as: GS-N-R3D2.5-G |
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| 2014-01-16 | 21:30:00 | Shed 7 West SZ | Steiner | A beautiful day. No audibles, shooting cracks, or collapsing. Light south winds, scattered clouds, and air temperatures in the upper 20s and lower 30s. Surface snow below 5000 feet (1515 m) was comprised of a supportable curst and perfect for ski crampons on ascent. Between 5000 and 6000 feet (1818 m) surface snow was slightly sun affected on solar exposures and wind affected from previous winds. Also, on solar aspects surface snow was becoming moist by late morning. Descent conditions were FAIR to GOOD with wind affected snow, sun crusts, and on shaded (non-wind affected) aspects… creamy powder and graupel. | • Few clouds with no precipitation • Light south winds with minimal snow transport. • Air Ts into the 30s lower elevations and upper 20s F at upper elevations. | Conducted full profile in the starting zone of Shed 7 West. *Note: Cornice size in Shed 7 West is significant and exposure to objective hazard in regards to the Shed 7 cornice was avoided while conducting profile observations.. Profile was 178 cm in height and when separated into thirds, the upper 1/3rd averaged 4F, the middle 1/3rd 1F and the lower 1/3rd 4F-. Our greatest layer of concern consisted of a deep seated decomposing facet layer approximately 60 cm from the ground surface. This layer was sandwiched between two (2) other layers of decomposing facets. The upper decomposing facet layer consisted of snow grains 0.25 mm in size and 1F+ hardness. The lower decomposing facet layer consisted of snow grains 1.0 mm in size and exhibited 4F+ hardness. The hardness of the sandwich layer, our layer of greatest concern, was FIST and grain size was 1.0 mm. Stability test consisted of ECTs and CTs. Layer of greatest concern failed at CTH 21 (Q2) and ECTP 23 (Q2). *In order to get an ECTP result on this layer required removing the upper 30 cm of the snowpack from the ECT column so the snowpack height between the layer of greatest concern and the column surface was 88 cm instead of 118 cm (The entire height of the original column). No significant T gradient existed in this profile location. | • On drive to Essex, two (2) old individual crowns observed on steep easterly facing unsupported face of the Cascadilla Headwall (Nyack Mountain). Both were approximately 60m in length and located on the upper 1/3 of the rock face. • Glide crack in the SZ of Shed 11 has nearly doubled in length and now spans approximately ¾ of the Shed 11 SZ . This was first observed on 1/1/2014. • Old avalanche debris located at 1/2 path in Path1163 and in the bottom of the Shed 7 West bowl. Debris deposit for both these observations iss small relative to path. |
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| 2014-01-07 | 22:30:00 | Shed 5 SZ | Steiner | Toured up the Shed 6/7 ridge to starting zone elevation of Shed 7 East. Full profile conducted near the starting zone of Shed 5. Below 5200 feet (1576 m) elevation, surface snowpack consist of 4” (10 cm) to 6” (15 cm) of low density snow on top of a well-established rain crust deposited on 1/3/2014. Above 5,200 ridges consist of scoured /wind affected snow and hard slab formation in starting zones. No collapsing or audible failures- isolated cracking in top 2” (5 cm) on isolated small/ steep convex terrain features. | • Partly cloudy skies with no precipitation • Light west winds with minimal snow transport. • Air Ts in the teens and twenties F at all elevations. | Conducted full profile near the starting zone of Shed.5 on an easterly aspect 27 degree slope. This was a conservative location and perhaps not the best location for a profile in regards to actual starting zone snowpack conditions. Well established hard slab conditions in the SZ of Shed 5. Profile was 114 cm in height and snowpack consisted of a thin 2” (5 cm) 1F layer on the surface that was resting on less hard snow (4F) in the upper 1/3 of the snowpack. The middle 1/3 was harder (1F) and the lower 1/3 consisted, once again, of less hard snow (4F-) Snow grains throughout the upper 2/3rds of the snowpack were small (0.25 mm) mixed forms or decomposing facets. The lower 1/3 of the snowpack consisted of decomposing facets (0.50 mm) and depth hoar (1mm). Stability test consisted of ECTs and CTs. ECTP 5 and CT1 at the base of the surface 2” (5 cm) 1F wind slab. No other ECTP results. CT29 Q2 result at our layer of greatest concern which lies in between the lower and mid1/3 of the snowpack… This layer interface is between decomposing facets and harder midpack slab. Only significant T gradient recorded was in a 10 cm increment between lower 1/3 and mid 1/3 of the snowpack. | • Glide crack has formed in top of the Shed 11 SZ. This spans approximately 1/2 of the Shed 11 SZ and was first observed on 1/1/2014. Photo Attached • Old avalanche debris located at 2/3 path in Path1163. Debris deposit is small relative to path and no visible crown was observed. • Older crown observed in Sheep Creek from Hwy 2, on the lower 1/3 of an easterly aspect starting zone of Snowshed Mountain. Approximate elevation: 6800 feet (2061 m)? Approximate depth= 1 m. Approx. width= 100 m. Appears to be a natural release. *Can be observed driving W on Hwy 2- just past Shed 11. Photo Attached. |
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| 2014-01-02 | 16:30:00 | Shed 7 East | Steiner | Toured up to the Shed 7 East weather station to repair a broken guy-wire and straighten the listing weather station mast. Also conducted a test profile above the station on a north aspect at 6340 feet (1921 m). Tuesdays low elevation wet snow has been transformed into a melt freeze crust below 5200 feet (1576 m) elevation. Strong west winds have left windward aspects either scoured or in a sastrugi form. Ski crampons were helpful on the ascent and years of experience skiing rough conditions made the descent tolerable. No collapsing, audible failure or shooting cracks in the snowpack were encountered on tour. No natural avalanche activity observed. | • Overcast skies with partially obscured visibility at sz elevations. • Strong West winds… WIND LOADING occurring on Easterly Aspects. • Air Ts below freezing at all elevations. | Conducted test snow profile on a 30 degree northerly aspect at 6340’ elevation. Aspect was 70 and HS= 160 cm. Snowpack at this location was dry throughout. Snowpack consisted of a variety of weak layers in the upper 1/3 of the pack. The mid pack was strong and supportive despite a couple of thin weak layers. The lower 1/3 snowpack was weaker than the mid pack with facets and depth hoar comprising the bottom layers. Stability test consisted of ECTs and CTs. No propagation was observed with the ECT tests and CT tests revealed Quality 2 and 3 failures in the upper 1/3 of the pack with moderate to hard force. We determined that the snowpack in this location was strong. | No natural avalanche activity observed. | |
| 2013-12-26 | 16:30:00 | Shed 4C (Burnout) | Dundas | Toured up to the starting zone of Shed 4C (Burnout). Objective was to conduct a full profile at a mid-elevation starting zone to compare this snowpack to the profile that I conducted last week. Warm air temps and high humidity were responsible for making the surface snow wet, heavy and sticky from the valley floor to my pit location at 5300’. Numerous wet loose “roller balls” occurred both naturally and were triggered by tree bombs, uphill and downhill skiing. | • Overcast skies. • Light west winds. • Warn air Ts throughout the day with Ts above freezing in the valley floor and at the pit location. • Surface snow had been worked over by recent Southwest winds. | Conducted full-depth snow profile on a 35 degree slope at 5300 ft elevation. Aspect was 1200 and HS= 81 cm. Snowpack was moist throughout and WEAK! Boot penetration was to the ground at the pit location. Snowpack consists of 2 thin crusts located 16 cm and 54 cm from the ground. These crusts are sandwiched by weak layers of facets, mixed forms, rounds and depth hoar. Layer of greatest concern is a 5 cm layer of 1.0mm facets located directly above the lowest crust. Significant T gradient was recorded only in the upper 10 cm of the snowpack. Stability test consisted of ECTs and CTs. No propagation was observed in the ECT tests. CT tests revealed failure in 4 distinct layers. CT 6,8,8 Q2@ 55 cm from ground on top of the uppermost crust CT13,15,16 Q2@ 43 cm from ground in a 16 cm layer of 4F mixed forms CT 21,22 22 Q2@ 21 cm from ground in a 5cm layer of facets sandwiched between depth hoar and a 1F slab CT 23,23,25 Q2 @ 15 cm from ground in a 15 cm layer of depth hoar | No slab avalanche activity observed. Numerous wet loose roller balls observed that entrained only the surface snow. | |
| 2013-12-26 | 16:30:00 | Shed 4C | Steiner | Toured up to the starting zone of Shed 4C (Burnout). Objective was to conduct a full profile at a mid-elevation starting zone to compare this snowpack to the profile that I conducted last week. Warm air temps and high humidity were responsible for making the surface snow wet, heavy and sticky from the valley floor to my pit location at 5300’. Numerous wet loose “rollerballs” occurred both naturally and were triggered by tree bombs, uphill and downhill skiing. | • Overcast skies. • Light west winds. • Warn air Ts throughout the day with Ts above freezing in the valley floor and at the pit location. • Surface snow had been worked over by recent Southwest winds. | Conducted full-depth snow profile on a 35 degree slope at 5300 ft elevation. Aspect was 1200 and HS= 81 cm. Snowpack was moist throughout and WEAK! Boot penetration was to the ground at the pit location. Snowpack consists of 2 thin crusts located 16 cm and 54 cm from the ground. These crusts are sandwiched by weak layers of facets, mixed forms, rounds and depth hoar. Layer of greatest concern is a 5 cm layer of 1.0mm facets located directly above the lowest crust. Significant T gradient was recorded only in the upper 10 cm of the snowpack. Stability test consisted of ECTs and CTs. No propagation was observed in the ECT tests. CT tests revealed failure in 4 distinct layers. CT 6,8,8 Q2@ 55 cm from ground on top of the uppermost crust CT13,15,16 Q2@ 43 cm from ground in a 16 cm layer of 4F mixed forms CT 21,22 22 Q2@ 21 cm from ground in a 5cm layer of facets sandwiched between depth hoar and a 1F slab CT 23,23,25 Q2 @ 15 cm from ground in a 15 cm layer of depth hoar | No slab avalanche activity observed. Numerous wet loose rollerballs observed that entrained only the surface snow. |
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| 2013-12-19 | 16:30:00 | Shed 4C (Burnout) | Dundas | Toured up to the starting zone of Shed 4C (Burnout). Objective was to conduct a full profile at a mid-elevation starting zone along with observing how the overnight new low density snow was adhering to the underlying melt freeze crust. The near surface melt freeze crust was only supportable on skis above 5200 feet (1576m) elevation. At the 5300” pit location boot penetration was to the ground. | • Clear sunny skies. • Calm winds. • Cold air Ts throughout the day with Ts around 0F in the valley floor and at the pit location. • Surface snow was mostly unaffected by the overnight moderate-strong North winds. | Conducted full-depth snow profile on a 34 degree slope at 5300 ft elevation. Aspect was 1350 and HS= 61 cm. Snowpack consists of 3 prominent crusts which are all sandwiched by facets, mixed forms, depth hoar or overnight low density snow. Layer of greatest concern consists of an 8 cm layer of 1.0mmfacets located between the 2 lowest crusts. Significant T gradient was recorded only in the upper 10 cm of the snowpack. Stability test consisted of ECTs and CTs. No propagation was observed in the ECT tests. CT tests revealed failure directly below each crust. CT12 Q2@ 46 cm from ground CT14 Q2@ 19 cm from ground CT18 Q2@ 10 cm from ground | No avalanche activity observed. | |
| 2013-12-17 | 15:46:00 | Shed 11/10.7 Ridge | Steiner | Toured up the Shed 10.7/11 ridge to the south ridge of Running Rabbit Mountain. Snowpack conditions below 5200 feet (1576m) elevation consisted of a 12” to 16” (30-50 cm) melt/freeze snowpack. Between 5200 (1576m) and 5900 (1788m) snow depth increased to near 24” ( 60 cm) and consisted of soft/ wet snow with intermittent wind affected snow (hard slab. AUDIBLE COLLAPSING occurred at approximately 6400’ (1939 m) elevation on a ~30 degree southerly aspect. Descent was manageable and slow due to obstacles buried in, or protruding from, wet/ unconsolidated snow- particularly below 5200 feet (1576m). | • Partly cloudy skies with NO snowfall. • Light westerly winds with no wind transport. • Warm air Ts throughout the day with Ts at or above freezing at all elevations. • Surface snow affected by previous wind all elevations. Old pockets; drifts and isolated pillows of windslab, 20 cm in thickness, remain easy to trigger. | Conducted full-depth snow profile on a 30 degree slope at 6452 ft. (1955m) elevation. Aspect was 1700 and HS= 67 cm. Snowpack consists of rounds, mixed forms, a decomposing crust (30 cm from the ground), and depth hoar beneath the crust. Layer of greatest concern consists of a 33 cm layer of 1.0mm mixed forms located on top of the decomposing crust. Significant T gradient was recorded in the upper ½ of the snowpack. Stability test consisted of three (3) ECTs and resulted in repetitive full-column propagations at the mixed form /decomposing crust interface located 30 cm from the ground or 47cm from the snowpack surface: Test 1: ECTP14 Q2@ 118 cm from ground Test 2: ECTP13 Q2@ 107 cm from ground Test 3: ECTP11 Q1@ 82 cm from ground WE BELIEVE, based on snowpack analysis and conclusive stability test results, that the audible collapsing we experienced is related to the MIXED FORM/ DECOMPOSING CRUST interface located 30 cm from the GROUND. We also believe this is the same crust/facet interface we found in our profile location on 12/12/2013 as both interfaces have similar grain structure and are located approximately the same distance from the ground surface. | NO avalanche activity observed. | |
| 2013-12-17 | 15:46:00 | Shed 10.7/11 Ridge | Steiner | Toured up the Shed 10.7/11 ridge to the south ridge of Running Rabbit Mountain. Snowpack conditions below 5200 feet (1576m) elevation consisted of a 12” to 16” (30-50 cm) melt/freeze snowpack. Between 5200 (1576m) and 5900 (1788m) snow depth increased to near 24” ( 60 cm) and consisted of soft/ wet snow with intermittent wind affected snow (hard slab. AUDIBLE COLLAPSING occurred at approximately 6400’ (1939 m) elevation on a ~30 degree southerly aspect. Descent was manageable and slow due to obstacles buried in, or protruding from, wet/ unconsolidated snow- particularly below 5200 feet (1576m). | • Partly cloudy skies with NO snowfall. • Light westerly winds with no wind transport. • Warm air Ts throughout the day with Ts at or above freezing at all elevations. • Surface snow affected by previous wind all elevations. Old pockets; drifts and isolated pillows of windslab, 20 cm in thickness, remain easy to trigger. | Conducted full-depth snow profile on a 30 degree slope at 6452 ft. (1955m) elevation. Aspect was 1700 and HS= 67 cm. Snowpack consists of rounds, mixed forms, a decomposing crust (30 cm from the ground), and depth hoar beneath the crust. Layer of greatest concern consists of a 33 cm layer of 1.0mm mixed forms located on top of the decomposing crust. Significant T gradient was recorded in the upper ½ of the snowpack. Stability test consisted of three (3) ECTs and resulted in repetitive full-column propagations at the mixed form /decomposing crust interface located 30 cm from the ground or 47cm from the snowpack surface: Test 1: ECTP14 Q2@ 118 cm from ground Test 2: ECTP13 Q2@ 107 cm from ground Test 3: ECTP11 Q1@ 82 cm from ground WE BELIEVE, based on snowpack analysis and conclusive stability test results, that the audible collapsing we experienced is related to the MIXED FORM/ DECOMPOSING CRUST interface located 30 cm from the GROUND. We also believe this is the same crust/facet interface we found in our profile location on 12/12/2013 as both interfaces have similar grain structure and are located approximately the same distance from the ground surface. | NO avalanche activity observed. |
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| 2013-12-12 | 23:00:00 | Shed 5 Starting Zone | Steiner | Toured up Burnout (Shed 4D) and along the east ridge of Snowslip Mountain to the starting zone of Shed 5. Travel conditions below 5200 feet elevation consisted of breaking 25 cm of medium density snow and being supported by a substantial crust developed between 11/30 and 12/1/13. Above this elevation, buried supportive crust diminishes and surface snow depths increase to ~60 cm or more of unconsolidated snow. On descent we experienced shooting cracks in newly formed windslab but no collapsing or audible failure. | * Partly cloudy skies with NO snowfall. • Moderate (gusting to strong) westerly winds transporting SIGNIFICANT snow (WIND LOADING) onto easterly aspects. • Air Ts near freezing throughout the day. Averaging 00C on Canyon floor and -30C at SZ elevations. • Surface snow affected by wind… By the end of day, WINDSLAB developing at all elevations on easterly aspects. | Conducted full-depth snow profile on a 35 degree slope at 6042 ft. (1831m) elevation. Aspect was 900 and HS= 158 cm. Snowpack consists of rounds, mixed forms, facets, and a decomposing crust 30 cm from the ground. Layer of greatest concern was located 31 cm from the ground and consisted of 2mm well developed facets. Significant T gradient throughout entire snowpack. Stability test consisted of one (1) ECT and resulted in four (4) separate full-column propagations: ECTP14 Q2@ 118 cm from ground ECTP19 Q2@ 107 cm from ground ECTP24 Q1@ 82 cm from ground ECTP26 Q1@ 31 cm from ground A second ECT was not conducted due to time and weather conditions. *These results are an anomaly for us. In seven (7) seasons of conducting profiles in the Program Area, this is the FIRST time we have had more than one (1) full-column propagation during a single ECT… much less four (4)! | Cornice fall at ~6700 ft. (2030m) elevation in the Shed 7 West path appears to have triggered an avalanche on an easterly aspect: U-NC-R1-D1.5. Terminus appears to be ~6200 ft. (1879m) Time of occurrence is unknown but before 0930 on 12/12/13. Also observed other cornice fall activity on an easterly aspect of a sub-ridge of False Shields. | |
| 2013-12-12 | 00:23:00 | Shed 5 SZ | Steiner | Toured up Burnout (Shed 4D) and along the east ridge of Snowslip Mountain to the starting zone of Shed 5. Travel conditions below 5200 feet elevation consisted of breaking 25 cm of medium density snow and being supported by a substantial crust developed between 11/30 and 12/1/13. Above this elevation, buried supportive crust diminishes and surface snow depths increase to ~60 cm or more of unconsolidated snow. On descent we experienced shooting cracks in newly formed windslab but no collapsing or audible failure. | • Partly cloudy skies with NO snowfall. • Moderate (gusting to strong) westerly winds transporting SIGNIFICANT snow (WIND LOADING) onto easterly aspects. • Air Ts near freezing throughout the day. Averaging 00C on Canyon floor and -30C at SZ elevations. • Surface snow affected by wind… By the end of day, WINDSLAB developing at all elevations on easterly aspects. | Conducted full-depth snow profile on a 35 degree slope at 6042 ft. (1831m) elevation. Aspect was 900 and HS= 158 cm. Snowpack consists of rounds, mixed forms, facets, and a decomposing crust 30 cm from the ground. Layer of greatest concern was located 31 cm from the ground and consisted of 2mm well developed facets. Significant T gradient throughout entire snowpack. Stability test consisted of one (1) ECT and resulted in four (4) separate full-column propagations: ECTP14 Q2@ 118 cm from ground ECTP19 Q2@ 107 cm from ground ECTP24 Q1@ 82 cm from ground ECTP26 Q1@ 31 cm from ground A second ECT was not conducted due to time and weather conditions. *These results are an anomaly for us. In seven (7) seasons of conducting profiles in the Program Area, this is the FIRST time we have had more than one (1) full-column propagation during a single ECT… much less four (4)! | Cornice fall at ~6700 ft. (2030m) elevation in the Shed 7 West path appears to have triggered an avalanche on an easterly aspect: U-NC-R1-D1.5. Terminus appears to be ~6200 ft. (1879m) Time of occurrence is unknown but before 0930 on 12/12/13. Also observed other cornice fall activity on an easterly aspect of a sub-ridge of False Shields. | |
| 2013-12-10 | 16:30:00 | Shed 6/7 Ridge | Steiner | Toured up the Shed 7/6 ridge to test slope elevations. Travel conditions below 5200 feet (1576m) elevation consisted of breaking 25 cm low density new snow and being supported by a substantial crust (11/30-12/1/13). Above this elevation snow was scoured on windward aspects (westerly) and wind loaded on easterly aspects. Other than intentionally triggered avalanches (details below), we did experienced isolated shooting cracks in upper 25 cm but no collapsing or audible failures. | • Overcast skies with light snowfall. • Light west winds. • Air Ts at all elevations were around 10F in the AM and 15F for the remainder of the day. | Crown profiles conducted on two (2) separate crown lines intentionally triggered on separate test slopes (details in “Avalanche Observations - below). Both crown profiles were similar in layering (note following profile), averaged 350 slope angle, and had south and southeast aspects respectively. Elevations were similar with one crown at 5300 feet (1606 m) elevation and the second at 5500 feet (1666 m) elevation a.s.l. Depth (cm): Crystal Type: Size (mm): Hardness Notes: 0-25 Decomposing/ fragmented snow 0.25 4F 25-67 Mixed forms 0.25-0.50 F Bed Surface Bed Surface Bed Surface Bed Surface @ 64 cm 67-69 Small facets 0.25 1F 69-76 Mixed forms 0.25 1F+ 76-80 Rain Crust 1F+ *11/17-11/18 80-90 Mixed forms 0.25 P- ECTP12@60cm on crown bed surface/ weak layer interface at 5300. ECTX on crown profile weak layer/bed surface interface. | No natural avalanche activity observed. Intentionally skier triggered avalanche in both Test Slope 1 and Test Slope 3. Avalanche in Test Slope I (SS-ASi-R2-D1.5-O) and avalanche in Test Slope 3 (HS-ASi-R2-D1.5). Test slope 1 avalanche fractured at skier’s position and Test Slope 3 fractured 30 lineal feet above skier position. Associated debris ran full path in both Test Slopes. |
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| 2013-12-10 | 16:30:00 | Shed 7 East Ridge | Steiner | Toured up the Shed 7/6 ridge to test slope elevations. Travel conditions below 5200 feet elevation consisted of breaking 25 cm low density new snow and being supported by a substantial crust (11/30-12/1/13). Above this elevation snow was scoured on windward aspects (westerly) and wind loaded on easterly aspects. Other than intentionally triggered avalanches (details below), we experienced isolated shooting cracks in upper 25 cm but no collapsing or audible failures. | • Overcast skies with light snowfall. • Light west winds. • Air Ts on Canyon floor were around 100 F in the AM and 150 F for the remainder of the day. | Crown profiles conducted on two (2) separate crown lines intentionally triggered on separate test slopes (details in “Avalanche Observations - below). Both crown profiles were similar in layering (note following profile), averaged 350 slope angle, and had south and southeast aspects respectively. Elevations were similar with one crown at 5300 feet (1606 m) elevation and the second at 5500 feet (1666 m) elevation a.s.l. Depth (cm): Crystal Type: Size (mm): Hardness Notes: 0-25 Decomposing/ fragmented snow 0.25 4F 25-67 Mixed forms 0.25-0.50 F Bed Surface Bed Surface Bed Surface Bed Surface @ 64 cm 67-69 Small facets 0.25 1F 69-76 Mixed forms 0.25 1F+ 76-80 Rain Crust 1F+ *11/17-11/18 80-90 Mixed forms 0.25 P- ECTP12@60cm on crown bed surface/ weak layer interface at 5300’. ECTX on crown profile weak layer/bed surface interface at 5500’. | No natural avalanche activity observed. Intentionally skier triggered avalanche in both Test Slope 1 and Test Slope 3. Avalanche in Test Slope I (SS-ASi-R2-D1.5-O) and avalanche in Test Slope 3 (HS-ASi-R2-D1.5). Test slope 1 avalanche fractured at skier’s position and Test Slope 3 fractured 30 lineal feet above skier position. Associated debris ran full path in both Test Slopes. | |
| 2013-03-26 | 17:30:00 | SHED 9 SZ | Steiner | Toured up Shed 7 West avalanche path to the Shed 7 ridge and then west into the Shed 9 Starting zone. Ascent conditions were fair and travel was easy- with the use of ski crampons. Descent was fair as surface snow had warmed to moist/ wet consistency. Surface roughness increasing substantially at lower elevations. Vegetative and terrain hazards becoming more prevalent at snowpack surface. | • Mostly clear skies today with a few scattered clouds. • Light west winds. • Air Ts on Canyon floor were in the lower 20s F in the AM and warmed into the mid-30s F by afternoon. • Air Ts at approximately 6000 feet during the afternoon hovered around 32 F. • Solar input significant today | Full profile conducted in the starting zone of Shed 9 on a south/ southeast aspect (140 degrees) 30 degree slope at an elevation of 6800 feet (6800’). Snowpack depth 116 cm and moist in upper most layer and dry for remainder of snowpack. Significant Temperature gradient exited in the upper 16 cm of the snowpack. Upper and mid snowpack at this location was relatively supportive and consisted of rounded grains, a 10 cm melt/freeze crust, and decomposing facets- beneath the MF crust. No significant stability test results on these layers. Greatest concern at this location is related to depth hoar found in the lower 47 cm of this profile. This layer is 47 cm in height, 4F+ in hardness, comprised of 3mm depth hoar and is adjacent to a P hard ice crust/ lens. This layer/ layer interface was not reactive in ECT tests but failed with hard force Q2 shears in CT stability tests. *Please refer to attached Snow Profile. Similar to last week’s observation in the Shed 5 starting zone (March 19th, 2013) we feel the mid-pack at this location appears to be providing supportive structure to the snowpack. | One relatively small soft slab avalanche that had previously released was observed in the starting zone of Shed 9. Debris associated with this slab terminated in the upper 1/3 of the Shed 9 SZ. | |
| 2013-03-19 | 17:30:00 | Shed 5 SZ | Steiner | Toured up the Shed 6/7 ridge to the starting zone of Shed 5. Travel conditions were fair on ascent and poor on descent… Breakable MF crust formed throughout the day and was prevalent on all but the most shaded aspects- which are difficult to find on a southerly aspect Program area. | • Mostly clear skies today with a few scattered clouds. • Light west winds in early afternoon- decreased after 1500. • Air Ts on Canyon floor were in the lower 20s F in the AM and warmed into the mid-30s F by afternoon. • Air Ts at approximately 6000 feet during the afternoon hovered around 30 F. • Solar input significant today... Melt/ freeze crust established on all southerly and non-shaded easterly aspects. | Full profile conducted in the starting zone of Shed 5 on a southeast aspect (110 degrees) 34 degree slope at an elevation of 5800 feet (5800’). Snowpack depth 98 cm and moist throughout. No significant Temperature gradients and not yet isothermal. Mid-pack is comprised of melt/freeze crusts and decomposing facets. No significant stability test results on these layers. Greatest concern at this location is related to depth hoar found in the lower 30 cm of the profile. This layer is 4F- in hardness and failed in both ECT stability tests conducted- WITH the entire back of the column cut out… ECTP15 and ECTP22. When an additional ECT was conducted, without cutting the column back wall into the depth hoar, we observed an ECTX on the depth hoar layer-upper snowpack interface. Based on stability test results, the mid-pack appears to be providing supportive structure to the snowpack at this location. Also, based on these stability test results, we feel that IF the mid-pack support is rapidly compromised, the potential for full-depth avalanche activity exists. | One small wet slab release on a low elevation (l4000’) northerly aspect cut bank of the Middle Fork Corridor. This avalanche occurred sometime yesterday afternoon. No other slab avalanche activity observed today. Wet loose surface snow activity was observed in many locations and all was relatively small in magnitude. | |
| 2013-03-07 | 16:00:00 | SHED 10.7 | Steiner | Toured up the Shed 10.7/ Shed 11 ridge to an elevation of 6,300 feet. Ski ascent conditions were challenging with approximately 10 cm of moist snow on a supportable melt-freeze crust. Ski conditions on descent were fair due to heavy snow and a punchy crust that was marginally supportive. | • Overcast skies and light snow throughout the morning and early afternoon. • Light west winds below 5,800 feet elevation and moderate west winds above 5,800. • Air Ts on Canyon floor were in the low 30s F and at 6,300 feet upper 20s F. • Wind transport of available snow was occurring on EASTERLY aspects. | Profile conducted on a 38 degree southeast aspect (105 degrees) at 6,300 feet elevation. Snow depth was 195 cm and dry throughout except the very bottom was moist. There was no significant temperature gradient throughout the snowpack. Aside from precipitation particles located within the upper 16 cm of the snowpack, the profile snowpack consisted mainly of alternating layers of decomposing facets and decomposing crusts. LAYER OF GREATEST CONCERN was located 65 cm from the snowpack surface and consisted of…. 0.25 mm decomposing facets on a decomposing crust. On this layer, ECT stability test results were ECTP22 and ECTP23, both Q2. A secondary layer of concern was located 130 cm from the surface and Deep Tap Tests on this layer resulted in DTT25 and DTT 27, both Q1. | No natural slab avalanche activity observed. Numerous relatively small soft slab avalanches were triggered intentionally utilizing ski cuts. Most of these were triggered above 5,800 feet elevation on easterly aspects. Greatest crown depth of these avalanches was 25 cm and average crown length 20 meters. Debris ran on well established 3/2/2013 melt/freeze crust and terminated in the path. Associated debris ran a maximum of 70 vertical meters. | |
| 2013-03-05 | 17:00:00 | US HIGHWAY 2 EAST | Steiner | Vehicle based Canyon floor observations today. Focus was to observe the spatial extent, avalanche character, and terrain involved with the 3/2/2013 avalanche cycle. | Beautiful day for avalanche hunting today… Visibility unlimited, few clouds, no precipitation, Canyon floor air temperatures in the teens, and calm winds. Three (3) to six (6) cm new snowfall at Canyon floor elevations in the past 48 hours. | No snowpack observations conducted today. | Multiple soft slab releases on terrain above 5,500 feet (1667 meters) elevation. Evidence of soft slab activity was observed on the ridge between Elk Mountain and Little Dog in Glacier National Park, in the upper starting zone of Shed 9~GNP, and in the Sheep Creek drainage (Northeast aspect of Mount Cameahwait~ Flathead Range). Terminus elevation of all avalanches observed greater that 5,400 feet. Slab avalanche activity observed is suspected of occurring between 3/1 and 3/2/2013 and occurred mainly on unconfined, open sloped terrain with southeasterly to northeasterly aspects. Crown depth and specific avalanche size was difficult to estimate due to viewing distance and recent wind loading. However, an approximate size range would be between D2 and D3. All avalanches observed appeared to be naturally triggered and large enough to kill a human. |
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| 2013-02-26 | 18:00:00 | SHED 7 EAST | Steiner | Toured into the starting zone of Shed 7 East today. Surface snow conditions were scoured on westerly and southerly exposures above 5200 feet elevation. No shooting cracks, collapsing, or audible failures. Travel conditions were good on ascent and descent. * Windloading has been substantial above 5,400 feet elevation in the past few weeks on easterly aspects in the Program area… Terrain features normally recognizable in starting zone locations have been buried or filled in. In numerous locations, surface snowpack slope angle in starting zone locations have been reduced appreciably and in some locations, cornices have grown impressively large (Please refer to attached photo). | Below 5,200 feet elevation, air temperatures averaged in the low 30s F and above 6,000 feet averaged in the lower 20s F. Light to moderate west winds at elevations above 5,400 feet. Wind loading occurring on easterly aspects. Intermittent snowfall throughout the day with no measurable accumulation. | Snow profile was conducted in the starting zone of Shed 7 East on a 32 degree, south easterly aspect (120 degrees). Profile location was at 6323 feet elevation. Snowpack was dry throughout with a depth of126 cm and no significant T gradient. However, a significant temperature gradient was observed between the air T (-6.7 degrees C) and the snowpack surface (-5.3 degrees C). Profile Layers: 126-116 New Snow 0.50 mm 116-90 Rounds 0.50 mm 90-81 Decomposing Facets 0.50 mm CT12 Q1- CT8Q1- & ECTN 81-15 Rounds 0.75 mm 15-0 Depth Hoar 2.0 mm CT19 Q2 & ECTP27/ ECTN As noted, we did get propagation in an ECT in the basal depth hoar… Actually, we are unsure if this was propagation or collapse… Either way, the depth hoar interface is currently well supported by a thick slab of rounds immediately above it. From a Program perspective, the depth hoar layer interface provided the greatest level of interest/ concern for this profile location. From a backcountry touring perspective, the 90 to 81 layer was of greatest concern and likely involved with the intentionally triggered avalanche we initiated (read below). | Intentionally triggered soft slab (SS-ASc-R2D1-I) in Test Slope 2 on a 40 degree southeasterly exposure at approximately 5,600 feet (1697 m) elevation. This released on the interface between newly wind loaded snow and the old snow surface beneath it. Slab thickness averaged 30 cm and width was approximately 20 m. Debris ran full path of test slope. No natural avalanche activity observed. |
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| 2013-02-21 | 17:00:00 | SHED 11 | Steiner | Toured into the starting zone of Shed 11 today. Surface snow conditions were scoured on westerly and southerly exposures above 5200 feet elevation. Above 5,600 feet elevation an unsupportable wind crust had also formed on southerly aspects. Travel conditions were good on ascent and descent. | Below 5,200 feet elevation, air temperatures averaged in the upper 20s F and above 6,000 feet averaged in the lower 20s F. Light to moderate west winds at elevations above 5,400 feet. Wind loading occurring on easterly aspects. Intermittent snowfall throughout the day with no measurable accumulation. | Snowpack profile was conducted in the starting zone of Shed 11 on a 37 degree, south aspect slope. Profile location was at 6250 feet elevation and adjacent to a glide crack that had first been observed on February 7, 2013. Since the 7th, the Shed 11 glide crack has continued to expand both horizontally and vertically. Snowpack was dry throughout with a depth of152 cm and no significant T gradient. However, a significant temperature gradient was observed between the air T (-7.3 degrees C) and the snowpack surface (-4.2 degrees C). Layers within this profile were mainly comprised of melt-freeze crusts interfaced with rounds or decomposing facets. None of these layer interfaces reacted with significant results in either ECT or CT stability tests performed. | No avalanche activity observed. | |
| 2013-02-19 | 17:00:00 | BURNOUT | Dundas | Toured into the east end of the Program Area today and conducted snow profile observations and stability tests in the starting zone of Burnout. Burnout is a relatively low elevation unconfined avalanche prone slope that can produce problematic avalanche activity for Railway operations. Ascent and descent were good although the 12†of new snow was becoming wet and heavy as the day progressed. | The Highway 2 area between West Glacier and Marias Pass received upwards of 12†of new snow in the valley floor from a storm system Sunday and Monday. Snow density was rather light with a 7% water content measured in John F Stevens Canyon. Tuesday the 19th was mostly sunny with calm winds and temperatures in the valley floor in the low 30’s. | Profile location was on a sunny 34 degree SE aspect (120 degrees). HS= 123 cm. 123–94: new snow – F hard 94-79: small rounded grains – 4F 79-72: melt freeze crust - Pencil 72-64: small rounded grains – 1F 64-63: small facets – F THIS WAS OUR LAYER OF CONCERN 63-57: melt freeze crust – P 57-55: decomposing facets – 4F 55-53: melt freeze crust – P 53-0: decomposing depth hoar – 1F Stability tests: CT6@94 Q2 ECTN 5@94 CT9@79 Q2 ECTN 9@79 CT13@63 Q1 ECTN 14 @63 CT14@56 Q2 ECTN 15@56 | No Recent Avalanche Activity Observed. | |
| 2013-02-12 | 17:00:00 | SHED 5 | Steiner | Toured into the lower easterly orientated terrain of the Shed 5 starting zone today. Surface snow conditions were either scoured or comprised of crusts on westerly and southerly aspects. Easterly aspects above 5,400 feet elevation were being wind loaded by moderate to strong westerly winds. Travel conditions were good on ascent and fair on descent. | Air temperatures in the upper 20s F at elevations below 5,200 feet elevation. Air temperatures averaged in the lower 20s F at 5,700 feet elevation. Moderate to strong west winds at ridgetop elevations- wind loading actively occurring on easterly aspects. Intermittent snowfall throughout the day with no measurable accumulation. | Snow profile conducted at 5700 feet elevation on a 37 degree slope with an easterly an aspect (100 degrees). Snowpack depth at profile location measured 158 cm. Similar to last week, at this location although numerous layer interfaces in the profile existed- no layer was of great concern in regards to instability. Again, we did identify a well-defined 1.0mm graupel layer intermixed with decomposing facets located 24 cm from the snowpack surface. In profile Compression and Extended Column stability tests this layer exhibited poor fracture character and ratings of CT11 Q2- & ECTN5. | We did intentionally trigger a relatively small soft slab avalanche in Test Slope 2 on a SE exposure at approximately 5,600 feet elevation. This slab, based on debris character was beginning to form hard slab characteristics but was still relatively soft at time of triggering. SS-ASi-R1-D1-I. Maximum slab thickness was 25 cm and crown width was approximately 25 meters. Lineal run was approximately 100 meters. Interface grain type remains unknown, but we expect, based on profile layer observations, it was related to a layer of decomposing facets/ graupel. NO natural avalanche activity was observed. | |
| 2013-02-05 | 16:00:00 | SHED 7 WEST | Steiner | Toured into the upper starting zone of Shed 7 West today. Surface snow conditions were moist below 5200 feet elevation and wind affected at elevations above 5,200 on south and westerly aspects. Travel conditions were fair and skiing conditions good. | Air temperatures in the mid to low 30s F at elevations below 5,200 feet elevation. Air temperatures cooled into the upper 20s F above 6,000 feet elevation. Light to moderate west winds at ridgetop elevations- wind loading occurring on easterly aspects. Intermittent snowfall throughout the day with no measurable accumulation. | Snow profile conducted at 6466 feet elevation on a 35 degree slope with a northeast aspect (60 degrees). Snowpack depth varied due to rocky ground surface and measured between 230 cm and 170 cm. Although numerous layer interfaces in the profile existed, no layer was of great concern in regards to instability. We did identify a well-defined 1.0mm graupel layer located 25 cm from the snowpack surface- but this was unimpressively reactive in stability tests- CT15 Q2- & ECTN5 with poor fracture character. | Recent wet-loose debris located in Path 1163. Debris terminus was approximately 2/3 path and destructive size (based on debris) was 1.5. No slab avalanche activity was observed. | |
| 2013-01-31 | 17:00:00 | SHED 10.7 | Steiner | Toured into the starting zone of Shed 10.7 today traveling up the ridge between Path 10.7 and 11. Jason Griswold joined us from GNP- Great having you along Jason- thanks for joining us. Skiing conditions on ascent and descent were fair. | Air temperature on Canyon floor hovering around 34 degrees F with light snow and light west winds. Between 5,200 and 6,000 feet elevation: light snowfall, moderate west winds i and air temperatures below freezing. 6,000 feet and above, winds decreased on the aspect we were ascending (SE), air temperatures were below freezing, and light to moderate snowfall occurred throughout the day. | Profile location was on a 31 degree southeasterly aspect (160 degrees) at 6470 feet a.s.l. HS= 150 cm. Layer of greatest concern in the profile existed within the upper 50 cm of the snowpack and consisted of a 4F to F hard slab sitting on 0.5 mm facets resting on a melt-freeze crust formed in mid-January. Stability test results on this layer resulted in ECTN 15 Q2 and ECTP 11 Q1. A significant temperature gradient did exist in the adjacent 25 cm above this interface. | No recent avalanche activity observed. West winds are loading easterly aspects above 5,200 feet elevation. Cornice drops on easterly aspect starting zones resulted in no slab release. Isolated slab propagation and cracking on easterly aspects of small terrain features. There was/is a dense slab with depths greater than 30 cm forming on exposed easterly aspects. | |
| 2013-01-29 | 17:00:00 | SHED 7 WEST | Steiner | Toured into Shed 7 West today traveling up the east ridge of Snowslip from Burnout. East winds were biting cold but sun was out and touring conditions were good… As long as you were dressed warm… Thank goodness for hand warmers. | Arctic air was spilling over from the east and along with it… Cold air temperatures and moderate east winds. Air temperatures on the Canyon floor hovered between 6 and 8 degrees F and no precipitation. Air temperatures at ridgetop elevations averaged -4 F with a 10-15 mph east wind. Skies were broken and no precipitation. | Profile location was on a 35 degree southerly aspect (170 degrees) at 6508 feet a.s.l. HS= 119 cm. Although our profile had layers embedded within it, the layer of greatest concern was the snowpack surface which was comprised of new snow and 1 to 3 mm Surface Hoar. Stability test results: ECTN 6 @ 23 cm from the snowpack surface. CTM 12 Q2- @ 37 from snowpack surface. CTH 22 Q3 at column interface with ground. | No Recent Avalanche Activity Observed. HOWEVER, SOUTHWEST to West aspects have been loaded near the ridgeline and wind deposited snow on leeward aspect of small terrain features near ridgeline elevations were producing shooting cracks and sudden collapse. | |
| 2013-01-23 | 17:00:00 | BURNOUT | Steiner | Toured into the east end of the Program Area today and conducted snow profile observations and stability tests in the starting zone of Burnout. Burnout is a relatively low elevation unconfined avalanche prone slope that can produce problematic avalanche activity for Railway operations. Surface snow conditions were variable and had previously been wind affected. In shaded areas, up to 2 cm of small faceted snow grains were deposited on a breakable crust, In other shaded areas, but with more of a solar dominated aspect, a 1 cm or less surface breakable crust existed. Finally, on solar aspects that were receiving direct sunlight during observations, a moist melt-freeze crust was present. | High pressure continued to dominate weather in the Program Area today- along with the rest of the region. Skies were broken; wind was mostly calm with a light occasional breeze from the east. Average air temperature was around 0 degrees C. No recent snow accumulation. | Profile location was on a solar exposed 35 degree SE aspect (120 degrees). HS= 60 cm. 0-1 cm= Wet Round Grain Clusters. 1.0 mm W F Hardness 1-38 cm= Rounding Grains. 1.0 mm M F Hardness 38-39 cm= Buried Crust. M P Hardness 39-49 cm= Small Facets (0.50 mm). 0.50 mm M F Hardness 49-50 cm= Buried Crust. 1F Hardness 50-59 cm= Mixed Forms. 1.0 mm M F Hardness 59-60 cm = Melt-Freeze Crust. M 4F Hardness Stability tests provided poor results as wet rounded grain clusters at the base of both the Compression and Extended Column test kept collapsing after column isolation and the entire column would tip into the pit. | No Recent Avalanche Activity Observed. | |
| 2013-01-08 | 15:00:00 | JFS Canyon | Steiner | Toured up the Shed 6/7 ridge to the starting zones of Test Slopes 1, 2, and 3. These test slopes are located at mid-elevation for the forecast area and provide excellent representative information in regards to snowpack stability and likelihood of triggering. Skiing conditions on ascent were and descents were certainly wind affected but in good condition for travel. | Up to 30 cm new snow in previous 36 hours. Strong to moderate west winds at all elevations. Air temperatures averaged between -2 C at Canyon floor elevations to – 4 C at snow profile location. Wind loading had previously occurred and continued to occur entire day during observations. Light snow accumulations at all elevations throughout the day. | Profile conducted at 1500. Location an not optimal site due to snowpack stability concerns. Finding a safe, representative profile location took us to a lower elevation slope. Main focus to indentify preserved buried NSF on previously scoured easterly aspects (Dec 24-25/ 12) and SH that formed Jan 2-3/ 13. HS= 140 cm… 1-2 mm decomposing SH layer was located approximately 34 cm beneath snowpack surface on an easterly aspect 35 degree slope at 1660 m (5477 ft). Buried scoured/ NSF interface not found. Stability tests on SH layer resulted in ECTN 10 and CTM Q2 x2. | Although numerous attempts to trigger test slopes utilizing belayed ski cuts and cornice drops- no results. Propensity to propagate seems to be lacking in the deep windslab areas we were testing. Observed one small slab release on NE aspect of the Shed 7 SZ at ridgeline. (U-N-R1-D1-U). Appeared to be associated with new snow accumulations. Also, a previous cornice fall was observed in the Shed 7 West path. This did not seem to initiate a slab release but cornice debris ran vertically 300 m (1000 ft) or about 1/3 the lineal path distance of Shed 7 West. | |
| 2013-01-04 | 15:32:00 | SHED 11 | Steiner | Toured up the Shed 10.7/ 11 ridge to the Shed 11 weather station to conduct needed repairs. Skiing conditions on ascent were difficult due to approximately 20 cm of new low density snow deposited on a harder old snow surface. Conditions for descent were excellent in terms of skiing quality; however,snowpack has settled out significantly at elevations below 5200 feet elevation and obstacles beneath the snowpack are becoming a greater hazard. | High pressure event occurring… clear skies, valley air temperatures ranging between the single digits and twenties F, no wind, and no new snow in past 24 hours. Ridgetop air temperatures climbed above freezing on solar aspects and on shaded aspects into the upper 20s F. Significant T inversion occurring with low stratus layer development around 5500 feet elevation. | No profiles or stability tests conducted due to focus on weather station repair. However, significant Surface Hoar (SH) development on solar aspects between 5200 and 5700 feet elevation. On ascent, SH was wide spread up to 10 mm in size. On descent, it appeared SH exposed to solar input had been destroyed; however, SH was well preserved on easterly aspects and in shaded areas behind trees. Although not observed, believe near surface faceting (diurnal recrystalization) is occurring on solar aspects- may develop a particularly problematic weak layer on easterly aspects that had bee scoured by east winds on 12/24-25/2012. Also, although not observed, believe SH is developing and being preserved on steeper, more shaded aspects in the mid to upper elevation starting zones within the Program Area… I.e.: Lookers left- Path 1163, Infinity, Shed 9, Shed 8, and both Shed 7 W/ E. | Observed one small loose snow avalanche that occurred on 1/3/2013 in the starting zone of Shed 11. This initiated at the rock outcrop on the lookers right of the upper starting zone and ran an unknown distance. Snow entrained appeared to be new snow (N-LS-R1-D1-I). | |
| 2013-01-03 | 15:32:00 | SHED 11 | Steiner | Toured up the Shed 10.7/ 11 ridge to the Shed 11 weather station to conduct needed repairs. Skiing conditions on ascent were difficult due to approximately 20 cm of new low density snow deposited on a harder old snow surface. Conditions for descent were excellent in terms of skiing quality; however, snowpack has settled out significantly at elevations below 5200 feet elevation and obstacles beneath the snowpack are becoming a greater hazard. | High pressure event occurring… clear skies, valley air temperatures ranging between the single digits and twenties F, no wind, and no new snow in past 24 hours. Ridgetop air temperatures climbed above freezing on solar aspects and on shaded aspects into the upper 20s F. Significant T inversion occurring with low stratus layer development around 5500 feet elevation. | No profiles or stability tests conducted due to focus on weather station repair. However, significant Surface Hoar (SH) development on solar aspects between 5200 and 5700 feet elevation. On ascent, SH was wide spread up to 10 mm in size. On descent, it appeared SH exposed to solar input had been destroyed; however, SH was well preserved on easterly aspects and in shaded areas behind trees. Although not observed, believe near surface faceting (diurnal recrystalization) is occurring on solar aspects- may develop a particularly problematic weak layer on easterly aspects that had bee scoured by east winds on 12/24-25/2012. Also, although not observed, believe SH is developing and being preserved on steeper, more shaded aspects in the mid to upper elevation starting zones within the Program Area… I.e.: Lookers left- Path 1163, Infinity, Shed 9, Shed 8, and both Shed 7 W/ E. | Observed one small loose snow avalanche that occurred on 1/3/2013 in the starting zone of Shed 11. This initiated at the rock outcrop on the lookers right of the upper starting zone and ran an unknown distance. Snow entrained appeared to be new snow (N-LS-R1-D1-I). | |
| 2012-12-27 | 16:00:00 | SHED 7 EAST | Steiner | Toured up the Shed 6/7 ridge to the Shed 7 East starting zone. Skiing conditions on ascent and descent were excellent in terms of coverage and skiing quality. | Overcast and broken cloud cover conditions, light snow, and moderate westerly wind, Air temperatures were below freezing all day and -8 C at our profile site. Wind transport of snow onto easterly aspects occurred all day. | Snowpack profile was conducted on a 27 degree southeast aspect at 6377 feet and was located at the top of the Shed 7 East starting zone HS=156 cm. Major layer interface concern exists 93 cm from snowpack surface and consists of a thin layer (<1cm) of small faceted crystals (0.25 mm) that are interfaced with moderately hard snow (1F+) above and a well-established buried rain crust beneath (P). In conducting ECT stability tests on this layer, no results were obtained. However, CT test results were conclusive; resulting in scores of CT23 Q2 and CT29 Q2. Reason for this layer being of greatest concern at this location relates to snowpack structure and potential volume of snow entrained if triggered. Temperature profile conducted indicated an equal temperature snowpack with no significant temperature gradients. Graph of profile is attached to this Field Observations email. | Slab avalanche activity was observed during field observations. Activity observed was both intentionally triggered by us and also natural. Activity observed was limited to the upper 20 cm of the snowpack and occurred on easterly aspects at or above 5,600 feet elevation. Avalanche size observed was small and consisted of newly wind transported snow. | |
| 2012-03-27 | 17:00:00 | Shed 11 | Dundas | Toured up the Shed 10.7/11 ridge to the Shed 11 weather station. Conducted a full profile in the Shed 11 starting zone. Descended the 10.7/11 ridge back to the rail grade. Conditions on ascent and descent were decent above 5500' but poor below that due to thin coverage and wet heavy snow. | Bluebird day with light winds and temps in the mid-30's at the ridgeline. No snow transport occurred today. | Our snow profile was on a SE aspect at 6465'. Total depth of snow was 200 cm. The top 37 cm was wet with the remainder of the pack moist. Temperature profile revealed an isothermal snowpack. -The top 86 cm of the pack consisted of small grained rounded crystals that averaged 4F hard. -Below this was a 1 cm crust that was 1F hard -A 12 cm layer of 1F facets lay below the crust. -Below the facets was a 66 cm slab with a hardness ranging from P- to 1F. -At the bottom of the pack was a 45 cm layer of 4F decomposing depth hoar. Compression test scores: CT 13 & 16 @163 Q2- CT 21 & 21 @ 113 Q1 & Q2+ (this was at the crust/facet interface) CT 26 & 29 @ 101 Q2 & Q2- | One small deep (3-4') slab released at a low elevation where 2 avalanche paths converged. Significant loose snow debris triggered this slide. Sundays above average air temperatures and significant solar input caused numerous loose snow slides and roller/sun balls throughout the area. Except for the above mentioned slab all activity was confined to the surface snow deposited during last weeks storm cycle. | |
| 2012-03-22 | 18:00:00 | Shed 4C, 4D & 5 | Dundas | Ascended the lookers right trees of Shed 4C (Burnout) to the ridgeline above the starting zone. Followed this ridge to the starting zone of Shed 5 where we conducted a full profile. Descent was along the ridgeline and skiers left side of the Burnout face back to the rail grade. Conditions on the ascent and descent were good above 5000' but difficult below there due to this mornings rain on snow event. | Valley floor: Additional 4" of new snow overnight, temps in the low 30's, light rain with calm winds.Upper elevations: Additional 8-10" new snow overnight, temps in the mid 20's, light snowfall with moderate west winds. Significant snow transport occurred throughout the day at the upper elevations. | Conducted a full profile in the starting zone of Shed 5 at an elevation of 5987'. Total depth of snow was 259 cm. - The top 23 cm was F hard storm snow deposited since Sunday the 18th. The depth of this layer is a bit misleading due to the significant amount of settlement that has occurred the past 2 days. - Below this was a 35 cm layer of 1F rounds that was deposited during the warm moist storm of March 15-16. - A 32 cm P hard melt freeze crust formed during the March 7-9 high pressure was next. - Below the crust was a 32 cm layer of 1F- decomposing facets.- A 94 cm layer of mixed forms that were P+ in hardness underlay the facets. - At the bottom of the pack was a 33 cm thick layer of decomposing depth hoar that ranged in hardness from 1F to 4F+.Despite an extremely strong mid-pack Compression Tests revealed concerning failures in layers immediately above and below the 32 cm melt freeze crust.CT 8, 8 & 12 Q1-/Q2 occurred 30 cm from the surface in the layer of rounds above the crust that formed during the warm storm of March 15-16.CT 11, 12 & 12 Q2 occurred 50 cm from the surface in this same layer of rounds.CT 23, 23 & 25 Q2 occurred 100 cm from the surface in the layer of facets that lies beneath the crust ECT tests were inconclusive | One moderate sized slab released from Shed 7 west this morning. Debris ran 2/3 path and left a gouged snow surface which indicates it entrained wet snow. Numerous wet loose slides and roller balls occurred today at all elevations due to the rain/warming event.It was extremely easy to trigger wet loose slides at mid and low elevations. These entrained impressive amounts of snow which ran on top of the rain crust that was formed at mid and low elevations March 15-16. | |
| 2012-03-20 | 16:00:00 | Shed 4C, 4D, 7 East | Dundas | Ascended the lookers right trees of Shed 4C (Burnout) to the ridgeline which we then followed to the Shed 7 East weather station. Performed stability tests in a snow pit just above this station. Had planned on conducting a full profile in the Shed 5 starting zone but decided against this due to the strong winds and cold temps. Descent was along the ridgeline and skiers left side of the Burnout face back to the rail grade. Conditions on the ascent and descent were good. | Valley floor: Temps in the mid to upper 20's F with calm winds and light to moderate snowfall.Ridgeline: Temps in the upper teens to low 20's F with moderate to strong SW winds and light to moderate snowfall. Significant transport of snow occurred throughout the day. | Due to the unfavorable weather we limited our snow profile work to stability tests in a snow pit that we dug on a NE aspect of Shields Creek at approximately 1940 meters. The depth of our pit was 150 cm with the total snowpack depth greater than 3 meters. The top 40 cm of the pack consisted of recent storm snow which sat atop a supportable melt freeze crust that formed March 7-9. CT and ECT results showed our layer of concern to be a thin layer of 0.25 to 0.50 mm facets 70 cm from the surface. This is the same layer that we identified as a layer of concern on March 13 in Shed 7 west. This layer failed on CT 14 and 21 Q2. | No new natural avalanches were observed in the program area. We were able to easily trigger loose snow sluffs in the new storm snow with ski cutting. These sluffs ran long distances on top of the solid underlying melt freeze/rain crust. | |
| 2012-03-14 | 15:49:00 | Shed 7 West | Steiner | Toured today with GNP District Ranger, Jason Grizwold. Ascent route followed the looker's left side of the Shed 7 West path in the trees to the ridgeline and from there to the rock "step" just below the upper corniced ridge of the Shed 7 West path.Descent followed the Shed 7 West path proper to the Canyon floor. Overall, skiing conditions were good on both ascent and descent. | Overcast skies with Canyon floor air temperatures in the 30s F... Air Temperatures at upper elevations were in the mid-20s F. No precipitation and broken cloud cover by the end of the tour. Light to moderate west winds at all elevations with wind transported snow being deposited on EASTERLY aspects. Previous wind loading on EAST aspects had also occurred. | New snow/ wind transported snow interface with melt/freeze crust established last week is tender. Open areas with easterly/ southeasterly aspects and slope angles +/- 38 degrees propagating- shooting cracks from skis and small/ manageable surface slabs. This type of activity most prevalent on small-featured convex rolls and obvious wind pillows.Full snow profile conducted at 6,425 feet (1947 meters) elevation on a SE aspect with a 35 degree slope. HS= 342 cm. Profile depth= 150 cm. Surface snow interface with melt-freeze crust confirmed our earlier ski-based tests failing easily during CT / ECT Tests. Overall, profile mid-pack hardness increased with depth between 4F and P-. However, approximately 100 cm from the surface was a thin, 1 cm, layer of 4F facets that was greatest layer of concern. This layer failed CT27 Q1- and we DID NOT have conclusive result on this layer. A single ECT test did not propagate and resulted in three different ECTN failures corresponding with layers previously identified in CT tests. No significant T gradient in profile. throughout profile. | Other than intentionally triggered small test slope features, no avalanches observed in Program area. SIGNIFICANT cornice fall from yesterday off the Shed 7 West cornice- Debris carried approximately 1000 feet (303 m) to 5,600 feet (1697 meters) elevation. Blocks associated with cornice failure measured 8 ft. by 8 ft. (2.4 m by 2.4 m).... EXCELLENT stability test. | |
| 2012-02-22 | 00:06:00 | Shed 6/7 Ridge | Steiner | Tour Date: 2/21/2012Toured up the Shed 6/7 ridge to gain access to the starting zone elevation of Shed 7 West.Skiing conditions on ascent and descent were excellent in terms of coverage and skiing quality. | Overcast, light snow, and consistent moderate west/ southwest wind, Air temperatures varied between -1 C at the Canyon floor to -3 at ridgeline elevations. Significant wind transport of snow onto easterly aspects occurred all day. | Crown profile conducted at a natural hard slab release in Test slope one indicated an increasing harness slab exists on a poorly bonded melt-freeze crust. Beneath this interface, facets/ mixed forms exist and are also poorly bonded allowing the naturally released slab to step beneath the MF crust interface.Conducted a snow profile on a northerly aspect of “Shield Creek†in an area that was similar elevation/ slope angle to the northerly aspect of Shed 7 West. HS= 340 cm. Profile conducted on upper 190 cm. Major layer interface concern existed 70-74 cm from snowpack surface and consisted of 1-3 mm surface hoar resting on a harder layer of snow beneath. Significant T gradient existed between 20 and 30 cm from snowpack surface.Due to time and conditions only one ECT Stability test was conducted in profile and resulted in an ECTP 12 Q1 on the surface hoar interface located between 70 and 74 cm from the snowpack surface. Video located on GCAC Observations Page… www.glacieravalanche.orgAll mid to upper elevation paths appear to be extremely loaded with wind deposited snow. New snow depth above 6,000 feet (1820 m) was at least 2 feet (60 cm). | Recent slab avalanche activity was observed in several different locations in the Program Area.Beginning with Test Slope 1 located on a SE aspect at 5,600 feet elevation. Test Slope 1 had pulled naturally as a hard slab… HS-N R4D2-O… Video also located on the GCAC Observations Page.Soft slabs had recently released in the starting zone of both shed 7 East and West. The Shed 7 East avalanche deposited debris approximately 150 meters above Shed 7 and the Shed 7 West avalanche had terminated 2/3 path in the Shed 7 West path proper. Both released on southerly aspects in the upper elevation starting zone.Smaller slab activity was noted in Shed 5 and along the rail grade. No slabs were released artificially. | |
| 2012-01-24 | 17:00:00 | Shed 4D SZ | Steiner | Toured up the Burnout avalanche path and continued up and over to the starting zone of Shed 4D. Conducted full profile in the 4D starting zone and then descended to the Burnout starting zone and conducted a second profile. Ascent conditions were excellent and descent was excellent above1676 m (5,500 feet). From 1676 m to Canyon floor skiing was tricky due to a buried rain crust that is now 10 cm (4 inches) beneath snow surface. Rain crust was added to snowpack last Saturday, 1/21/12. | Air temperatures today averaged -4 C, skies were overcast with no precipitation, and WEST winds were increasing throughout the day. By the end of the day, windloading was active at ridgetop elevations on EAST and NORTHEAST aspects.. | Snow profile conducted on a southeast aspect was full depth at approximately 1768 m (5800 ft) elevation in the starting zone of Shed 4D. Snowpack was 157 cm (62 in) with the upper quarter (1/4) composed of new snow and mixed forms (facets & rounds.) The next quarter of the snowpack consisted of a 15 cm 1F hardness layer atop a sandwich of facets and decomposing crusts. Beneath this, the bottom half (1/2) of the snowpack was comprised of yet more mixed forms/ decomposing crusts and well established depth hoar up to 2mm in size.Stability tests consisted of both ECT and CT. ECT results were all ECTN. CT results were conclusive (CT15 Q2 x 2) on a decomposing crust located 95 cm from the ground or 62 cm from the surface of the profile. | No recent avalanche activity observed. However, widespread, small (D1), low elevation natural activity did occur on 1/21/2012 and entrained recently fallen snow as well as old snow. Some releases extended in depth to the ground. Activity was limited to steep cutbanks/ rock faces. | |
| 2012-01-20 | 09:00:00 | Mount Shields | Steiner | Toured today with Jason Grizwold, District Ranger for Glacier National Park, up the southeastern aspect of Mount Shields to the south ridge of “Little Shields.†Continued on ridgeline to an elevation of 6900 feet elevation. Touring was slow due to trail breaking in up to 60 cm of new low density and wind transported snow. Descended northeast exposure of Little Shields to skier’s right treed ridge… Followed this ridgeline feature to the Fielding Creek Drainage. Skiing conditions on upper third were excellent, middle third satisfactory, and lower third tolerable but slow going as low density snow was covering (hiding) numerous hazardous obstacles. | Temperatures had been warming all night previous to tour and at start of tour air temp at the Canyon floor was -8C (17F) and at high point air T was -4.8 C (23F). Light snow showers throughout the day. Southwest winds gusting moderate to strong… Snow transport onto northeast exposures. | Snow profile conducted on a northeasterly aspect was full depth at approximately 2106 m (6910 ft) elevation on Little Shields. Snowpack was 157 cm (62 in) consisting of mainly new snow and mixed forms in the upper half of snowpack and mixed forms to well developed facets in lower half. Hardness in upper third was Fist, middle third 4F+ and, lower third Fist. In this profile, middle third of snowpack was bridging an otherwise unconsolidated snowpack. Stability tests were limited to Compression Tests with no extraordinary results. CT 13 and a CT12 both Q2 were main focus and found on a decomposing crust layer approximately 55 cm from snowpack surface. This layer was not observed in sidewall profile examination. | No avalanche activity observed. However, low elevation natural activity did occur on 1/19/2012 and was limited to recently fallen new snow on steep cutbanks/ rock faces. On our approach to Little Shields we did have some localized shooting cracks at lower elevations and occasional audible collapsing. Cornice drops onto northeast exposures at approximately 1676 m (5,500 ft) resulted in no slab releases. | |
| 2008-12-22 | 14:40:00 | Shed 4C | Dundas | Toured above the rail throughout the starting zone of Shed 4. Due to the season’s thin snowpack this was our first field day of the 2008-09 season. | Another cool day in the mountains. -16.5 C air temp in the starting zone of shed 4C. Light easterly winds with good visibility. | Thin, weak, and cold! At 5200’ we recorded a 40 cm snow depth with a surface snow temp of -13.1 C and -3.8 C at the bottom of the pack. The lower half of the pack was composed entirely of faceted snow that is F and 4F hard. The upper layers of the pack are comprised of new snow deposited from the past week with a hardness of F and 4F. The 4F surface layer is soft slab formed from the recent easterly winds. No audible failures were heard but short shooting cracks were the norm throughout the entire tour. Compression tests showed failures between the bottom of the new snow layer and the top of the facets with scores of CTE 1, CTE 2 and CTE 3. Easy failures were also initiated by weighting skis throughout the ascent and descent. | No recent avalanche activity observed. |