Date of Observation: 03/19/2021
Name: Jack Caprio
Zone: Crested Butte Backcountry
The doughnut hole effect showed up in full force this week. Irwin received 20+ inches and areas closer to town only 4 inches. Click here to see how this storm impacted avalanche conditions throughout the zone.
Date of Observation: 03/18/2021
Name: Zach Guy and Zach Kinler
Zone: Northwest Mountains
Location: Schuylkill Ridge
Aspect: North, North East, East
Elevation: 9,000 to 11,400′
Avalanches: Widespread cycle of small wet loose avalanches today above treeline in the Ruby Range (~40 avalanches), generally D1 in size. We had good views of abundant activity on east through south aspects, limited views of westerly aspects. There were fewer slides that initiated near treeline and only a few slides closer to town on peaks like Gothic and Mt. Emmons. Did not observe any slides below treeline.
One small wet loose triggered a large persistent slab on an east aspect near treeline of Schuylkill Ridge today around noon.
Weather: Few clouds, calm winds, spring-like temps.
Snowpack: Today’s goal was to target persistent slab structures on paths that ran in February on northerly aspects. We sampled the upper flanks of a couple of paths, one that ran in early February and the other that ran in mid-February. Despite a lack of signs of instability and non-propagating failures in multiple test locations, the structures on old bed surfaces don’t inspire a whole lot of confidence. Slabs are generally 40 to 45 cm thick (F to 4F) over Fist hard, 1.5-2.0 mm facets. Instabilities seem fairly isolated for the time being on the slopes we tested, but I would expect that to change with additional loading.
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Date of Observation: 03/17/2021
Name: Morgan Boyles
Zone: Southeast Mountains
Location: Above Friends Hut
Aspect: South West
Elevation: 12,000′
Avalanches: Triggered a SS-ASu-R3-D1.5 on 3/17/21 on a small SW slope at 12k above the Friends Hut. Crown was 4″-8″ and the slide propagated the whole 200′ width of the feature. This ran on the crust buried on 3/10. Several other naturals from the last two to three days observed running below rocks on S, W, and E aspects mostly D1 in size. The largest was almost D2 in size and on a steep W facing slope of Star Peak on the Aspen side of Pearl Pass. Some other small loose wet observed.
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Date of Observation: 03/18/2021
Zone: Northwest Mountains
Location: Wang Chung Face
Aspect: North
Elevation: NTL
Avalanches: Skier triggered shallow slab avalanche, ran to the bottom of the terrain feature on Wang Chung. Traversed off of it and wasn’t caught.
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Date of Observation: 03/17/2021
Zone: Southeast Mountains
Location: Carbon Peak North Bowl
Aspect: North
Elevation: 11,200
Avalanches: While making initial turns into the N Bowl on Carbon Peak, I triggered large shooting cracks that propagated 15+ meters on either side of me. After the slope fractured, the slab did not slide on a mid 30-degree slope. I was able to climb out of the start zone and we descended through low angled terrain.
Weather:
Snowpack: Throughout the day we had skied NE and SW facing terrain on Axtell without notable signs of instability. On a N aspect of Carbon Peak @ 11,200 feet, we did not find an obvious crust layer at the 3/10 interface. Snowpack tests resulted in an ECTN 26, and a CTH 25 RP, both failing in the upper snowpack. Based on the characteristics of the fracture (it appeared very deep) and the lack of instability in the upper snowpack, it seems like I may have found a trigger for one of the deeper layers in our snowpack. In retrospect, our slope of choice was perhaps a predictable location for impacting deeper weak layers.
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Date of Observation: 03/17/2021
Name: Zach Guy
Zone: Northwest Mountains
Location: Upper Slate
Aspect: East, South
Elevation: BTL
Avalanches: A handful of small loose avalanches entraining the top few inches of moist snow ran this morning on southerly and easterly aspects before clouds filled in.
Ski triggered a thin wind slab on a south-facing test slope where northerly winds were drifting snow.
Weather: Clear this morning, clouds increased by midday with a few light snow showers. Light to moderate downvalley (northerly) winds at low elevations.
Snowpack: Quick tour BTL sampling storm snow totals to check on how large wet loose activity will be the next few days. In Poverty Gulch, there’s about 6″ to 12″ of settled storm snow, depending on wind effect. At Pittsburg and further down valley, only 2″ or less. The snow surface was moist from solar and greenhouse warming.
Quick pit on an east/northeast aspect BTL in Poverty Gulch produced unreactive pit results on the March weak layers, about a foot deep. The facets here have a bit of vertical separation from the crust, making for a less-distinct interface than what we’ve observed at other locations.
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Date of Observation: 03/17/2021
Name: Erin Sanborn
Zone: Southeast Mountains
Location: ENE aspect of Wolverine Basin
Aspect: North East
Elevation: 11,400
Avalanches: Skier triggered shallow soft slab (crown approx 6″) around 11:45 AM. Relatively wide crown (see photo – not sure on scale, circle on photo is where the skier dropped in); slough stopped approx 2/3 down the aspect. Skier able to ski out of the moving snow. It appeared that another slab on skier’s right was also triggered; possible remote trigger further skier’s left under a cornice (the party of 4 was not certain if the latter slide noted was there at start of ski – unable to determine from above cornice, but worth noting). Second photo shows smaller slab that was likely triggered remotely. This was the first skier to descend, making some of the observations from above difficult to determine.
Weather: Mid-20s; partly sunny; morning wind when skiing up Red Lady, but not wind at the time of the event.
Snowpack: One very small roller noted on the aspect that was skied. We noticed what appeared to be a natural wet slide was noted in Red Well basin on the east facing aspect earlier in the morning.
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Date of Observation: 03/16/2021
Name: Eric Murrow
Zone: Southeast Mountains
Location: Cement Creek to Upper Taylor
Aspect:
Elevation: 9,000′ – 12,100′
Avalanches: Observed two small slab avalanches on northeast (Hunter Hill) and east (Star Pass) alpine features.
Weather: Mostly cloudy skies with a few periods of sunshine. Winds were light even above treeline in typically windy places, no transport observed. New snow accumulation up to 1.5″ overnight with a few short bursts of S1 during the day.
Snowpack: Recreational snowmobile day so made few snowpack obs, only digging was to free my snowmobile. I did measure new snow accumulations since Saturday at the head of Cement Creek at 11,400′ and found 11″ with 1.1″SWE. Snow volumes tapered very quickly as you headed down the valley with just 7 inches near Hunter Creek and only 3 inches at the Cement Creek TH. Below treeline slopes facing east through south through west developed a soft melt/freeze crust on Monday with a dusting to 1.5″ new sitting above. Northeast through southeast slopes near treeline appeared well drifted from the weekend; above treeline loading was a bit more variable depending on the local terrain shape.
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Date of Observation: 03/16/2021
Name: Evan Ross
Zone: Northwest Mountains
Location: Kebler Pass
Aspect: North East, East, South East, South
Elevation: 9,000-11,500ft
Avalanches: A few small sluffs on the south side of Ruby.
Weather: Mostly cloudy with just enough snow and heat to thicken the new snow. About 3″ of snow had accumulated this since early AM. Calm Wind.
Snowpack: Primarily traveled on easterly slopes between 10,500ft and 11,500ft. In these areas, the 3/10 interface was down 40 to 50 cm’s on average, below mostly F hard snow and a couple of other thin crusts. That interface has been well documented and consisted of two crusts with weak snow between. The thin layer of snow between those crusts is notably soft, 1 mm faceted grains. Those faceted grains did have some soft and slightly rounded edges to them.
Dug a test pit on a 28-degree east aspect at 11,400ft. ECT tests were a bit inconclusive. 2 hard ECT N’s, with an additional loading step in one test that finished the propagation through the weak snow between the crusts. Of other note, the only way to isolate a column of snow without cracking and breaking sections of the crust was with a sharp cord on all sides of the column. A shovel blade was to coarse and broke notable sections of the crust when used to clean snowpit walls.
Snowmobile slammed a whole lot of test slopes with no results. Traveled very near several bigger terrain features with no remote triggered results. Despite the lack of red flags or signs of instability, the snowpack structure still appeared concerning and will take time to earn my trust.
Date of Observation: 03/15/2021
Name: Jacob Dalbey
Zone: Northwest Mountains
Location: Redwell Basin
Aspect: North, North East, North West
Elevation: 11,100’
Avalanches: Small (D1) skier triggered storm slab on NW/W aspect btl. Crown approx 10-12”. Failed on a crust as two ski tracks on more northerly aspect directly adjacent to slide produced no activity.
Weather: Cold. Snowy in the morning with patches of blue sky popping through. Mostly clear midday and warm in the sun. Snow was rapidly settling when touched by the sun. Overcast and snowy mid afternoon on exit
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