Date of Observation: 02/02/2021
Name: Zach Guy

Zone: Northwest Mountains
Location: East Beckwith
Aspect: North East
Elevation: 9900-11500′

Avalanches: Noteworthy cycle of persistent slabs on the west side of the Ruby Range (W and SW aspects N/ATL). See photos. Many of these likely ran on Sunday triggered by wet loose slides or simply warming. The others ran mid storm on Saturday. These slides are important because they are the first persistent slab avalanches we’ve observed on these windward aspects since the new year.
In our travels today, the only steep slope we approached collapsed, cracked wall to wall, but didn’t slide. Small, unsupported rollovers were easy to trigger, soft slabs breaking on 1/19 interface, 18″ deep or so.
Weather: Creepy warm. Noticeably warmer on the west side of Kebler Pass. Mostly cloudy skies until clearing late afternoon.
Snowpack: Widespread collapsing below treeline, with some shooting cracks and collapses radiating over 200 feet across slopes. Emerging to near treeline, slabs are thicker and more stubborn. We didn’t get signs of instability underfoot near treeline, but tests produced consistent moderate propagating results down 2 to 3 feet under 1F slabs.
Snow surfaces were moist to 10,400′ on northerly aspects. Below treeline, the super soft slabs of earlier this week are now stiffer and capable of propagating further, thanks to settlement the last few days.
Snow surfaces going into the storm on north-facing terrain: Fist hard DF’s near and above treeline, not an alarming layer. Below treeline, and somewhat unique to our snowpack climate, we saw melt-layer recrystallization occurring at the end of the day (see photo), the result of warm, cloudy conditions melting the snow surface this afternoon and then abruptly changing to clear skies with good radiative cooling on the surface. Dry, small-grained facets over a soft meltfreeze crust exist below 10,400′ on the surface of shady aspects here. There were also isolated areas of surface hoar that got cooked off by the end of the day below treeline.

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Date of Observation: 02/01/2021
Name: Zach Kinler Eric Murrow
Zone: Northwest Mountains
Location: Elk Creek

Aspect: North East, East

Elevation: 9,600-10,500

Avalanches: Remotely triggered two avalanches from ridge top. The first was from ~250 feet away while moving towards the top of a steep open slope, D1.5 with debris piling up deeply in the terrain traps below. The second was triggered while traversing the flats above a steep open slope. This avalanche was a D2 that ran 200+ feet.
Observed 1 small storm slab on a North aspect BTL as well as a D1.5 Persistent slab on a SE aspect BTL. Both likely ran Saturday.
Photos of previously reported avalanches from Sunday 1/31 in Elk Basin on near treeline southeast slopes.

Weather: High clouds drifted in making a warm day feel a bit cooler. High temps were at or just above freezing with calm winds.

Snowpack: The snowpack did the talking for us on this tour. We got a booming collapse as soon as we gained the ridge and while this lower angle slope did not run, it was obvious that conditions were right to produce an avalanche. The next couple steep, suspect slopes held strong as we stomped from the ridge and it wasn’t until we started moving towards the next slope that we got a faint collapse in the flats around a few trees about 250 feet from the top of the path and released the first of two remote triggers. This slope had little to no drifting, failing at the 1/19 interface down 47 cm. F-1F slab resting on F hard, large-grained near-surface facets(ECTP15 just above crown). We decided to continue up to one more path in order to gain a bit more information. After traversing across the top and moving from a weak and unsupported structure onto a drifted portion of the slab, we were able to get a collapse and remote trigger a D2 failing at the same interface down 55 cm in this drifted start zone(ECTP13 at the crown). Overall HS in this area has nearly doubled since 1/19 and averaged 120 cm.

Date of Observation: 02/01/2021
Name: Zach Guy

Zone: Northwest Mountains
Location: Irwin Upper Upper Westwall
Aspect: West
Elevation: N/ATL

Avalanches: Nothing new since the slides reported yesterday.
Weather: High thin clouds increased in thickness through the day. Mild temps. Light winds.
Snowpack: Explosive testing on upper elevation west-facing terrain with relatively minimal snow safety work this season. No results. Probing revealed discontinuous and isolated persistent slab structures across the terrain, due to previous wind erosion. Anything with a hint of south had a thin, melt freeze crust on the surface after yesterday’s warmup. Crusts did not soften today. Measured 1.6” Storm SWE in a relatively sheltered near treeline slope.

Date of Observation: 01/31/2021
Name: Ben Pritchett

Zone: Northwest Mountains
Location: Views in around the West Elks, Ruby Range, and Elk Range.

Avalanches: Lots of avalanche activity up-valley from Crested Butte. Kebler Pass, Ruby Range, and the main Elk Mountains all went through a cycle of mostly D2 avalanches. East to southeast near and below treeline had the most number of avalanches. Many of these avalanches near and below treeline broke broadly, and generally deeper in the snowpack, failing on buried persistent weak layers. Some of these released as late in the day as 3:30pm on east-facing terrain. Above treeline many slides released in the storm snow earlier in the loading event (January 30) on north through northeast to east-facing slopes. These had softer, lightly filled in crowns and were mostly small relative to the paths though some were D2’s in destructive size.

Photos:

Date of Observation: 01/31/2021
Name: Evan Ross

Zone: Northwest Mountains
Location: Kebler Pass

Avalanches: Widespread natural avalanche cycle, primarily on E to SE to S facing slopes at all elevations. Could easily count up 20 to 30 avalanches, but probably more. Elk Basin had 4 or 5 D2’s. Numerous large slab avalanches in the Ruby/Owen/Purple group. Numerous natural small to large slab avalanches in the NTL/BTL elevations below Ruby/Owen/Purple. The Dyke area had plenty of large slab avalanche carnage at all elevations. Some old crowns from yesterday, and plenty of sharp fresh crowns from early this morning or today. We were not planing in much for avalanche terrain, but still remote triggered at least one 2ft deep slab avalanche. Saw several other human triggered slab avalanches as well, all failing 1.5 to 3 feet deep.

My camera failed today, sadly. So this is really just a quick ob to document that the avalanche cycle reported in other drainages, also occurred in the Kebler Pass Area.

Date of Observation: 01/31/2021

Zone: Northwest Mountains
Location: Robinson Basin
Aspect: East, South East
Elevation: NTL

Avalanches: See photos of large natural persistent slab avalanches on E/SE aspects of Robinson Basin that ran today

Photos:

Date of Observation: 01/31/2021
Name: Zach Kinler, Jared Berman
Zone: Northwest Mountains
Location: Purple Ridge

Aspect: North East, East, South East, South, South West, West

Elevation: 9,600′-11,800′

Avalanches: In addition to the many large persistent slab and wet loose snow avalanches already reported, we observed several wet loose on aspects from SE-S-W in the D1-D1.5 size range. All initiating from steep and often rocky areas near and above treeline midday. Of note was a large persistent slab avalanche and several small persistent slabs that ran midday on Schuylkill Ridge, closer to the peak on a near treeline terrain feature that wraps just south of East in aspect. Looks to have initiated from smaller wet loose snow avalanches as temps warmed.

Weather: Cold start with valleys near or below zero. Temps warmed quickly with abundant sunshine and 11K highs climbing above freezing. Strong solar with no wind, even on ridge top. One of the calmest days I can remember.

Snowpack: HST at valley bottom around 11 inches with up to 16 inches around 11K. HS in this area was 130 cm around 10,500′ and 150 cm and greater moving above 11K. No cracking or collapsing was observed in sheltered areas and a snowpit on East at 10,600′ revealed hard propagating results x1 and non-propagating results x1 on the 1/19 interface. The 12/10 interface was about 100 cm deep and showing signs of rounding but still weak at 4F hard(ECTX). Minimal obs from drifted slopes as we avoided those. Recent snow was warming rapidly on aspects from SE-S-W with moist snow on the surface. East aspects had settled into creamy pow with generally dry surfaces.

Date of Observation: 01/31/2021
Name: Zach Guy

Zone: Northwest Mountains
Location: Baxter Basin
Elevation: 9,600 – 11,700 ft

Avalanches: Numerous natural D2 to D3 persistent slabs ran yesterday or today, mostly above treeline, appeared to be all on 1/19 interface, 3 to 6 feet deep. See photos/captions for details.
Handful of smaller windslabs D1 to D2 ran yesterday, near and above treeline. No natural wind slabs today.
Active loose avalanches throughout the day on the southern and eastern halves of the rose, all elevations, starting as dry loose and evolving to moist or wet loose by end of day. Mostly D1-D1.5 and a couple of D2. Countless small loose dry ran yesterday.
Weather: Unseasonably warm on sunny slopes. Clear skies. Calm winds
Snowpack: 15″ of settled new snow at basin bottom, about 20″ at upper elevations. The 1/19 facet layer is down 4 feet deep below treeline. No shooting cracks or collapses underfoot, but we mostly traveled on a skin track that someone else put in this morning. Rollerballs, ongoing natural avalanche activity (both sluffs and slabs), and rapid warming of the upper snowpack on sunny aspects were all glaring signs of instability to stick to mellow terrain and give runouts a wide berth, which we did. Trailhead was the most crowded I’ve ever seen, but glad to see conservative terrain choices and simple terrain selection by users today.

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