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.

Photos:

Date of Observation: 01/31/2021
Name: Sam Eller

Zone: Northwest Mountains
Location: Elkton Hills
Aspect: East, South East, South, South West, West
Elevation: 11,200

Avalanches: Large persistent slab avalanches off Belleview mountain. Small wind slabs stepped down to deeper layers as the sun warmed those solar aspects. Possible glide avalanche in the paradise basin. Lots of point release on any exposed rock in the afternoon.
Weather: Warm and bluebird.
Snowpack: Creamy, hot pow.

Photos:

Date of Observation: 01/31/2021
Name: Brett Henderson

Zone: Northwest Mountains
Location: East side of Mt. Bellview
Aspect: East

Avalanches: Also saw multiple avalanches on the north side of Gothic

Photos:

Date of Observation: 01/31/2021

Zone: Northwest Mountains
Location:
Aspect: South West, West
Elevation: 10500-11500

Avalanches: Observed several slides on Mineral Point and ridge between Augusta and Richmond. Both appeared to occur during the storm and did not step down into older layers
Weather: Calm and warm
Snowpack: No signs of instability during our tour.

Photos:

Date of Observation: 01/31/2021

Zone: Northwest Mountains
Location: Kebler Pass BTL
Aspect: North East
Elevation: 10,500

Avalanches: Skier triggered R4 D1.5. Released near the top of the slope in the middle of the convexity and propagated across most of the face.
Weather: Sunny and clear skies. Around 10am.
Snowpack: My best guess is it was storm slab that failed on the mid January facet layer. The debris was still fairly soft but deep enough to catch and bury a skier.

Photos:

Date of Observation: 01/30/2021

Zone: Northwest Mountains

Avalanches: Remotely triggered 5 large persistent slab avalanches while ascending a ridge near treeline. Super sensitive. Deepest crown was about 6 feet deep. They all stepped at least in part through last week’s snow. Ran with substantial energy and large powder clouds.

CBAC note: We gathered this observation from a social media post. Details are forthcoming.

Photos:

Date of Observation: 01/30/2021
Name: Irwin Guides

Zone: Northwest Mountains
Location: Irwin Tenure

Avalanches: Touchy storm slabs in the AM chilled out by mid-day and we were able to resume ski checks that produced little beyond moving loose snow and some pocket slabs. Wind slab was not an issue near and btl.
Weather: 15″ storm total at the plot with .8″ of water. Higher elevations have 20-30″ of new snow. Overnight total came in at 6% and today’s snow weighed in at 4.5%. Blower country. Snowing S2 when we departed.

Date of Observation: 01/30/2021
Name: Steve Banks

Zone: Northwest Mountains
Location: Anthracite Range
Aspect: North West
Elevation: 9,800-11,000

Avalanches: No new avalanches observed. Poor vis ATL limited obs.
Weather: Snowing this morning (S2) and tapering through the middle of the day. Couple well timed sunny breaks. Temps in the 20’s and minimal winds. Snow came back after 4 pm with overnight snowfall 4-6” and 1-2” through the day.
Snowpack: Still weak! Average snowpack depth (HS) 135 cm and a ski pole easily passed through all of it. There is a 4F-4F+ slab over the January dry spell facet layer. Multiple collapses and cracks on slopes up to 35* though no releases. Some cracks went all the way to the November weak layer.