Date of Observation: 01/23/2021
Zone: Northwest Mountains
Aspect: North, North East, South East, South
Elevation: 10500+
Avalanches: Natural soft slab R2 D1.5 on Cascade south. Looked to start in chute above tree line and run past summer road.
Weather: Gusty west wind and short lived inch an hour rate snow pulses in the morning. Small clearing from noon until 3 followed by light wind and snow.
Snowpack: Generally 40cm new snow on dry spell layer.
Date of Observation: 01/23/2021
Zone: Northwest Mountains
Location: Red Lady skin track
Aspect: East, South East, South
Elevation: 11,300
Avalanches: Intentionaly skier triggered this persistent slab R1.5 above some pretty steep and suspect terrain that no one really skies but is right off the skin track. Quite a stubborn release, but failed at or near the ground. Crown was approx 50 ft wide and well over a meter in places.
There were also three visible R1 storm slabs in the bowl. And one a bit below the aforementioned intentional trigger.
-KH
Weather: Wind gusts above TL easily pushing 45+mph.
Snowpack: Storm snow seemed to average about 30cm but some drifts up to 50cm near TL.
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Date of Observation: 01/23/2021
Zone: Northwest Mountains
Location: Anthracites skin track near the top before your turn right to tree chit or left to 7th bowl
Aspect: North East
Elevation: 11,200
Avalanches: D1 propagated about 50 feet wide
Weather: Actively snowing and windy on the ridge. 20 degrees
Snowpack: Mid storm 15” new snow. 11am Saturday 1/23. Avalanche problem: storm slab
Photos:
Date of Observation: 01/23/2021
Name: Cosmo Langsfeld
Zone: Southeast Mountains
Location: Cement Creek
Elevation: 9250
Weather: 1.5” @ 6:30aa
Date of Observation: 01/21/2021
Name: Ian Havlick
Zone: Southeast Mountains
Location: Redwell to First Bowl Skooks
Aspect: North, East, South East, South, South West, North West
Elevation: 9000-12,500
Avalanches: small D1 dry loose in first bowl Schuykill. Slow moving and avoidable but could get surprised in wrong terrain. Managed problem with avoidance and awareness. Smart re-grouping areas out of fall line.
Weather: Orographic snow showers mostly in AM. 2-3″ new snow accumulation. perfect Stellars, minimal wind except 20mph NW on ridgelines of Emmons. Minimal wind effect on Skook ridgeline. Temperatures moderated throughout day and say some greenhousing softening southerly slopes and surface snow.
Snowpack: Generally faceted with minimal slabs denser than 4F hardness. No formal pits but handpits and pole probing revealed minimal slabs. Travelled terrain with LOW danger in mind and saw no signs of instability. Widespread 1-2″ windboard capping facets in Redwell. Potentially todays stellars temporary weak layer when buried?
Date of Observation: 01/18/2021
Name: Ben Pritchett
Zone: Northwest Mountains
Location: West Elk Wilderness
Aspect: East, South East, South
Elevation: 9,300-11,600′
Weather: Ridgeline Wind Speed: 10-20 mph
Ridgeline Wind Direction: NW
Wind Loading: Light
Temperature: 17 F
Sky Cover: Broken
Depth of New Snow: 1 cm
Depth of Total Snow: 70 cm
Weather Description: Overcast at sunrise turning to partly cloudy by late morning. Brisk winds at ridgetop did not have much snow to move.
Snowpack: On east to southeasterly-facing terrain below and near treeline we found a generally faceted snowpack with an exceptionally weak snow surface. We moved through and over lots of avalanche terrain with no collapsing or shooting cracks. We skirted around the margin of one recently wind-loaded slope just below the ridge crest. In a lower angled part of this slope we found an ECTX 17 (slab fracture), that popped cleanly in a compression test on the Dec 11 interface (top of the large-grained depth hoar below an old melt-freeze crust). This structure would probably not propagate across a slope given the weakening slab, but with additional loading I would anticipate the old Persistent Slab problems will come back to life. Even now, if there was a portion of this slope with a stiffer mid-pack slab I would expect to get different (propagating) results. With a bit of uncertainty, we opted out of center punching the steepest parts of slope. While the chance to trigger might be lower, any avalanche would probably gouge to the ground and grow large South-facing slopes had a well developed sun-crust capping a layer of very weak facets. Not good news once slabs develop on top.
Date of Observation: 01/18/2021
Name: Zach Kinler
Zone: Northwest Mountains
Location: Anthracite Mesa
Aspect: East, South West, West, North West
Elevation: 9,400′-11,000
Avalanches: Observed the previously reported skier-triggered slide in the Purple Palace exit. HS-ASu-R1-D1.5-I
Weather: Lovely in sheltered terrain below treeline with temps around freezing, calm to light breezes. Light to moderate NW wind still pumping in open areas and closer to ridge line.
Snowpack: Mainly looking for soft snow in sheltered west-facing terrain on a quick rec tour. Previous travel in this area revealed HS in the 80-90 cm range before the recent wind event. Today HS was more like 60-70 cm with open areas being mostly scoured revealing past skin/ski tracks. Suttle terrain changes on these cross-loaded aspects created thin, small and very stiff(Pencil hardness) slabs. Avoided steep slopes involving terrain traps where these isolated slabs were found.
Visited the skier-triggered avalanche on the exit from Purple Palace on the way out. This terrain was a steep, East facing open slope where recent winds created a drifted pocket at the top the run. Once triggered, this small slide quickly accelerated downslope entraining mainly surface snow before stacking up deeply at the creek bottom below. Perfect example of how a small and isolated problem becomes magnified by the terrain.
Date of Observation: 01/18/2021
Name: Mark Robbins
Zone: Northwest Mountains
Location: Purple palace exit
Aspect: East
Elevation: 9,750-10,000
Avalanches: Unintentionally triggered a small wind slab at the entrance to the exit slope of purple palace which propagated and entrained most of the season’s snowpack, running with energy through small trees about 300 vertical feet to the creek. Didn’t get an exact read on the depth of the debris pile but may be close to 6 feet. I believe I caught the bottom edge of the slab, the crown is maybe 15 feet above my entrance track. I saw the slab breaking around me and immediately skied traversing to the right to exit the slide.
Extreme moment of complacency not identifying the obviously windloaded pocket and high consequence of the relatively small avalanche problem due to the terrain trap. Low danger rating, minimal feedback earlier in the tour, and being so close to the end of the tour, added to the recipe for complacency. In retrospect the entrance was obviously windloaded and should have been quickly identified as a hazard.
Photos:
Date of Observation: 01/17/2021
Name: Evan Ross
Zone: Northwest Mountains
Aspect: West, North West
Elevation: 10,500-11,200
Snowpack: Traveled through westerly facing terrain features at both BTL and NTL elevations. I’ve been through that area 2 other times in the last couple of weeks. Each time now on a slightly different route. Basically, on 1/6 traveling through that area produced some alarming and far running shooting cracks. On 1/12 there were still some concerning shooting cracks and uninspiring red flags, but a little quieter than back on 1/6. Now today, there was still some nice soft snow in protected areas, but no avalanche concerns due to a heavily faceted snowpack. While the hard slabs we traveled on at both BTL and NTL elevations also didn’t show any signs of instability. Today was the first time I wasn’t concerned about triggering an avalanche in that terrain. Spent a bit of time traveling other aspects, N,E,S… also with no signs to instability.
Date of Observation: 01/16/2021
Name: Chris Martin
Zone: Southeast Mountains
Location: Snodgrass/Gothic Road
Aspect: North, North East, East
Elevation: 9600-10000
Avalanches: D1 Avalanche on East Facing aspect, Hard slab, looks to be 30cm thick, Naturally triggered. Not sure if it released today or prior to today.
Weather: Partly cloudy AM into a blue bay day
Snowpack: Hunting for wind load, found on Easterly slopes BTL in isolated pockets. They began as thin crusts and with some hunting we found 6-12″ hard slabs, Pencil hard. Cracking beneath feet to about 6′ around some of us and one that shot our fairly far, see photos.
No propagating test results, only dug in areas where there was no wind affect and deteriorating slabs existed, did not dig in wind slab.
Depth Hoar at base of pack is growing in size (NOV 6th Layer 3-4mm FC/DH). The Dec 10th FC layer down 45cm is also exhibiting signs of facet growth. Slab above Dec 10th layer F-4F and continuing to deteriorate.
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