Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
February 5, 2022
Submitted:
February 5, 2022
Observer:
NWAC Forecaster - Josh Hirshberg
Zone or Region:
Stevens Pass
Location:
Skyline Ridge (4,060-5,300ft SE-S, NW-NE)

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced

Media/Attachments

A profile from Skyline Ridge, 5280ft, NNW. Notable sudden collapse (CTM SC) and propagating (PST 24/100 END) test results on the late January crust/facet weak layer.
A profile with the layer of most concern- late-January facets sandwiched between two crusts, down 72cm. NNW, 5,280ft, Skyline Ridge
Propagation saw test indicating propagation likely on late January facets, sandwiched between two crusts, down 72cm. PST 24/100cm END. NNW, 5,280ft, Skyline Ridge
Propagation saw test indicating propagation likely on late January facets, sandwiched between two crusts, down 72cm. PST 24/100cm END. NNW, 5,280ft, Skyline Ridge
A tilt test breaks cleanly on a storm interface 30cm below the surface. NNW, 5,280ft, Skyline Ridge
Northwest to west wind overnight plastered new snow to the trees. Skyline Ridge
Light snow and poor visibility at Skyline lake in the morning.
Rollerballs and small wet loose avalanches on a steep east-southeast aspect, 4,400ft. Stevens Pass.
Fresh wind features and small loose wet avalanches (low in the track) in the Berne Chutes. South through southeast, 4,500-6,000ft, Nason Ridge.
Low clouds hang east of Stevens Pass around midday as the sun warms the snow surface on southerly aspects.
Snow surfaces moistened with sun and warm temperatures in the afternoon. Roller balls and tree bombs covered sunny slopes. south aspect, 4500ft

Advanced Information

Weather Summary

Wind:
Calm
New/Recent Snowfall:
10cm in the past 24hrs

Overcast in the AM with light snow and snow level at 3500ft. Becoming few clouds to clear (especially east of Henry creek) by 13:00. Calm near treeline ridges w evidence of overnight wind transport. See photos of wind/snow, overcast skies, clearing by midday, etc.

Many rollerballs with numerous small (D1) wet loose avalanches on steep E-S-W near and below treeline

Snowpack Observations

Surfaces on solars warmed significantly by midday, producing rollerballs.
A quick pit on SE, 4,480ft found moderate, planar hand shears on the Jan 30th interface- a 5cm layer of 1F+ hard melt-forms/rounded facets over the stout late Jan crust.

Profile- 5280ft, NNW
HS 310cm, HN24 13cm, boot pen 50cm
Late Jan FC/crust was surprisingly weak, tho capped w stout crust.
↓59cm- Jan 30th FCsf, capped w soft IFrc- strong and well-bonded. PST 80/100cm END, CTN, ECTX
Layer of concern- ↓72cm, 4F hard, 0.5-1.0mm FCxr. Sandwiched under 5cm of Knife hard Jan 20 crust. CTM (SC), ECTN 40 (beyond bounds of test), PST 24/100cm END
See profile graph and photos

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Persistent Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: Lat Jan crust
Weak Layer(s): Jan 30, 2022 (FCsf)
Comments: Jan 30th FC are rounding and bonding well outside of 4,300-4,700ft. Facets sandwiched under the Jan 20th crust remain very weak on some polar slopes
Wet Loose
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 2/5
Comments: More warming and sun than anticipated. Didn't expect these to be as prevalent as they were. Plenty of snow left for a more full round of activity tomorrow
Wind Slab
Layer Depth/Date: 2/4
Comments: Suspect these are shallow and isolated to specific. Saw visual evidence of shallow drifting overnight (see Berne Chutes photo). Didn't assess directly
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