Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Matt Primomo
Observation Date:
March 8, 2021
Submitted:
March 8, 2021
Zone or Region:
Stevens Pass
Activity:
Skiing/Snowboarding
Location:
Skyline

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Soft Slab
Size:
Size 1: Relatively harmless to people
Elevation:
6400
Aspect:
NE
Comments:
A few recent natural, small wind slabs out of northeast facing terrain in upper White Pine Cirque, as well as the East bowl of Mt Mastiff.
Photo:

Signs of Unstable Snow

None reported

Observations

I saw wind drifting snow near ridgelines in the area up until about mid-day. Sunny skies in the morning gave way to high clouds by afternoon, and winds decreased.

Steep southeast aspects were beginning to warm, and small loose wet avalanches appeared possible to trigger on steep slopes.

I found 8" of new snow from the past few days, which felt more shallow on southerly aspects because it sat on a more recent sun crust. It wasn't completely bonded to old surfaces on shaded aspects, and I did note some minor cracking around skis. The sun crust from last week is about 10" thick on SE-SW aspects. The February 23 crust is down about 3ft. I found the Mid-January crust down 9ft on an ESE aspect at 5,350ft near Heather Ridge. I spent some time excavating a deep pit, and found mixed results with deep tap tests.
One test failed, sudden planer in faceted melt forms, above an ice lens (DTT26, SP).
Another test failed further below that within the melt-freeze crust complex.
Of note, I couldn't get failure on the .5mm rounding facets above the crust with these tests.

Media

East bowl of Mt Mastiff. East at 6,600ft
Rock Mountain with a glide crack below treeline, and older deep slab avalanches up higher.
Monte Cristo and Kyes Peak from afar. Deep slab avalanches from last week or older in many areas.
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