Observation: NWAC Forecaster
Basic Information
Observation Details
Observation Date:
December 8, 2021Submitted:
December 8, 2021Observer:
NWAC Forecaster - Matt PrimomoZone or Region:
Stevens PassLocation:
Stevens Pass (West, North and East aspects up to 5,300ft)Signs of Unstable Snow
Recent Avalanches?
None ObservedCracking?
IsolatedCollapsing?
None ExperiencedMedia/Attachments
Advanced Information
Weather Summary
Cloud Cover:
OvercastWind:
Strong , WNew/Recent Snowfall:
3-6"We experienced a rapid temperature drop in the morning as heavier snowfall gave way to moderate snow, then showery by noon. Very strong winds were actively drifting snow even in some areas below treeline. Obscured skies turned to overcast and some patches of blue by noon.
I was able to easily trigger a very small wind slab, maybe 15ft wide x 1ft deep that sluggishly slid downhill for a short ways. This slid within the new snow, a few inches above last night's thin freezing rain crust.
Snowpack Observations
We found 3-6" of new snow on a thin, translucent freezing rain crust from last night. This sits over moist to dry snow with a noticeable layer boundary at the late November crust. HS ranges from 16"-28" in the area, deeper in wind drifted locations. At a profile site on a W aspect at 5,000ft we observed slightly weaker snow just above the late November crust, but this layer was unreactive to tests. At higher elevations, this interface could harbor weaker snow.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Wind Slab
|
|
Layer Depth/Date: 6-14" |