Northwest Avalanche Center

Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
December 27, 2022
Submitted:
December 27, 2022
Observer:
NWAC Forecaster - Katie Warren
Zone or Region:
East Central
Location:
Salmon La Sac (2400ft - 3100ft, Primarily W aspects)

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced

Media/Attachments

These shiny surfaces are a thick ice crust from freezing rain and sleet. Supportable to skis, but not boots.
These settlement cracks were visible in nearly all steep terrain and likely occurred during the peak precipitation over the weekend.
This extended column test failed and propagated on a layer of buried surface hoar.
Preserved surface hoar buried about 1.5ft deep.
Snow profile from 3100ft on a west aspect in the Salmon La Sac drainage.

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Temperature:
35°F
Wind:
Light

It was a warm day with light rain on and off during the morning. Low clouds and some valley fog prevented any good visuals of the surrounding peaks. Winds were mostly light and variable with some moderate gusts down in this sheltered valley.

Snowpack Observations

A thick (.5-1") supportable freezing rain/sleet crust exists on the surface in most lower-elevation locations. Sticking to low-angle terrain and light turns kept me from breaking through this crust for the most part. However, it was not supportable for walking around in boots. Natural long shooting cracks were visible on many steep terrain features and convexities, now preserved in ice from the freezing rain. These likely occurred during peak precipitation over the weekend.

At 3100ft I found about 3ft of snow. Below the surface crust, the snowpack is saturated to about 5-6" with dry rounding grains below. Down approximately 1.5ft I found a layer of well-preserved SH (12/8) that indicated the potential for propagation in snowpack tests (ECTP 11 Sudden Collapse). Water would pool at the front of my snowpit wall in various layers, indicating that water is moving through the snowpack.

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