Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
December 18, 2022
Submitted:
December 18, 2022
Observer:
NWAC Forecaster - Irene Henninger
Zone or Region:
Stevens Pass
Location:
Skyline (4000-5000ft, N, S)

Signs of Unstable Snow

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

Media/Attachments

We dug just below Skyline Ridge. A layer of surface hoar was visible beneath the new snow layer. The old crust/facet layers were still noticeable at the bottom of the pit.
Buried surface hoar beneath the new snow layer.
2mm rounding facets beneath the 11/22 crust. They were 1Finger hardness.
I did 2 deep tap tests on the rounding facets beneath the 11/22 crust. In one test the layer failed at 24 taps, the other test didn't get a result.
12/8 buried surface hoar layer only stood out during this one test. Another CT produced no result, and it did not break on a tilt test. The line was just barely visible in the pit wall.
In the 1/2hr we were in the pit this much snow piled up on the skis. This was when occasional moderate variable direction wind gusts began passing through as well.
South facing crust beneath the new storm snow at 4500 feet.

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Temperature:
22°F
Wind:
Light
New/Recent Snowfall:
5cm

We were mostly in sheltered terrain, but occasional moderate gusts of wind passed through while on the ridge. Brief patches of blue skies were seen, but it was mostly snowing in variable bursts during our morning tour. up to a rate of more than a cm an hour (s1). The new snow was very low density.

Snowpack Observations

Northerly aspects: 4500-5000ft: We found a mainly right side up snowpack. Ski pen was approx 20cm. Nice dry powder. Sluffing only occurred in very steep areas in the top 1cm or so of snow. There was buried surface hoar beneath the new snow, which was not deep enough when we were out there to pose a problem. Other layers that stood out in a pit were the 12/8 buried surface hoar layer, found about 35cm down but was barely discernable. Got one CTH on that layer, which was not repeatable. The mixed forms (rounding facets) beneath the 11/22 crust produced a hard deep tap test result, but again, was unrepeatable.

South-facing aspects: A 1cm crust (give or take, depending on how south-facing you were) was present beneath the new snow layer. The 50cm beneath that progressed in hardness and we found no weaknesses where we were.

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