Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
March 17, 2023
Submitted:
March 17, 2023
Observer:
NWAC Forecaster - Matt Primomo
Zone or Region:
Stevens Pass
Location:
Loch Eileen (NW-SE 2,000-6,100)

Signs of Unstable Snow

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

Media/Attachments

A snow pillow on a boulder showed the snowpack structure reasonably well. Valentines day Crust was weak with much weaker snow beneath it, all the way to the line which is the MLK Crust. 5,200ft
The top of this is stiffer wind packed snow, with light emitting through the weaker snow beneath the Valentines Day Crust. MLK Crust is the thin clear ice lens below.
Looking up towards Lake Donald.
Cornices and couloirs above Loch Eileen.
Ice at the outflow of Lake Donald. Small loose slide to the right demonstrating moistening snow.
Plenty of wind affect near ridgelines.
Nice settled powder in the shade on supported slopes.
Velvety surfaces in the shade.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Sunny
Wind:
Light , SE

Temperatures were cool in the morning and it felt wintry, though by mid day it felt like spring. No new transport observed. Winds were light.

Small loose wet slides from steep E-S facing slopes by mid-day.

Snowpack Observations

Technically Stevens Pass, but also started in the East Central...We traveled up to Loch Eileen and above it on a nice rib that splits the lake with lake Donald. There had been plenty of wind drifting with textures and slabs in the NTL and ATL. Traveled up to 6,100ft and found nice soft dry snow in the shade, though anything facing east was warming and became manky by noon. On our way down, we saw some folks at Alpine Lakes High Camp enjoying the warm sun outside the cabins.
Slopes in the shade stayed dry, and skiied well with velvety mid sized surface hoar. Ski pen was about 25cm.

Structure: General HS was about 200cm, with about 100cm over the Valentines Day Crust and 125cm to the MLK Crust. Im sure these depths vary widely as you get up into the wind zone with very thick drifts and areas where it could be quite thin.

I could feel weak snow beneath the Valentines Day Crust fairly easily with a probe on a number of different slopes. Digging down, 1mm rounded facets mixed with decomposed crusts down to the stouter and smoother MLK crust, essentially creating a thick weak layer. Hardness was 4F+ beneath the Valentines Crust but became 1F above the MLK. Compression Tests yielded Sudden Collapse results surrounding both crusts (CTM SC down 100cm, and CTH SC down 125cm on the MLK Crust.) See profile photo.

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