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Missoula Avalanche

Professional Observation

Basic Information

Observation Details

Observation Date:
January 21, 2022
Submitted:
January 22, 2022
Observer:
WCMAC - George D'Angelo
Zone or Region:
Central Bitterroots
Location:
Central Bitterroots

Signs of Unstable Snow

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

Snow Stability

Stability Rating: 
Good
Confidence in Rating: 
High
Stability Trend: 
Steady

Bottom Line


We found a generally right-side-up snowpack with small wind slabs at treeline and above in specific areas in the Central Bitterroots. There was crusty and moist snow below about 6000ft. From 6000 to 7500ft 2 breakable crusts, a thin crust an inch down and a more substantial one 6 in down. The crusts got less noticeable as we climbed in elevation, and there's about 1-6" of new snow on the top . Above 7500 feet there was about 6-8" of new snow with no noticeable crusts below, which made for good riding in less wind-affected areas.

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Temperature:
28F
Wind:
Light , W

We saw evidence of light blowing snow but little evidence of windslab formation below treeline. Temps were cooler today and are forecast to warm over the weekend.

Snowpack Observations

We dug two pits around 8000ft on both SE and NE aspects. We found evidence of a weak layer of decomposing fragments of old stellar dendrites about 2mm in size about 1ft below the surface in both pits. Our results from our Extended Column Tests did not indicate propagation of a fracture to be likely in this layer. Future settlement of the upper pack with warmer temperatures could make this layer more reactive over the weekend.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wind Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
Layer Depth/Date: 8-18"
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