Professional Observation

Basic Information

Observation Date:

December 22, 2019

Submitted:

December 23, 2019

Observer:

SAC - VandenBos

Zone or Region:

Sawtooth and Western Smoky Mtns

Location:

Fishhook to Profile

Recent Avalanches?

None Observed

Cracking?

Isolated

Collapsing?

None Experienced

Isolated cracking appeared to be originating at the depth hoar above the ground, not on the surface hoar, but hard to be certain.

Stability Rating:

Fair

Confidence in Rating:

Stability Trend:

Steady

Surface hoar preserved here, but less reactive than observed in many other locations. Less open space associated with the surface hoar, appeared that the weight of the overlying slab was beginning to allow SH grains to penetrate the snow above. Still getting short critical cut lengths on PST (mid 30s), but no initiating fractures in ECT and producing dirty shears during informal tests.

Advanced Information

Cloud Cover:

Mostly Cloudy

Temperature:

mid 20's (estimated)

Wind:

Moderate , SW

4-5cm new snow from previous storm up above ~8,000', very little new snow down low. Variable cloud cover, upper-level stratus slowly clearing from the north during the day.

Evidence of some significant activity from previous storm (10 days ago), but its been long enough that it is impossible to tell what culprit weak layer was. My guess, based on previous trip here and snowpack test results that these slides may have failed on DH, but hard to say with any certainty. Several large slides in the alpine around Profile Lake, breaking hundreds of feet wide, depositing debris on the lake, mostly occurring on N-E aspects.

Problem	Location	Distribution	Sensitivity	Size	Comments
Persistent Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Layer Depth/Date: 11/26, down 50-60cm
Persistent Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Layer Depth/Date: 12/7, down 40-50cm