Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
December 22, 2019
Submitted:
December 23, 2019
Observer:
SAC - VandenBos
Zone or Region:
Sawtooth and Western Smoky Mtns
Location:
Fishhook to Profile

Signs of Unstable Snow

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.

Snow Stability

Stability Rating: 
Fair
Confidence in Rating: 
Stability Trend: 
Steady

Bottom Line

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

Weather Summary

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.

Avalanche Observations

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.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Persistent Slab
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
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