Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
February 23, 2020
Submitted:
February 24, 2020
Observer:
SAC - VandenBos (off duty)
Zone or Region:
Sawtooth and Western Smoky Mtns
Location:
Fishhook Drainage

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
None Experienced
Isolated cracking in thin, freshly deposited drifts where they rested on crust+facet combinations

Snow Stability

Stability Rating: 
Good
Confidence in Rating: 
Moderate
Stability Trend: 
Worsening

Bottom Line

Increasing wind speeds in morning were transporting snow/facets left over from last weekend's storm. Slabs were very thin and isolated.

Media/Attachments

Increasing wind speeds were able to transport faceted snow that developed in the cold, clear weather last week. This photo was taken Sunday (2/23) afternoon before 2-4" of additional snow fell in this zone.

Advanced Information

Weather Summary

Cloud cover and wind speeds increased in the morning, with overcast skies by 10 AM and moderate westerly winds with periodic strong gusts. Sputtery bouts of precip (rimed stellars and graupel) observed in late morning and early afternoon, with <1cm accumulation by 3 PM. Period of partly cloudy skies between 3 and 430, before another band of moisture moved in, bringing flurries of precip, with rates up to S2. 2cm of accumulation by nightfall.

Avalanche Observations

Aside from frequent spindrifting in steep terrain, no new avalanche activity observed. Observed debris from quite a few wet loose/solar-initiated dry loose slides, none greater than D1.5

Snowpack Observations

Direct observations limited to upper snowpack. S-SW quarter of the compass had 2cm thick, ski-supportable crust with a fine band of facets on top on slopes greater than about 30 degrees. Solar margins (SE and W) had a thinner crust, with a layer of facets up to 1cm thick. On shaded aspects, snow from last weekend's storm was faceted down to firmer surfaces underneath. Solar margins and shaded aspects that were firm during the cold weather this past week are likely to be the sweet spots for activity, but given a rapid enough load, icy crusts on direct solars might be touchy in the short term.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wind Slab
Isolated
Specific
Widespread
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5