Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
February 21, 2021
Submitted:
February 22, 2021
Observer:
SAC - VandenBos
Zone or Region:
Sawtooth and Western Smoky Mtns
Location:
Shaw, near Dollarhide Summit (6,500-9,000', N-NE-E-SE-S)

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced
Unsure of timing on avalanche near Dollarhide Summit, but the debris appeared fairly fresh from a distance.

Bottom Line

Unstable snowpack test scores and recent avalanche activity point to the continued potential of avalanches failing on buried weak layers in this area.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Wind:
Moderate , W

Moderate westerly winds with strong gusts. Occasional S-1 flurries with no accumulation.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Feb 19, 2021
(+/- 3 days)
Shaw
SE 8900ft
D2 I-New/Old Interface 3ft N-Natural Report
Shaw

Snowpack Observations

Primary goal was to look at character and presence of 1/27 and 12/11 interfaces in both solar and shaded terrain. In solar terrain, 1/27 interface (or what appeared to be 1/27) was 40-50cm down and presented as a 3-4cm thick MFcr with 1-2mm FC on top. This interface yielded repeated propagating results in ECTs with hard force. On shaded aspects, 1/27 was not distinct. Here, the entire upper portion of the snow was relatively well bonded and gave only very rough shears. 12/11 interface yielded ECTPs with hard force on both shaded and solar aspects. This was particularly impressive on shaded aspect, given the slab thickness of 1+m.

Two snowpits near Dollarhide Summit

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: down 40-50cm
Weak Layer(s): Jan 27, 2021 (FCsf)
Comments: Rose colored based on where I directly observed the problem
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: down 70-110cm
Weak Layer(s): Dec 11, 2020 (FCsf)
Comments: Rose colored based on where I directly observed the problem