Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
January 4, 2021
Submitted:
January 5, 2021
Observer:
SAC - VandenBos, Creelman
Zone or Region:
Galena Summit and Eastern Mtns
Location:
Mushroom Ridge (7,600-9,300', primarily southern half of the compass)

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
Isolated
Collapsing and cracking isolated to untraveled terrain, which there isn't much of. That said, everywhere we went that didn't have sign of earlier passage produced cracks and slope collapses that propagated out to the end of sight. I'm pretty confident we would have seen widespread collapsing in untraveled terrain.

Snow Stability

Stability Rating: 
Poor
Confidence in Rating: 
High
Stability Trend: 
Worsening

Bottom Line

Storm arrived later than forecast, but was producing significant moisture by early afternoon. Even with a small load stability decreased rapidly. Based on weather station data, stability continued to decrease later in the evening and overnight.

Advanced Information

Weather Summary

Cloud Cover:
Obscured
Wind:
Light , SW
New/Recent Snowfall:
15cm new snow by nightfall

Snowing S2 through duration of tour. Winds audible aloft and blowing plenty of snow at highway level on the drive south from Stanley. Light winds blowing along ridge.

Avalanche Observations

None observed, zero visibility.

Snowpack Observations

Slab on top of 12/11 facets is 45-50cm thick in this area. The entirety of the slab is in the 4F- to F- range. Very soft slab was propagating fractures despite this.

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 45-50cm
Weak Layer(s): Dec 11, 2020 (FCsf)

Terrain Use

We avoided avalanche terrain.