Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
December 18, 2019
Submitted:
December 19, 2019
Observer:
SAC - VandenBos (off duty)
Zone or Region:
Galena Summit and Eastern Mtns
Location:
Eagle Creek

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
Isolated
Isolated cracking and very localized collapsing in exposed terrain where aging wind drifts rested on a firm surface underneath.

Snow Stability

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

Bottom Line

Slab is faceting and loosing its integrity so obvious signs of instability are decreasing. However, I'm not taking this is an indicator that our weak layers are healing, just waiting for a load.

Advanced Information

Weather Summary

Temperature:
inverted
Wind:
Moderate , SW

Pretty steady moderate SW wind up high, but had to get way up (~10,000') to get into it. High stratus opened up a bit to the west for a few hours in the afternoon. Inversion mixed out by the end of the tour. Start around noon in a puffy, summit at 2:30 in a t-shirt.

Avalanche Observations

No recent avalanches observed. Limited time prevented a thorough glassing. Elk made a good effort to trigger slides with no results - walked the span of the headwall at ~9,000'.

Snowpack Observations

Full depth faceting of the thin snowpack. Solars have some crusts in the mix and a bit more strength but shadies are F or F- and dry. Found 12/7 SH preserved and standing tall up to 9,000', buried 25-30cm deep in this area. Distribution became spottier above this, probably due to both wind and sun affects. Seems quite likely that this layer will continue to be a significant problem in this area - we have yet to put enough of a slab on it to stress it to failure.

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: 12/7, down 25cm
Comments: Insignificant slab to create major issues, yet. I anticipate activity on this layer with additional loading