Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
January 24, 2020
Submitted:
January 24, 2020
Observer:
Lundy
Zone or Region:
Sawtooth and Western Smoky Mtns
Location:
Iron/Goat Creek Divide - Northern Sawtooths

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced

Snow Stability

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

Bottom Line

Observations today primarily from mid-elevations. Persistent weak layers are buried 4-5 feet deep and would be difficult to trigger, but the snowpack structure remains concerning.

Advanced Information

Weather Summary

Cloud Cover:
Obscured
Wind:
Moderate , W

Light snow flurries on and off in the morning. There was a brief, intense period of snowfall in the early afternoon that dropped 1-2 inches. There were a few breaks in the clouds and gusty W to NW winds around 3pm - seemed indicative of the frontal passage. The wind was moving snow at ridge level, but I did not see any sensitive wind slabs.

Snowpack Observations

Snowpack observations were from 6500 to 9100' on primarily easterly aspects. I focused primarily on mid elevations. Pole pokes at lower elevations revealed 60-90cm of snow depth with fairly obvious weak snow at the ground. Above about 7500', the snow depth quickly increased into the 120-180cm range.

I dug on E at 8250' and SE at 8700'. In both of these locations, I could pick out a subtle weak layer about 120cm down that was likely 12/31, as well as more obvious basal facets down 150cm. The possible 12/31 layer was more pronounced on the solar aspect, where a P hard slab sat on a layer of 1F rounding facets. The basal layer was more pronounced on the E aspect, where there was 5-7cm of 3-5mm DH sitting atop a crust on the ground. In neither location was there any sign of a weak layer in the top 120cm.

Persistent weak layers are buried 3-5 feet deep in the Sawtooths, Western Smokys, and Banner Summit area. This makes them difficult to trigger, but the resulting avalanche would be unsurvivable.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Persistent Slab
Isolated
Specific
Widespread
Unknown
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
Layer Depth/Date: 120-150cm
Comments: Sensitivity was not tested in any way, but would suspect Unreactive based on depth.

Terrain Use

I ventured into terrain in the low 30s on sheltered slopes where the snowpack was uniformly deep.