Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
December 29, 2021
Submitted:
December 29, 2021
Observer:
Pro
Zone or Region:
Galena Summit and Eastern Mtns
Location:
Durrance (6300'-7900', East to Southwest)

Signs of Unstable Snow

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

Snow Stability

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

Bottom Line

Even though many slopes off Durrance held no snow prior to the onset of two larger long-running storms starting three weeks ago, brief lapses in snowfall allowed for weak layers to form. As the new snow settles and forms a denser slab, these weak layers may start becoming more reactive. I found surface hoar on multiple aspects and elevations up to 7900' that propagated in both pits.

Media/Attachments

Advanced Information

Weather Summary

Cloud Cover:
Overcast
Wind:
Calm

Fluctuated between lulls in snowfall and s-1

Snowpack Observations

Two pits, one on a S aspect on the standard approach ridge, one on the furthest west treed ridge on a SE aspect. The ECTN scores around 60cm appear to be a buried NSF layer.

S, 6840': HS 90cm, ECTN10 @ 73cm, ECTN13 @ 60cm, ECTP24 @ 38cm.

SE, 7000': HS 95cm, ECTN6 @ 80cm, ECTP20 @ 30cm

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Persistent Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
Layer Depth/Date: 35-40cm
Comments: Surface hoar buried in lull between last 2 storms, noted on multiple aspects in multiple zones in this area

Terrain Use

I was skiing solo and did not have high enough confidence in where the surface hoar was and was not to enter terrain above 30 degrees. It appears to be widespread as I found it in Eagle Creek, and may become more reactive as the new snow settles and form a more cohesive slab.