Pro Field Report

Basic Information

Observation Details

Observation Date:
December 25, 2019
Submitted:
December 25, 2019
Observer:
SAC - Davis
Zone or Region:
Soldier and Wood River Valley Mtns
Location:
Soldier Mountains - Peak 2

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
Widespread
Large collapses on S, SE and E-facing slopes above 8,000'. Cracking in isolated, very small, wind slabs along upper elevation ridgeline of Peak 2.

Snow Stability

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

Bottom Line

The (12/7) surface hoar layer is alive and well here. Collapses were slope-wide and wrapped into more south-facing terrain at the middle/upper elevation boundary than expected. The collapses were occurring in terrain that hadn't seen appreciable wind affect in the last storm.

I was surprised by the relative lack of wind affect on Peak 2 which is well known to be the most inhospitable place in the lower 48. There is still a good amount of light dry snow to blow around should we see a N or NW wind event later on Friday or Saturday.

Media/Attachments

These small slab and loose snow avalanches occurred during and and shortly after the Christmas Eve storm. Soldier Mountains, E-aspect at 9800'.
Some small sun-induced loose avalanches.
Wind-affected ridges in the Soldier Mountains.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Sunny
Temperature:
Inverted
Wind:
Light , W

Inverted temps. It was quite warm at middle elevations by midday. Bouts of sun with increasing clouds in the afternoon.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
1-2 Crest of the Soldiers
SE 9800 		D2 HS I-New/Old Interface Although it was hard to tell from my photos it appeared that at least two of the slides I saw were small wind slabs.
These small slab and loose snow avalanches occurred during and and shortly after the Christmas Eve storm. Soldier Mountains, E-aspect at 9800'.
Several Crest of the Soldiers
SE 8000-10000 		D1 L N-Natural Midday sun-induced loose. None

Snowpack Observations

HST: 8-10"

Snowpack Tests (ESE, 8,200'):
ECTP18, 22, 25 down 60cm on SH 191207
PST 40/100 End on same layer

Video link: https://www.instagram.com/p/B6g5LS4lY0C/

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: 50-60
Comments: The transition from a crust at sunnier, lower elevation slopes to a problematic faceted layer at shadier, middle and upper elevations was abrupt. I was getting large collapses on (12/7) where SH was hard to identify and far from an obvious grey stripe.

Terrain Use

I avoided avalanche terrain.