Pro Field Report

Basic Information

Observation Details

Observation Date:
December 18, 2019
Submitted:
December 18, 2019
Observer:
SAC - Davis, Liles
Zone or Region:
Soldier and Wood River Valley Mtns
Location:
Dollarhide Summit - Shaw

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
Isolated
A few small collapses <30' radius on SE-facing slopes. Collapses occurred in shallower, previously wind-affected terrain at the 12/7 interface. In these locations 12/7 presented as facets.

Snow Stability

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

Bottom Line

We can add Dollarhide to the ever-growing list of locations that harbor both 12/7 and 11/26. Fractures on 12/7 only occurred after 30 loading steps in our ECTs but when it failed it was sudden planar and the slab slid easily.

Media/Attachments

The 12/7 weak layer on Shaw Mountain. This layer presented as surface hoar (pictured) on shadier aspects and as a crust on sunnier aspects.
Weak layers on Shaw Mountain.
Small, sun-induced loose snow avalanche on Shaw.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Wind:
Light , E

Overcast in the morning gave way to some clearing and sunshine in the early afternoon. Slight inversion but not as noticeable as yesterday.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
2 Shaw
S 8700 		D1 L I-New/Old Interface N-Natural Sun induced loose snow avalanches in steep rocky south-facing terrain.
Small, sun-induced loose snow avalanche on Shaw.

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: 30-50 cm, 12/7
Comments: There is a healthy (30-50 cm) and fairly dense (4F+) slab atop 12/7 in this location. It didn't produce any results in ECTs until we dropped the hammer after 30+ hits. Though when it did fracture it was sudden planar and the slab slid easily. 12/7 was a MFcr on sunnier aspects. There was some faceting below the crust but several hand pits along our route showed a generally good bond.
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: 60-90 cm, 11/26

Terrain Use

We elected to avoid avalanche terrain where 12/7 and 11/26 were prominent.