Professional Field Report

Basic Information

Observation Details

Observation Date:
January 7, 2020
Submitted:
January 7, 2020
Observer:
SAC - Savage, Frost, Skinner
Zone or Region:
Soldier and Wood River Valley Mtns
Location:
Wells Summit to Worswick Hot Springs: Wardrop, Basalt, Little Smoky, Red Rock Cks - 5400-7200', most aspects

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced
Lots of older, mostly small avalanches observed.

Snow Stability

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

Bottom Line

Two hour sled ride with the main goals being to look for recent avalanche activity and terrain familiarization in an area opened to public use last winter. Observed natural avalanche activity was on obvious wind-loaded features and cross-loaded slopes. No recent activity from past couple days.

Advanced Information

Weather Summary

Cloud Cover:
Partly Cloudy
Temperature:
20s F to low 30s F in parking lot
Wind:
Light

2-5cm (1-2") new snow from yesterday/last night, very little wind. Previous winds had moved a lot of snow on exposed slopes.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
10 Little Smoky Ck drainage near Carrie Ck and Worswick Hot Springs
S 6000-6500' 		D1.5 HS N-Natural We observed about 10 small (D1-1.5) slides on W, SW, S, SE, and E aspects. All occurred in obviously wind-loaded terrain at lower/middle elevations. They were a mix of soft and hard slabs.
Debris from small natural hard slab avalanche near 6200' on S aspect in Little Smoky drainage.
2 N Fork Soldier Ck - point 8238
S 8000' 		D2 U N-Natural Two slides observed on this face, S aspect and SE aspect. Both obviously wind loaded areas (strong NW wind event). None

Smaller slides failed on a mixture of 12/31 FC+crust and 12/7 FC+crust.

Snowpack Observations

30-90cm depth, much deeper as we moved north from Wells Summit. Surface was mixture of wind slab+sastrugi+decomposing powder. Some pinwheeling in surface snow below 6500' on W and SW (yesterday or day before?), but no new surface crusts observed. 12/31 FC+crust on solar aspects, just FC on shady. Solar slopes had obvious crust+FC at 12/7 layer, fairly low in the pack. Shady slopes had a mixture of SH and FC (SH more prominent closer to 7000'). No old Sept/Oct depth hoar noted. No formal tests performed. Non-standard hand shears and tap tests showed 12/31 layer was not very touchy but still produced clean shears.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wind Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 12/31
Comments: Snowmobilers had played on all the easily accessible little wind features near Wells Summit with no slides.
Persistent Slab
Isolated
Specific
Widespread
 Unknown
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 12/31, 12/7
Comments: 12/7 is widespread but differs in appearance (either SH, FC, FC+crust). 12/31 only seemed to be an issue on W-S-E, but this may have been as much due to wind-loading as the weak layer structure.

Terrain Use

We did not ride on slopes over 30* - most of the avalanche terrain near our route ended on roads or in terrain traps. We did comfortably travel in terrain traps (on roads alongside creeks) below ugly slide paths.