Pro Field Report

Basic Information

Observation Details

Observation Date:
January 11, 2022
Submitted:
January 11, 2022
Observer:
SAC - Davis
Zone or Region:
Soldier and Wood River Valley Mtns
Location:
Lower Soldier (SW-S-E, 7,500-9,500')

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced
Explosive triggered slide on Peak 2.

Snow Stability

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

Bottom Line

I saw small natural wind slab avalanches in the foothills of the Soldiers as well as a natural wind slab avalanche along the Soldier Crest (both at least 4 days old). One explosive triggered avalanche (1/10/22) was noted in the Soldier Cat Ski terrain. I did not observe any signs of instability. Snowpack tests did not show propagating results on any layer.

Media/Attachments

Small, natural wind slab avalanches on E-facing slopes in the Soldier Foothills. There were several of these that likely released during strong WSW-W-WNW wind on 1/6 or 1/7.
This wind slab avalanche was triggered with explosives during avalanche control work on 1/10/22 by Soldier Mountain Cat Skiing. E-ESE facing slope at 9,300'.
There is a blown in crown and flank visible about 100' off the ridge line in the smooth-looking chute. NE of Smoky Dome on a SE-facing slope at 9,700'.
Highmark tracks in wind-loaded upper elevation SE-facing terrain of the Soldiers.
This wind slab avalanche was triggered with explosives during avalanche control work on 1/10/22 by Soldier Mountain Cat Skiing. E-ESE facing slope at 9,300'.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Temperature:
Low 30s F
Wind:
Light , NW

Diffuse sun but no real warming of the snow surface on steeper south-facing terrain at 8,000'. Light WNW-NW wind. No snow left for transport with W-WNW-NW wind.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Jan 7, 2022
(+/- 3 days) 		NE of Smoky Dome
SE 9700ft 		D2 N-Natural
There is a blown in crown and flank visible about 100' off the ridge line in the smooth-looking chute. NE of Smoky Dome on a SE-facing slope at 9,700'.
Report
1 Jan 10, 2022
(Exact) 		Peak 2
SE 9300ft 		D1.5 HS-Hard Slab I-New/Old Interface AE-Explosive Surface
c-Intentional
This wind slab avalanche was triggered with explosives during avalanche control work on 1/10/22 by Soldier Mountain Cat Skiing. E-ESE facing slope at 9,300'.
This wind slab avalanche was triggered with explosives during avalanche control work on 1/10/22 by Soldier Mountain Cat Skiing. E-ESE facing slope at 9,300'.
Report
NE of Smoky Dome
Peak 2
 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
10 Soldier Foothills
E 5,000-7,000' 		D1 HS Small, natural wind slab avalanches on E-facing slopes in the Soldier Foothills. There were several of these that likely released during strong WSW-W-WNW wind on 1/6 or 1/7.
Small, natural wind slab avalanches on E-facing slopes in the Soldier Foothills. There were several of these that likely released during strong WSW-W-WNW wind on 1/6 or 1/7.

Snowpack Observations

My main objective was weather station maintenance. Of note, the HS under the snow sensor at L. Soldier is 105 cm, but the HS in the immediate vicinity is 130-150 cm. It's hard to find a spot without some sort of subtle wind affect in this drainage, even at the weather station.

Quick snowpack Obs:
8,000' E, HS 130-155 cm.
ECTNs in upper 50 cm.

8,000' SE, HS 105-115 cm.
Subtly wind-loaded location.
ECTN11 down 15 cm, ECTN16 down 30 cm.
4F slab atop a couple of thin 1-2 cm facet layers (down 30 to 40 cm). I suspect (1/3) is one of these.
1F/1F+ below that with no obvious weak layers.
No October snow.

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: 30-40 cm
Weak Layer(s): Jan 3, 2022 (MFcr)
Comments: Shaded where observed. Noticeable layer but not propagating in ECTs. Likely the culprit with the explosive triggered slide higher up on Peak 2.

Terrain Use

My objective for the day kept me on mostly low-angle terrain and groomed trails.