Pro Field Report

Basic Information

Observation Details

Observation Date:
December 5, 2022
Submitted:
December 6, 2022
Observer:
SAC - Scott Savage
Zone or Region:
Soldier and Wood River Valley Mtns
Location:
Wells Summit - Soldier Mtns (most aspects 5800-7200')

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced
I was mostly riding a sled on a groomed road when traveling, so I was not in much terrain where I could have caused collapses.

Snow Stability

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

Bottom Line

Scary surface hoar layer buried about 1.5-2 feet down on shadier aspects, even in wind-exposed terrain - I don't trust it at all right now. Middle and lower elevation W-SW-S aspects lacked the surface hoar layer and had a snowpack with a better-looking structure. There was obvious recent wind-loading near most exposed ridgetops.

Media/Attachments

Snowpit on a NE aspect near 7150' on Wells Summit in the Soldier Mtns. The layer of surface hoar buried 1-2 feet deep failed easily in stability tests and should not be trusted in the coming days.
Snowpit on a SW aspect near 6950' on Wells Summit in the Soldier Mtns. This snowpit looks much better than shady aspects at the same elevation because it lacks the large buried surface hoar and/or weak facets in the middle of the snowpack.
Wells Summit - Soldier Mtns, NE aspect near 7150': Large surface hoar crystals sticking out of the bottom of a 1.5 foot thick slab after it failed during a stability test.
Obvious wind-loading at middle elevations in the Soldier Mtns.
Wind-exposed pit location just above Wells Summit where 1-2cm tall SH was buried intact about 50cm deep.

Advanced Information

Weather Summary

Cloud Cover:
Clear
Temperature:
20s F
Wind:
Calm
New/Recent Snowfall:
HST=10cm settled from the weekend storm

There is plenty of snow available for transport. W-SW-S slopes had a radiation recrystalization crust that formed yesterday and/or today. Many slopes had small (0.3-0.5cm) surface hoar on the surface.

Snowpack Observations

HS=50-80cm from 6000-7300'
Shady aspects: SPOOKY SH layer buried 30-60cm down (see photo above and profile below), ECTP10,11 and PSTend25
Sunny aspects (W-S-SW): No clean breaks in stability tests, and the structure doesn't look too bad (see photo above and profile below)

Snowpit profile on a NE aspect near 7150' on Wells Summit in the Soldier Mtns.
Snowpit profile on a SW aspect near 6950' on Wells Summit in the Soldier Mtns.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Persistent Slab
Isolated
Specific
Widespread
 Unknown
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 30-50cm
Weak Layer(s): Nov 27, 2022 (FC)
Comments: Location is shaded where surface hoar was directly observed. 1-2cm SH was buried intact in this area, even in at least some normally windy areas. See photos.
Wind Slab
Isolated
Specific
Widespread
 Unknown
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
 Layer Depth/Date: 30-60cm (estimated)
Comments: Shaded locations represent where I saw the majority of the wind slabs in this area. See photo for wind-loading patterns.

The surface hoar layer is at a depth (1-2 feet) and burial age (10 days) where it is likely to behave unpredictably: you may be able to trigger avalanches on this layer, even though you may not observe obvious signs of instability (cracking and collapsing). There is enough of a slab to produce large avalanches, but the SH crystals are getting embedded in the layers above and below. There may be portions of slopes that are more resistant to triggering avalanches, and spots on slopes where you could trigger an avalanche that "rips out" the previously mentioned "resistant" portions.

Terrain Use

I avoided avalanche terrain (solo travel, and in assessment mode).