Pro Field Report

Basic Information

Observation Date:

December 7, 2022

Submitted:

December 9, 2022

Observer:

SAC - VandenBos (off duty), Peterson

Zone or Region:

Soldier and Wood River Valley Mtns

Location:

East Fork Big Wood (6,300-8,500', primarily W-NW-N-NE)

Recent Avalanches?

Yes

Cracking?

Isolated

Collapsing?

Widespread

As soon as we got into a bit of wind-affected terrain we experienced widespread collapsing. Avalanches observed refers to recent small wind slabs.

Stability Rating:

Fair

Confidence in Rating:

Moderate

Stability Trend:

Steady

Advanced Information

Cloud Cover:

Clear

Wind:

Calm

Clear, calm, and inverted.

Avalanche Observation Comments:

We observed several small wind slabs that appeared to be somewhat fresh, likely from Sunday's new snow+wind. We observed extensive cracking from around 12/1 (date estimated) on just about every slope that was steeper than about 25. We did not look into any bigger, steeper pieces of terrain but suspect you would have found similar cracking and natural avalanche activity.

HS=60-65cm, 11/27 interface is down 40-45 cm. On lower elevation slopes that weren't wind affected the snow overlying 11/27 wasn't much of a slab, the densest section was 4F-. Here, the slab was too weak to propagate fractures. As we climbed into more wind-exposed terrain we immediately began experiencing widespread collapsing, it didn't take much. We dug on a slope that had seen just a bit of wind stiffening (N at 7,600'), where HS =65cm. Snowpack tests returned ECTP2 and ECTP1 on the 11/27 interface, which presented as a layer of 10-15mm, standing, moderately intergrown SH flakes sitting on top of some very weak, advanced facets (2-2.5mm). The SH was integrating into the slab above

Surface: the snow surface has faceted significantly. In addition, we observed a widespread layer of standing SH everywhere that we traveled. Crystals were starting to lay down on westerly aspects, I suspect the sun has knocked them down a bit more on direct solars but this was not directly observed.

Problem	Location	Distribution	Sensitivity	Size	Comments
Persistent Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Layer Depth/Date: down 40-45cm Weak Layer(s): Nov 27, 2022 (FC)

Pro Field Report

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