Professional Observation

Basic Information

Observation Date:

January 27, 2020

Submitted:

January 28, 2020

Observer:

SAC - VandenBos

Zone or Region:

Soldier and Wood River Valley Mtns

Location:

Eagle Creek

Recent Avalanches?

None Observed

Cracking?

None Experienced

Collapsing?

None Experienced

Stability Rating:

Fair

Confidence in Rating:

Moderate

Stability Trend:

Steady

Weak and thin snowpack observed on low and middle elevation terrain on the shady half of the compass in this zone. Not much of a slab currently, but this snowpack would not hold up well to significant, rapid loading.

Advanced Information

Cloud Cover:

Mostly Sunny

Temperature:

upper 20s F

Wind:

Calm

Calm day with a few passing clouds. Considerably cooler than previous day.

Thin and weak snowpack on the north half of the compass here. Went looking to see if warm ambient air temperatures had significantly changed the upper snowpack in these areas. Found that the upper 20cm of the snowpack had gained a bit of strength (4F) but not nearly enough to consistently keep you out of the facets below, even with fatter skis. Despite lack of a significant slab, weak snow near the ground is still producing repeatable, unstable snowpack test scores. Given lack of a significant overlying slab I was expecting to see ECTNs or ECTXs. However, 2 out of 3 of my ECTs propagated with light to moderate force on a well defined layer of weak snow near the ground. CPSTs and PSTs propagated to end in the upper teens to mid 20sBased on observations in this drainage in December and January and the presence of large, easily identifiable SH at this interface (10cm off the ground) I suspect this layer was buried 12/7.

Thin and weak snowpack in the Eagle Creek drainage. WNW aspect at 7,000'.

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: 12/7, down 60-70cm Did not shade upper as I did not directly observe SH there, but suspect it exists on many upper elevation slopes. Even without SH, I'd imagine this interface could produce real-world results when loaded.