Pro Field Report

Basic Information

Observation Details

Observation Date:
December 23, 2020
Submitted:
December 23, 2020
Observer:
SAC - Ethan Davis
Zone or Region:
Soldier and Wood River Valley Mtns
Location:
E. Fork Baker Creek - Fox Peak (All aspects, 7,000-9,200')

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
Isolated
Collapsing? 
Isolated
Unstable pockets of wind slab isolated to near ridgelines.

Snow Stability

Stability Rating: 
Fair
Confidence in Rating: 
Moderate
Stability Trend: 
Steady

Bottom Line

Avalanches are most likely to be triggered in areas with a stiff wind-deposited slab. In areas sheltered from the wind, only 6-8" of relatively soft snow sit above the weak facets caused by the drought which ended ~10 days ago.

I found isolated, sensitive, wind slabs up to 2 feet thick. These drifts + my weight caused collapses and a small release in a wind-loaded pocket near a ridgeline.

Media/Attachments

Slab that released center left and triggered another small slab below the cliff.
A series of persistent slab avalanches near Baker Creek. Crown lines can be found above, below and to the sides of the main cliff band.
Avalanches at the head of Baker Creek in the Smoky Mountains.
Avalanche near Fox Peak in the Smoky Mountains.
Snow depths on Fox Peak varied from 40-70 cm. There was only about 15-20 cm of snow above the weak snow we buried on 12/11 and 12/13. Warming on the solstice seemed to have very little lasting impact here aside from leaving a melt-freeze crust near the surface.
This small drift of wind-loaded snow released about 50 feet from me after the slope I was on collapsed. The bed surface was the melt-freeze crust that formed on the solstice. There were cracks in the bed surface that reached to the December facet layer.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Sunny
Temperature:
20s
Wind:
Calm

Mostly clear and calm. Single digits in the valley in the morning, upper-teens to low 20s F higher up by midday.

Avalanche Observations

There were numerous small slab avalanches near the Smoky Crest near the Headwaters of Baker, Apollo and Brodie as well as some in Newman Basin. Most were observed on East and Southeast aspects, although this is likely biased by my location (no avalanches to look at back to my East). None were particularly large (mostly D1-D1.5) with a couple of possible D2s.

Smaller persistent slabs dotted some terrain closer to E. Fork Baker and I was able to trigger one small drift in fresh wind slab that also broke into the early season drought facet layer.

Snowpack Observations

Overall snow depth is still shallow (40-70 cm). In sheltered areas, only 15-25 cm of snow sits atop the (12/11) interface. In wind-loaded locations, I found 1F slabs up to 60 cm thick.

Melt-freeze crusts were present at the surface on all aspects and elevations to 9,200 feet. This layer acted as the primary bed-surface in the small wind-drift that released.

Snow below the crust remained cold and dry, very similar to how it appeared prior to last weekends storm.

Snow depths on Fox Peak varied from 40-70 cm. There was only about 15-20 cm of snow above the weak snow we buried on 12/11 and 12/13. Warming on the solstice seemed to have very little lasting impact here aside from leaving a melt-freeze crust near the surface.

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: 30-60 cm
Weak Layer(s): Dec 11, 2020 (FCsf)
Comments: Got a couple of collapses on this layer that shook loose a wind drift and cracked down to the facets below.

Small wind drifts were scattered and sporadic with only an inch or so of new snow in the last few days.

Terrain Use

I felt comfortable traveling anywhere that lacked a stiffer slab near the surface. I avoided steep, recently wind-loaded slopes.