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Professional Observation

Basic Information

Observation Details

Observation Date:
January 19, 2020
Submitted:
January 20, 2020
Observer:
SAC - VandenBos
Zone or Region:
Galena Summit and Eastern Mtns
Location:
Baker Creek - Summer TH to Baker/Big Smoky divide

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced

Snow Stability

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

Bottom Line

Buried persistent weak layers continue to heavily affect terrain selection.

Advanced Information

Weather Summary

Cloud Cover:
Clear
Temperature:
mid to upper 20s F (est)
Wind:
Light , W

Light westerly winds at ridgetop, otherwise calm and clear all day. WSW-SSE took a crust on slopes steeper than low 30s

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
2 Past 24 hours
SW 8,500-8,800' 		D1.5 SS 30-40cm (?) N-Natural Observed two crowns above the Norton drainage that appeared very fresh. On one, roller balls led up to the crown but were not present on bed surface, indicating that avalanche likely post-dated or was triggered by solar influence.
This avalanche was observed in the Norton Creek tributary of Baker Creek on 1/19/2020. If you look closely, you can see that many of the rollerballs coming off the cliff at the top of the image do not extend onto the bed surface of the slide. This indicates that the slab released either after or simultaneously with the rollerball activity, which likely occurred during the day on Sunday.
1 Within the past week Upper Main Fork of Big Smoky
9,000' 		D2.5 O-Old Snow 100cm N-Natural ~800-1,000' wide set of crowns, heavily wind-loaded terrain, likely failing on persistent weak layer near ground.
1 Within the past week Upper Prairie Creek
S 9,800' 		D2.5 O-Old Snow N-Natural
1 Within the past week Easley, S-SW
S 10,500' 		D2.5 O-Old Snow N-Natural Unreported as of yet, crown looks far from fresh, but based on amount of snowfall and intensity of wind in the Boulders I suspect that this likely happened during the recent multi-day storm.
Avalanche debris and crowns in bowl southeast of Easley Peak

Enough middle and upper elevation activity to point to a persistent problem on solars.

Snowpack Observations

Several strong wind events have made for a variable snowpack in middle and upper elevations in this drainage. Difficult to point at a layer and guess its date with confidence, particularly on solars. Small-grained (2-3mm) facets and subtle crusts+facet combos on solars seem to be the layers of most concern. Attempted to find a moderately represntative snowpit site to get a better handle for problem layer in 01/15/20 accident, but found that snowpack variability made this difficult.

Apparently fresh slabs in Norton seemed to indicate that settling/changing slab properties as a result of solar input could have at least temporarily decreased stability.

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
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