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Professional Observation

       

Basic Information

Observation Details

Observation Date:
December 20, 2021
Submitted:
December 20, 2021
Observer:
Josh Feinberg | Key Observer
Zone or Region:
Lee Vining
Location:
V- Bowl

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
Isolated
Collapsing? 
None Experienced

Snow Stability

Stability Rating: 
Very Good
Confidence in Rating: 
Moderate
Stability Trend: 
Improving

Key Points

 

9,700′, NNW aspect above V-Bowl (Lee Vining Can)Toured up from Lee Vining Can at 7,500′ up to ~10,000′ above V-Bowl and back down.  ~1ft of consolidated snow at lowest elevation supportable to skis, with 1.5 – 2ft+ up higher depending on wind stripping/deposition.

-Probed and dug a bunch on way up, and didn’t find any old Oct/Nov snow at the base of the snowpack until over 9,600′ on northerly facing terrain (a few hundred feet above the top of V-Bowl).

-Came across some small isolated areas of thin recent wind slab on cross loaded slopes above 9,500′, which failed easily with hand shear tests and some cracking that extended only a few feet away from skis.  Not too concerning here, but in steep consequential terrain, a small wind slab could end in nasty slide.  (see attached video below under media)

-When I finally did get high enough to find old early season snow at the base of the snowpack, dug a pit and ECT test propagated energetically with hard force on the basal facet layer. While this facet layer is certainly reactive in the test pit, at this point it is unlikely that a human could trigger it UNLESS they find just the right shallow point and hit it with a lot of force.  But a big heavy new load of snow coming this week could certainly trip the balance again.

Media

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy

Calm winds up to mid-elevations this afternoon, with light gusts near treeline.  Some visible turbulent snow transport cross-slope above tree line across the east facing chutes of Mt Wood and in the upper reaches of the valentine cirque, but nothing visible over ridge tops. Likely because SW winds previously have blown all the loose snow that they could already, leaving the windward side of ridge tops stripped.

Snowpack Observations

Most of the upper 2/3 of V-Bowl was wind effected with variable pockets of loose snow, firm wind board, and breakable.  The sheltered trees provided much more consistent soft snow, but scraped shallow rocks/trees/logs a bunch of times on way down.

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