Natural Avalanche R2D2 Table Mtn - Multiple trigger locations

AVALANCHE OBSERVATION
Table Mtn

Drainage:

Submission Info
Josh Feinberg
Forecaster
Sunday, February 23, 2020 - 10:30am
Red Flags: 
Recent loading by new snow, wind, or rain
Rapid warming
Avalanche Type: 
Dry
Slab
Loose/Point-Release
Slope: 
38degrees
Trigger type: 
Natural
Aspect: 
Northeast
Weak Layer: 
Storm Snow
Avalanche Width: 
80ft.
Terrain: 
Above Treeline
Elevation: 
11 400ft.
Bed Surface: 
Old Snow
Avalanche Length: 
800ft.
Number of similar avalanches: 
2
Number of partial burials: 
0
Number of full burials: 
0
More detailed information about the avalanche: 

Avalanche occured on a ENE facing slope just above tree line starting in a rocky/cliffy area (11,400', ~38° slope).  There was at least two seperate release points, perhaps even 3.  I could tell that atleast one started as a loose point release from warming east facing rocks, the other two I couldn't tell exactly, but feel confident that they were triggered by warming rocks as well, and by the width and length of the combined path they may likely have been small slabs.  In any case, they appeared to occur in wind deposited snow  These slides just entrained the new surface snow and ran on the firm old snow surface for the most part, and didn't appear to step down at all into the old snow crust/facet combos.  The max width of the path was ~80', and it ran 800 vertical feet.  R2D2, it could have buried someone.  I climbed up to check this slide out in the mid to late afternoon, quite a while after the rocks on this slope had gone into the shade.  Sourounding surface snow on this slope was all cold, dry, and loose.           

On the approach at mid-elevation, ~9800', one whoomph and collapse was felt in a slight gully feature with visible cracks ~15' out forming from the surface crust under the new snow collapsing on the facets underneigth.  East facing terrain, ~24° slope.     

~4" of new snow was found around 9200', and 5-6" above 10,000'.  Lots of loose faceted snow under new snow, with very varable crusts across the landscape, some surface, some buried (quite a rotten snowpack at all elevations!).  Skinning was often boot top to knee deep down into the facets, and even to the thigh in some places(See pic) - challenging skinning at times using ski crampons, and boot crampons for short period where near surface crusts were supportable (which wasn't for long).    Entry and exit into this area was a pain with thick aspens and willows to navigate thru.  The snow however in open areas above this was soft and forgiving for the most part on non-sunny slopes.  Some big honking cornices at the ridgetop, presumably quite old.  When things really warm up later this season they could be quite dangerous.  

Avalanche Photos: 
Avalanche observation video: 
Blowing Snow: 
Yes
Cloud Cover: 
Clear
Air temperature: 
Above Freezing
Wind Speed: 
Moderate
Precipitation: 
None
Wind Direction: 
West
Accumulation rate: 
None
More detailed information about the weather: 

-10,200', 2:30pm, air temp=2°C.  Calm winds except at ridge top where occasional gusts from the west could be seen blowing snow into the air (see attached video).   

Number of People Caught: 
0
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