V-Bowl Area - Recent Avy activity, high elev winds

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SNOWPACK OBSERVATION
V-Bowl Area
Submission Info
Forecaster
Saturday, February 18, 2017 - 2:00pm
Red Flags: 
Recent loading by new snow, wind, or rain
37° 55' 57.8064" N, 119° 12' 9.0648" W
Snowpit Observations
More detailed information about the snowpack: 

-Toured up V-Bowl, then NE along ridge to 10,000', checked out chutes, skied back down V-Bowl. 

-Knee deep skinning most of the way.  Sunny blue skies, with occasional episodes of low clouds moving in and obscuring view.  Mostly un-wind effected in V-Bowl, light unconsolidated powder in the morning, but quickly becoming effected by warmth and sun.  Interesting how NE, and even NNE aspects in the bowl up to and above 9,000' were warming and snow was getting thick, and developing frozen breakable melt-freeze crust by later afternoon.  Aspects More north than NNE were staying cold and lighter above 8000'.  Skiing was good if one stayed on the more northerly aspects, a touch heavy powder, but as any slope faced more easterly, snow was heavier or even had melt freeze breakable.  At 10,000', open mellow sloped NE aspects had very light in your face blower powder.   

-ECT tests in bowl and hand shears were not showing clean planar fractures, and not propagating.  

-Test pit dug at 9,000', NE aspect, see attached profile.  Many melt freeze layers underneigth recent storm snow, and snow still quite moist.  

-ECT at 9,800', just above steep convex roll of one of the main chutes resulted in no fractures or propagations.  Steeper slopes in this area at similar elevation showed lots of evidence of recent avalanches (during storm - storm slabs - 8-14" crowns), and one test cut in area that didn't slide released another pocket about 1ft deep (slopes >38 degrees).  Goes to show, stability tests are just a small part of figuring out actual slope stability!  Spatial variability can be significant even within relatively small areas.   

-Significant SW winds at higher elevations over Dana Plateau (12,500' down to 10,800') transporting snow.  See attached video.  These winds seem to die down toward later afternoon.  At elevations from 9,500; - 10,200', light southerly winds with moderate gusts, with some visible wind effect, but could not find evidence of significant wind slabs.  Exposed slopes above 10,200 : significant evidence of wind effecting surface snow.

-In summary:  Storm slabs on steep slopes are still sensitive today.  Wind loading occuring today at upper elevations, with evidence of natural wind slab releases - sensitive wind slabs up high!  

       

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Snowpit videos (tests, etc): 
Weather Observations
Blowing Snow: 
Air temperature: 
Wind Speed: 
Precipitation: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: 

-Lots of sun, with some periods of low clouds.  Temps just barely above freezing at 9,000' at noon, but sun and calm wind at that elevation kept it feeling quite warm ... t-shirt skinning - see attached photo(also note ski penetration).    

-Visible wind transport at elevations above 10,500'.

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