Many avalanches Lee Vining Canyon from yesterday

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AVALANCHE OBSERVATION
V Bowl

Drainage:

Submission Info
Jessica May
Saturday, February 18, 2017 - 12:30pm
Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Rapid warming
Obvious avalanche path
Avalanche Type: 
Dry
Slab
Slope: 
35degrees
Trigger type: 
Natural
Crown Height: 
1 ft
Aspect: 
North
Weak Layer: 
Storm Snow
Avalanche Width: 
40ft.
Terrain: 
Below Treeline
Elevation: 
9 300ft.
Avalanche Length: 
40ft.
Number of similar avalanches: 
4
More detailed information about the avalanche: 

Toured up the ridge looker's left of V Bowl to the top of the nob then down the ridge and steep north facing trees that side of V Bowl. 

While skiing down the steep trees we saw 5 small (D1) avalanches in the trees.  Each was 30 - 50 feet wide and had started on convexities above trees or along ribs.  They had about 8 inches of visible crown and had at least 10 cm of new snow on top of them.  Failure seemed to be within the storm snow, probably during the storm yesterday afternoon.

We also saw 2 slides originating on the southwest face of Mono Dome well up canyon from us but below the Warren Fork that crossed 120.  Probably from yesterday.  There were widespread small wet point releases on the southern aspects of Mono Dome as well.  Also some small (wet?) point releases on the looker's right of V Bowl itself, more eastern aspect.  The point releases were probably from when it warmed up this morning.  We didn't see any occur though.

The main V Bowl Chute slid from top to bottom.  We could see a crown just under the top spreading most of the width of the entrance and the toe of the debris was visible down at about 7800 feet just before it really mellows out.  This had less snow on top of it and a clear crown, so perhaps from later in the day yesterday while the wind was blowing?

There were also several debris fields running onto the upper portions of the plateau from East Peak and Dana.  They were all well covered with new snow and none of the crowns were visible so they probably happened during the heavy snow yesterday.

We dug several hand pits on the way up and found regular easy and very easy planar failures 25 - 35 cm down at a density change from F to 4F-, I couldn't get a failure at the new/old interface.  New snow ranged from 45 to 60 cm deep.  North aspects were still soft winter powder but anything south or east was developing quite a sun crust.  In places earlier in the day just moist snow but on the way down there were crusts ranging from 1-5 cm deep, 1F hard on top of the F new snow.  At 1330 and 9400 ft elevation, ENE, Tair = 4.5 C and Tsurf = 0. 

Skiing varied from difficult breakable crusts to bottomless powder.

Blowing Snow: 
Yes
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Light
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
None
More detailed information about the weather: 

Calm winds down low, light SW winds on the plateau.  Visible snow transport from the SW on East and Dana off and on throughout the day.  Unexpectedly warm weather, snow falling off trees all over including at higher elevations.
 

37° 55' 28.5528" N, 119° 11' 32.604" W

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