Wind slabs failing on Silver Peak

Location Name: 
Silver Peak
Region: 
Cabin Creek, Deep Creek, or Pole Creek Area
Date and time of avalanche (best estimate if unknown): 
Tue, 02/28/2012 - 11:00
Location Map: 
United States
39° 13' 24.4272" N, 120° 14' 47.8104" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Obvious avalanche path
Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
dry,slab,
Slope: 
36degrees
Trigger type: 
Natural
Crown Height: 
1 ft
Aspect: 
Northeast
Weak Layer: 
Storm Snow
Avalanche Width: 
100ft.
Terrain: 
Above Treeline
Elevation: 
8 120ft.
Bed Surface: 
Storm Snow
Avalanche Length: 
200ft.
Number of similar avalanches: 
2
More detailed information about the avalanche: 

Along the N Ridge of Silver Peak, two natural avalanches occurred around midday due to newly formed wind slabs failing above the low density snow from Monday's storm. These slabs averaged about 1 ft deep in this area. Large shooting cracks had formed along the ridge near these slides. The snowpack continued to collapse and crack in response to the weight of a skier on the ridge. The likely trigger for these slides was a natural cornice collapse.

Photo 1: 2 avalanches on a NE aspect at about 8120 ft on a 36 degree slope.

Photo 2: The shooting cracks along the ridge above these slides.

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Air temperature: 
Below Freezing
Wind Speed: 
Strong
Precipitation: 
None
Air temperature trend: 
Cooling
Wind Direction: 
Southwest
Accumulation rate: 
More detailed information about the weather: