Natural wind slab avalanche 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): 
Wed, 03/20/2013 - 16:00
Location Map: 
United States
39° 13' 23.5596" N, 120° 14' 47.7816" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Obvious avalanche path
Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
dry,slab,
Trigger type: 
Natural
Crown Height: 
2 ft
Aspect: 
Northeast
Weak Layer: 
Storm Snow
Avalanche Width: 
350ft.
Terrain: 
Near Treeline
Elevation: 
7 995ft.
Bed Surface: 
Storm Snow
Avalanche Length: 
500ft.
Number of similar avalanches: 
1
More detailed information about the avalanche: 

This wind slab avalanche on the north ridge of Silver Peak appeared to have been triggered by natural cornice collapse. Bed surface ranged from 35 to 39 degrees in slope angle. Observations on March 21st showed that the debris were covered with about 1 inch of storm snow, indicating that the avalanche occurred late day on March 20th. The failure layer was lower density storm snow (4F) under a higher density wind slab (1F). The crown was 1 to 2 feet deep in most areas with max height of 2.5 feet. Snowpit tests performed adjacent to the north flank indicated that the storm snow weak layer was now unlikely to propagate if collapsed.

Snowpit or crown profile photo or graph: 
Avalanche Photos: 
Avalanche observation video: 

20130321 Silver Pk Wind Slab Avy from 20120320.

Weather Observations
Air temperature: 
Precipitation: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: