Wind Slabs 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, 01/05/2016 - 11:15
Location Map: 
United States
39° 13' 24.9708" N, 120° 14' 34.5732" 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: 
38degrees
Trigger type: 
Other - explain below
Crown Height: 
Less than 1 ft
Aspect: 
North
Weak Layer: 
Storm Snow
Avalanche Width: 
50ft.
Terrain: 
Above Treeline
Elevation: 
7 960ft.
Bed Surface: 
Storm Snow
Avalanche Length: 
100ft.
Number of similar avalanches: 
3
Number of people caught: 
0
Number of partial burials: 
0
Number of full burials: 
0
More detailed information about the avalanche: 

Oven-sized cornice pieces dropped onto wind-loaded, north facing, above treeline slopes triggered 6-8 inch deep wind slabs that propagated 30 to 50 ft across the slope and ran downhill for 75 to 100 ft. These slides occurred on 38-39 degree slopes. While these slabs were not very large they were very sensitive and continued to grow in size as new snow and wind loading continued throughout the day. 

Photos 1 & 2: 2 of the wind slab avalanches seen today on a 37-39 degree N facing slopes in near and above treeline terrain. 

Avalanche Photos: 
Avalanche observation video: 

Cornice Pieces Triggering Small Wind Slabs on Silver Peak

Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Precipitation: 
Snow
Air temperature trend: 
Static
Wind Direction: 
South
Accumulation rate: 
Greater than 1 in. per hour
More detailed information about the weather: 

New snow amounts of 6-8 inches in the Silver Peak area as of noon. Between 10:30 and 12:00 3-4 inches of new snow fell. Winds did not remain consistent and strong, and often the winds were calm even above treeline. Still during the times when the wind speeds were stronger some active wind loading was still occurring on near and above treeline leeward slopes.