Avalanche on Wildflower Ridge

Location Name: 
Wildflower Ridge - Mt. Judah
Region: 
Donner Summit Area
Date and time of avalanche (best estimate if unknown): 
Wed, 12/30/2009 - 08:40
Location Map: 
United States
39° 18' 28.8108" N, 120° 19' 10.2684" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
dry,
Slope: 
43degrees
Trigger type: 
Natural
Crown Height: 
1 ft
Aspect: 
Northeast
Avalanche Width: 
300ft.
Terrain: 
Below Treeline
Elevation: 
7 760ft.
Bed Surface: 
Old Snow
Avalanche Length: 
50ft.
More detailed information about the avalanche: 

Avalanche triggered by natural cornice collapse. It is unclear if this was all one avalanche or several adjacent events that occurred within a short time period. Debris looked 1 to 2 hours old at 8:40am. Slope angle ranged from 38 to 48 degrees. Second photo shows significant wind transport of snow over ridgetop.

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