Cornice Collapse in Negro Canyon

Location Name: 
Negro Canyon
Region: 
Donner Summit Area
Date and time of avalanche (best estimate if unknown): 
Sat, 03/05/2011 - 11:00
Location Map: 
United States
39° 20' 48.3144" N, 120° 17' 48.228" W
See map: Google Maps
US


Red Flags: 
Recent loading by new snow, wind, or rain
Observation made by: Public
Avalanche Observations
Trigger type: 
Natural
Aspect: 
Northeast
Terrain: 
Above Treeline
Elevation: 
7 600ft.
More detailed information about the avalanche: 

From the top of Donner Ridge, significant cornice collapse was obvserved on a NE facing ridge in Negro Canyon.  The large blocks that fell did not trigger an avalanche.  Significant wind loading and wind slab was observed on the NE aspect of Donner Ridge at 7800 feet. 

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Air temperature: 
Above Freezing
Wind Speed: 
Moderate
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
West
Accumulation rate: 
None
More detailed information about the weather: