Avalanche near Donner Summit

Location Name: 
Donner Summit
Region: 
Donner Summit Area
Date and time of avalanche (best estimate if unknown): 
Wed, 12/29/2010 - 04:00
Location Map: 
United States
39° 20' 39.8256" N, 120° 19' 51.1644" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Obvious avalanche path
Terrain Trap
Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
dry,slab,
Slope: 
40degrees
Trigger type: 
Natural
Crown Height: 
2 ft
Aspect: 
Northeast
Weak Layer: 
Storm Snow
Avalanche Width: 
40ft.
Terrain: 
Near Treeline
Elevation: 
7 200ft.
Bed Surface: 
Storm Snow
Avalanche Length: 
100ft.
Number of similar avalanches: 
3
More detailed information about the avalanche: 

I noticed this slide while driving to Castle Peak. It occurred on the north side of I80 on one of the steep rollovers that was windloaded. I saw three other similar but slightly smaller slides on similar terrain in that area.

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: 
Cooling
Wind Direction: 
Southwest
Accumulation rate: 
Greater than 1 in. per hour
More detailed information about the weather: