Skier triggered windslab on Anderson Ridge

Location Name: 
Anderson Ridge
Region: 
Donner Summit Area
Date and time of avalanche (best estimate if unknown): 
Wed, 02/05/2014 - 11:00
Location Map: 
United States
39° 16' 25.536" N, 120° 18' 31.0284" W
See map: Google Maps
US


Red Flags: 
Recent loading by new snow, wind, or rain
Observation made by: Public
Avalanche Observations
Avalanche Type: 
Slab
Slope: 
35degrees
Trigger type: 
Snowboarder
Crown Height: 
1 ft
Aspect: 
Northeast
Weak Layer: 
Old Snow
Avalanche Width: 
50ft.
Terrain: 
Above Treeline
Elevation: 
7 900ft.
Bed Surface: 
Old Snow
Avalanche Length: 
70ft.
Number of similar avalanches: 
3
More detailed information about the avalanche: 

Skier triggered windslab on a northeast aspect above tree line at ridge top. Avalanche was triggered from a convex roll at riders feet, and propagated around 15m and slid for 20m. Avalanche never got past a gliding motion, and would rate as a D1. We triggered several smaller windslabs on same aspect/elevation throughout the day, and noticed 3 other natural avalanches on same aspect/elevation. (sorry for poor quality of photos) 

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
Clear
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Precipitation: 
None
Air temperature trend: 
Static
Wind Direction: 
Northwest
Accumulation rate: 
None