Avalanche on Powderhouse

Location Name: 
Powderhouse Ridge
Region: 
Luther Pass Area (including Job and Freel)
Date and time of avalanche (best estimate if unknown): 
Fri, 02/10/2017 - 21:00
Location Map: 
United States
38° 46' 58.9116" N, 119° 58' 51.9636" 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
Terrain Trap
Observation made by: Professional Observer
Avalanche Observations
Avalanche Type: 
Dry
Slab
Slope: 
40degrees
Trigger type: 
Natural
Crown Height: 
3 ft
Aspect: 
North
Weak Layer: 
Storm Snow
Avalanche Width: 
150ft.
Terrain: 
Near Treeline
Elevation: 
9 100ft.
Bed Surface: 
Old Snow
Avalanche Length: 
150ft.
Number of similar avalanches: 
1
More detailed information about the avalanche: 

Two adjacent avalanches on Powderhouse that appear to have run on 2/10/17 around 9100 feet on the ridge. These appear to have run naturally. The lower slide was approximately 100 feet wide by 150 feet long. The steepest portion of the starting zone was 40 degrees. After excavating blown in snow, the crown meaured at 100 cms. 

A very similar and larger slide occured roughly a hundred feet higher on the ridge. This one was wider and ran further into the trees below (roughly 250 wide by 200 feet long). Almost no crown was still visible at this location due to a slightly more wind exposed position. 

Both slides ran through trees.

Avalanche Photos: 
Avalanche observation video: 

Wind Slab Avalanche on Powderhouse

Weather Observations
Air temperature: 
Precipitation: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: