Snowmobile triggered above the road

Location Name: 
Just above the Fisher Cr Road
Region: 
Fisher Saddle Area
Date and time of avalanche (best estimate if unknown): 
Sun, 02/03/2019 - 14:49
Location Map: 
United States
45° 7' 56.4852" N, 116° 7' 30.8568" W
US


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain

Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
Slab
Slope: 
35degrees
Trigger type: 
Snowmobiler
Crown Height: 
1 ft
Aspect: 
East
Weak Layer: 
Old Snow
Avalanche Width: 
40ft.
Terrain: 
Below Treeline
Elevation: 
7 100ft.
Bed Surface: 
Old Snow
Avalanche Length: 
20ft.
Number of similar avalanches: 
2
More detailed information about the avalanche: 

 Yesterday, after we talked to a snowmobiler that set of a shallow slab near the road bank on the Fisher Cr Road, we took this photo. The convexity was un-supported at the bottom.

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: 
Cooling
Wind Direction: 
Southwest
Accumulation rate: 
Greater than 1 in. per hour