Evil Twin Bowl, wet slab avalanche

Location Name: 
Evil Twin Bowl
Region: 
Goose Lake Area
Date and time of avalanche (best estimate if unknown): 
Thu, 02/09/2017 (All day)
Location Map: 
United States
45° 6' 31.8492" N, 116° 12' 0.1944" W
US


Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Rapid warming
Obvious avalanche path
Terrain Trap

Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
Wet
Slab
Trigger type: 
Natural
Crown Height: 
2 ft
Aspect: 
North
Weak Layer: 
Old Snow
Avalanche Width: 
200ft.
Terrain: 
Near Treeline
Elevation: 
7 600ft.
Bed Surface: 
Old Snow
Avalanche Length: 
700ft.
Number of similar avalanches: 
4
More detailed information about the avalanche: 

Avalanche in the middle of the bowl was R3,D3 wet slab that ran between 700 and 800 feet down through pinch and into bottom of path.  Several smaller avalanches were also visible in the chutes and steep terrain in the to the west of the bigger slide.  Saw similar avalanches in upper Twin Lakes area as well.

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
50% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Precipitation: 
Mixed rain and snow
Air temperature trend: 
Cooling
Wind Direction: 
Southeast
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

After above freezing conditions for previous 72 hours and rain above 8000 feet, the top of this ridge was supportable to the weight of a person.  The crust was approximately 2-3 inches thick due to a cooling trend.  Expecting the saturated snowpack to refreeze relatively quickly over the next 24 hours, or at least deep enough to lock up instabilities in the upper pack.