Intentional cornice collapse triggers 1 foot wind slab on test slope.

Location Name: 
Incline Lake Peak
Region: 
Mount Rose Area
Date and time of observation: 
Mon, 03/03/2014 - 10:25
Location Map: 
United States
39° 17' 40.488" N, 119° 56' 28.068" W
See map: Google Maps
US


Red Flags: 
Recent loading by new snow, wind, or rain
Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

Intentional collapse of refrigerator size cornice triggered a wind slab avalanche on a small test slope. Aspect NNE, elevation 9,500', slope angle 44 degrees, near treeline terrain. Test slope failed 3 m wide and the slab was 35 cm thick. Slab was 4F+ hard and weak layer was F hard storm snow. ECT performed on the crown scored ECTP-12 on the same weak layer and bed surface.

Instability in the area seemed limited to near treeline and above treeline wind loaded areas along ridgelines and near treeline cross loaded spine features. No evidence of instability was observed in wind protected areas below treeline.

Snowpit videos (tests, etc): 

20140303 1025001

Weather Observations
Blowing Snow: 
No
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Light
Precipitation: 
Snow
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour