Density inversion and windslab on Flagpole

Location Name: 
Flagpole Peak
Region: 
Echo Summit Area
Date and time of observation: 
Thu, 04/12/2012 - 10:00
Location Map: 
United States
38° 50' 49.7796" N, 120° 3' 28.3716" W
See map: Google Maps
US


Red Flags: 
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Obvious avalanche path
Terrain Trap
Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 

Pic: A density inversion was observed throughout elevation range on skintrack up, with short cracks and small slab failures especially on skintrack switchbacks.

Video: Below Flagpole ridgetop, density inversion changed to dense windslab that was reactive to ECTs.

Winds were blowing graupel along snow surface downslope of ridge, and building windslab just below ridge. NW winds also contributing to crossloading far downslope from ridgetop.

Snowpack photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Precipitation: 
Snow
Air temperature trend: 
Static
Wind Direction: 
Northwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Strong gusts.