Stiff but seemingly stable wind slabs on Andesite Peak

Location Name: 
Andesite Ridge
Region: 
Donner Summit Area
Date and time of observation: 
Thu, 03/17/2011 - 13:00
Location Map: 
United States
39° 21' 2.9736" N, 120° 21' 58.3596" W
See map: Google Maps
US


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

Observations showed significant settlement in this area today. Settlement cones around trees and settlement cracks existed at all elevations. Hand pits and test pits showed a layer of dense snow on top of a layer of lighter snow near the top of the storm snow. These pits also showed that the wet snow below the storm snow has started to cool off and refreeze in some areas. Most stability tests on both these interfaces showed that the bonds between these layers are strengthening. A few of the tests did still show that fractures remain possible in some areas where firm wind slabs existed near and above treeline. These unstable tests occurred right next to tests that showed stable results.

Ski cuts on steep wind-loaded and non-wind-loaded test slopes and large refrigerator-sized cornice blocks dropped onto wind-loaded slopes did not result in any signs of instability.

By noon on the southerly slopes enough warming had occurred for the snow surface to become heavy and wet below 7600 ft.

Photo 1: Settlement cone around a tree.

Photo 2: Cornice blocks dropped onto a wind-loaded slope.

Snowpack photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
Clear
Air temperature: 
Below Freezing
Wind Speed: 
Light
Precipitation: 
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
More detailed information about the weather: