Wind Slabs on West Aspects on Andesite Ridge

Location Name: 
Andesite Ridge
Region: 
Donner Summit Area
Date and time of observation: 
Fri, 01/27/2017 - 12:00
Location Map: 
United States
39° 21' 28.566" N, 120° 21' 57.456" 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: 

East winds had formed stiff wind slabs on leeward westerly aspects in exposed near and above treeline terrain. These wind slabs measured between 6 and 18 inches in depth were between 1 finger and pencil in hardness. They rested on top of cold soft snow that was fist hardness. Skier jumping on wind loaded test slopes could trigger shooting cracks after several jumps. Snowpit data showed that even though triggering these wind slabs may be difficult due to the strength of the slabs, fractures could propagate along the interface between the dense firm slabs and the softer snow below them (video - ECTPV, ECTP2, 2m ECTP 11 x2). The east winds continued to transport snow throughout the day. Easterly and northerly aspects exposed to the wind held firm wind scoured surfaces. In below treeline sheltered areas the snow remained soft and cold on the northerly aspects. Observations in these areas showed signs of settlement and consolidation. On sun exposed below treeline slopes some sun affected snow surfaces had started to form. 

Snowpack photos: 
Snowpit videos (tests, etc): 

2m ECTP on a stiff wind slab on Andesite Peak

Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
Clear
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Air temperature trend: 
Static
Wind Direction: 
East