Wind Slabs on Andesite Ridge

Location Name: 
Andesite Ridge
Region: 
Donner Summit Area
Date and time of observation: 
Fri, 03/26/2010 - 15:00
Location Map: 
United States
39° 21' 5.2416" N, 120° 22' 0.5844" 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
Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

Photo 1: Graupel at 252 cm down in the snowpack. Snowpit tests did not produce any results on this layer (most likely due to the strong snow above it protecting it from the force applied on the snow surface).

Photo 2: Skier triggerred shooting crack on a N facing, wind loaded slope near the ridgeline on Andesite Ridge.

Photo 3: 1.5 ft deep wind slab just below the shooting crack in the previous photo. This slab only extended down slope about 5-10 ft from the ridge. The failure layer is the graupel layer at 274 cm in the snowpack.

Video: West winds loading snow onto the NE-N aspects.

Wind transport near the top of the ridge continued to build wind slabs on the N-NE aspects during the day today. Some of the most wind-loaded areas remained sensitive to skier-triggereing (photos). SE-E aspects starting to warm up during the day. Some small skier triggered pinwheels and wet sluffs occurred on these more sun exposed aspects.

 

 

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Snowpit videos (tests, etc): 

Wind transport on Andesite Ridge

Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Moderate
Precipitation: 
Air temperature trend: 
Static
Wind Direction: 
West
Accumulation rate: 
More detailed information about the weather: