Shooting Cracks and Small Wind Slabs on Andesite Ridge

Location Name: 
Andesite Ridge
Region: 
Donner Summit Area
Date and time of observation: 
Mon, 03/23/2015 - 12:30
Location Map: 
United States
39° 20' 58.578" N, 120° 21' 55.656" W
See map: Google Maps
US


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

3 to 6 inches of new snow existed in areas above 7500 ft. on Andesite Ridge today. In areas where snow cover previously existed, the new snow fell on top of warm melt-freeze crusts that are now starting to refreeze. Hand pits and test pits indicated that the new snow seemed to be forming good bonds with these old snow surfaces. However, the layer of storm snow at the base of the new snow is lighter and weaker than the snow above it. Skier triggered shooting cracks several feet in length did occur on wind loaded test slopes in near and above treeline terrain. The wind slabs resting above the softer weaker layer of snow at the base of the new snow measured between 8 and 16 inches. Below 8000 ft. the snowpack started warming up quickly this afternoon and some small skier triggered wet snow sluffs did start to occur on steep test slopes.

In areas where previous snow cover did not exist, the new snow barely covered the dirt and obstacles.

Photo 1: Barely covered ground @ 7600 ft on an E aspect

Photo 2: Skier triggered shooting crack that failed on the softer layer of snow at the base of the new snow. Photo taken at the location attached to this observation. NE aspect @ 8100 ft.

Photo 3: Larger cracking on a previously undercut wind loaded test slope @ 8140 ft. on a NE aspect.

Photo 4: Loose wet snow sluff on a NE aspect @ 7800 ft.

Video: ECTP8 on the softer layer of snow at the base of the storm snow on a wind loaded test slope @ 8100 ft. on a NE aspect.

Snowpack photos: 
Snowpit videos (tests, etc): 

ECTP on Andesite Ridge

Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Moderate
Precipitation: 
Snow
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Warming temperatures during the day.