Cracking on Donner Peak

Location Name: 
Donner Peak
Region: 
Donner Summit Area
Date and time of observation: 
Fri, 02/03/2017 - 13:00
Location Map: 
United States
39° 18' 36.1044" N, 120° 19' 6.4056" 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: 

Several density changes existed in the top 12 to 16 inches of the snowpack resulting from changes during the storm over the last 24 hrs. A rain crust existed about 10 to 14 inches down in the snowpack up to about 8000 ft. Heavy dense snow existed on top of lighter snow above this rain crust. Hand pits and snowpit tests showed weakness at this interface, but they also indicated that it may be difficult for a fracture to propagate along this weakness. In near and above treeline terrain where wind loading had and was continuing to occur, ski kicks triggered cracking of cornices above wind loaded slopes and some human triggered cracking did occur on wind loaded test slopes. If the test slope was undercut, ski cuts on the slope would cause wind slab failures. 

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

Steady winds and dense snow all afternoon.