Wind Slabs and Facets on Judah

Location Name: 
Wildflower Ridge
Region: 
Donner Summit Area
Date and time of observation: 
Wed, 11/25/2015 - 13:45
Location Map: 
United States
39° 18' 27.8316" N, 120° 19' 7.7952" 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: 

Observations in non wind affected areas showed that the new snow remained very soft and had few slab characteristics. Tests in these areas and ski cuts on steep and sheltered slopes only resulted in small dry snow sluffs. In wind loaded areas wind slabs up to 3 ft in depth existed. Ski cuts showed that these wind slabs have gotten slightly more difficult to trigger, but adding a person's weight to a wind loaded test slope would still trigger wind slabs on many of the test slopes today. In areas where a hard slab existed under the new wind slabs, additional jumping on test slopes would cause a failure in the facets under the hard slabs. Stepping off of my skis to dig a test pit on a wind loaded NE facing test slope at 7760 ft. also triggered a large whumph as the facets in the bottom part of the snowpack collapsed. Extended Column Tests at that location (marked on the observation map) showed that if that lower weak layer does break fractures can propagate along it. 

Photo 1: Ski width wide loose dry sluff.

Photo 2 and 3: Skier triggered cracking and wind slab failure on a NE facing wind loaded test slope at 7760 ft. 

Photo 3. Coverage on the upper bowls of Mt. Judah. Numerous barley covered rocks and other obstacles still exist. 

Snowpack photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Light
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
West
Accumulation rate: 
None
More detailed information about the weather: