Cracking wind slabs and weak cornices on Lincoln Ridge.

Location Name: 
Lincoln Ridge
Region: 
Yuba Pass Area
Date and time of observation: 
Wed, 02/12/2014 - 13:00
Location Map: 
United States
39° 35' 27.0024" N, 120° 29' 25.8144" 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: 

Significant amounts of wind transport, wind loading, and subsequent slab formation were observed in near treeline and above treeline terrain on NE aspects above 7,700' in this area today. Small wind slabs up to 20 cm thick cracked easily when loaded by the weight of a skier. Small cornice features also collapsed easily in response to the weight of a skier. Shooting cracks up to 6 m long were observed as wind slabs and small cornices failed. Wind slabs were pencil hard and failed on the top of a 4 cm layer of fist hard DFs sandwiched between the bottom of the wind slab and the top of the Feb 9 rain crust. Spot probing along the NE side of the ridge in areas of limited previous wind loading revealed an HS of 100 to 110 cm. At the surface was 4 to 10 cm of recent storm snow on the surface. Below that was the 10 cm thick Feb 9 rain crust on top of fairly uniform increasing density snow down to the ground.

Photos 1 & 2: Wind transport on Lincoln Ridge

Photo 2: Skier cracked wind slab

Photo 3: Skier cracked cornice

Snowpack photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Strong
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
Southwest