Soft slab instability in Deep Creek

Location Name: 
Deep Creek
Region: 
Cabin Creek, Deep Creek, or Pole Creek Area
Date and time of observation: 
Mon, 02/27/2012 - 13:00
Location Map: 
United States
39° 14' 43.188" N, 120° 14' 20.112" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
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: 

Rapid new snow loading with widespread instability occurring within the new snow in all areas on NW-N-NE aspects traveled near treeline and below treeline. Snowpack failure was occurring 3 cm above the old/new snow interface on a thin layer of lightly rimed new snow grains. Additional skier triggered cracking was widespread on test slopes steeper than 30 degrees (photo). Small skier triggered slab avalanches and loose snow avalanches occurred on slopes steeper then 35 degrees. No evidence of instability was observed on E aspects, but bonding at the old/new snow interface was poor. Better bonding of storm snow to the old snow surface was observed on NW-N-NE aspects.

The new snow is very low density and at the time observation had not overload the persistent crust/facet weak layer below the old/new snow interface.

 

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Calm
Precipitation: 
Snow
Air temperature trend: 
Static
Wind Direction: 
Accumulation rate: 
Greater than 1 in. per hour
More detailed information about the weather: 

Snowfall rates at 2+ inches per hour for most of the day.