New wind slabs in the Mt. Rose backcountry

Location Name: 
Prolateriate
Region: 
Mount Rose Area
Date and time of observation: 
Tue, 02/22/2011 - 15:15
Location Map: 
United States
39° 19' 0.0696" N, 119° 55' 4.3788" 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: 

West to southwest winds transported enough snow to form new, shallow, stiff wind slabs on top of the previous wind slabs in the Mt. Rose backcountry today. Any of the near and above treeline leeward slopes, had some wind affect and and wind slabs ranging from 3-12 inches in thickness. Some of the slabs extended several 10's of ft down slope and others were limited to the the areas just below the ridgetops. Stability tests on these slabs showed that fractures can occur at the base of the new wind slabs as well as at the interface between the softer snow below all of the wind slabs formed over the last few days.

In sheltered areas soft snow existed on the surface and obsevations showed good settlement and consolidation. On the sun-exposed aspects a thin breakable sun crust had formed.

Photo 1: A kick with my ski triggered this 12 inch thick wind slab on an east facing test slope near 9700 ft.

Photo 2: Skier triggered shooting crack on a lower angle, wind-loaded, N-NE facing slope at 9500 ft.

Video: Wind transport and stability tests on the the Prolateriate.

Snowpit or crown profile photo or graph: 
Snowpit videos (tests, etc): 

Tamarack ob

Weather Observations
Blowing Snow: 
Yes
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Precipitation: 
None
Air temperature trend: 
Cooling
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Stronger than forecast winds transported snow in near and above treeline terrain all day.