Observations from Tallac

Location Name: 
Mt Tallac
Region: 
Desolation Wilderness Area (including Emerald Bay)
Date and time of observation: 
Mon, 12/20/2010 - 12:30
Location Map: 
United States
38° 54' 49.356" N, 120° 6' 2.3436" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 

pic 1: Several signs of current instability within new storm snow. This was the only distinct crown observed (natural trigger), but visibility of traditional start zones wasn't very good - I'm guessing there were more crowns we didn't see. There were numerous recent natural sluffs visible. Observations showed easy failures on a low density stellar and needle layer below 15-20cm of higher density clustered stellars at the surface.

pic 2: Large debris pile at about 7000ft appeared to have occured within 24hrs. Avalanche terrain bordered either side of slide path, but path was narrow and deeply channeled, and failed to initiate additional failure - indicating Dec 16th surface hoar likely had previously collapsed. Start zone at 9000ft.

At coordinates entered on map, early December rain crust was probed at 235cm deep. This would put the Dec 16th surface hoar layer at ~200cm deep. Height of snow was greater than 450cm. Informal pit dug to 150cm showed a "rightside up" snowpack with the exception of previously mentioned storm snow weakness just below surface.

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