Observations from Tallac

Location Name: 
Tallac
Region: 
Desolation Wilderness Area (including Emerald Bay)
Date and time of observation: 
Mon, 03/11/2013 - 12:00
Location Map: 
United States
38° 54' 56.2392" N, 120° 6' 2.8692" W
See map: Google Maps
US


Red Flags: 
Rapid warming
Obvious avalanche path
Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 

Facet/crust combo was found on N, NE, E aspects from 7,000ft to 9,000ft. Crust was observed to be weakest between 8,500ft and 9,000ft. Above 9,000ft, a previous windslab which is now rounded added strength just above the crust.

Video 1: Low elevation, mostly E aspect slope. Although facets were large and sugary, vertical percolation tubes interrupted faceted layers.

Video 2 and 3: Just uphill from video 1, and more N aspect. No percolation tubes observed. 2x ECTN on facets above the crust, and 2x PST 30/100 (end) below the crust.

Video 4: Just below Corkscrew ridgeline, at 9,100ft on NE aspect. 2x PST 30/150 on facets below crust.

Very warm day. Even steep, shaded aspects underwent a slight melt phase at the surface. Signs of wet instabilities limited to intentional roller ball activity. Several previous loose wet slides observed on steep slopes with strong solar input and exposed rocks.

Snowpit videos (tests, etc): 

2013.03.11 inconsistent results due to perc tubes

2013.03.11 2x ECTN on facets above crust

2013.03.11 2x PST 30/100 (end) down 55cm

2013.03.11 2xPST 30/150 (end) down 85cm

Weather Observations
Blowing Snow: 
No
Cloud Cover: 
Clear
Air temperature: 
Above Freezing
Wind Speed: 
Calm
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
Accumulation rate: 
None
More detailed information about the weather: 

Few, thin high clouds by mid afternoon.