Frozen Crusts and Soft Melt Freeze Snow near Bear Valley

Location Name: 
Underwood
Region: 
Bear Valley Area
Date and time of observation: 
Fri, 03/07/2014 - 16:00
Location Map: 
United States
38° 30' 19.1376" N, 120° 0' 10.0944" W
See map: Google Maps
US


Red Flags: 
Rapid warming
Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

A few inches of soft melt/freeze snow existed above a still frozen crust on the SW and W aspects between 3 and 5 pm from 7400 ft to 8500 ft on the flanks on Poison Peak. Reports from earlier in the day indicated that the S-SE-E aspects had softened much earlier and that deeper unsupportable wet  snow existed on the S aspects during the hottest part of the day. The E-SE-S aspects started to refreeze by late afternoon.

On the northerly aspects and on shaded areas on other aspects the surface remained frozen throughout the day. A natural cornice collapse did occur on a wind loaded N-NE facing slope near 8600 ft near Underwood Bowl (see photo 5). This cornice collapse did not trigger any signs of slab instability on the wind loaded slope. Snowpit tests and data on a similar wind loaded test slope showed a strong and stable snowpack below a firm, frozen rain crust.

Photo 1: Runnels indicating good drainage on a SE aspect at 7800 ft.

Photo 2: 2 inches of soft melt freeze snow on a W aspect at 4:30pm at 8200 ft.

Photo 3: Frozen rain crust at 8600 ft.

Photo 4: Rain crust and graupel sandwich on a NE aspect at 8400 ft.

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
Clear
Air temperature: 
Above Freezing
Wind Speed: 
Moderate
Precipitation: 
None
Air temperature trend: 
Cooling
Wind Direction: 
Northeast
Accumulation rate: 
None
More detailed information about the weather: 

Temps started cooling below freezing by 5 pm above 8200 ft.