Dense snow at Carson Pass

Location Name: 
Frog Lake Ridge
Carson Pass Area
Date and time of observation: 
Tue, 12/22/2015 - 10:00
Location Map: 
United States
38° 41' 30.2172" N, 119° 59' 15.558" W

Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Obvious avalanche path
Terrain Trap

Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 

Pic 1: A thin rain crust observed on surface today at Carson Pass

Pic 2: Although settlement cracks were observed around trees right next to this test slope, storm snow instability still present down 20cm. Note this test slope is steep, convex, and unsupported. Similar results were not observed on several slopes with better compressive support.

Pic 3: Widespread cracking in start zones along Frog Lake Ridge. It's possible that a combo of dense slab and slope shapes with compressive support prevented these areas from avalanching.

Pic 4 (also submitted as avalanche obs): 2 adjacent natural avalanches observed along Frog Lake Ridge in windloaded, steep terrain. Too much hangfire for proper crown profiles, but adjacent safe slope showed 12/13 crust at about the same height (100cm from the surface) as crowns, with weak layer observed just below crust. 

Although a rain crust was present at the surface, wind was still blowing snow and accumulating in deposition zones. Most cracks and downslope debris remained sharp and fresh looking, but wind transported snow had already begun filling-in start zones at 2 observed avalanches.

Snowpack photos: 
Weather Observations
Blowing Snow: 
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Mixed rain and snow
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: