Warm and calm day at Carson Pass

Location Name: 
Frog Lake Ridge
Region: 
Carson Pass Area
Date and time of observation: 
Mon, 12/18/2017 - 15:00
Location Map: 
United States
38° 41' 15.7956" N, 119° 59' 9.6864" 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: 

Pic 1: A fistfull of near surface facets, the predominant surface form on shaded slopes and indirect sunny slopes.

Pic 2: Meiss approach and Red Lake Peak car shuttle approach both looking pretty grim. Although there's still plenty of snow along Frog Lake Ridge, the trail is well traveled and firm enough for travel on foot. Ice skaters today on Winnemucca Lake, Frog Lake, and Red Lake.

Full sunny features had 10cm of wet, corn snow.

Indirect or low angle sunny slopes had a very thin 1mm crust forming at the surface, with near surface facets right underneath. Temperature gradient measured with IR thermometer showed surface temps of -1.0c and -5.0c just 1cm down.  

Full shaded slopes had a variety of surface grain types due to recent wind events, but the predominant grain type observed was facets. Temperature gradient measured with IR thermometer showed surface temps of -17.0c and -12.0c just 1cm down.  I performed two ECTs at the same location as on 12/6 and today, the slab above the weak layer was noticeably more faceted than on 12/6, and the facets comprising the weak layer appeared to have gained strength. Today, neither ECT propagated.  Upon levering the columns after the ECTs, they broke at the same layer as on 12/6 but with very poor shear quality (Q3) compared to 12/6.

Snowpack photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Calm
Precipitation: 
None
Air temperature trend: 
Warming
Accumulation rate: 
None