Rain on Snow and Large Pinwheels on Barker Pass

Location Name: 
Barker Pass
Blackwood Canyon or Ward Canyon Area
Date and time of observation: 
Thu, 03/10/2016 - 12:00
Location Map: 
United States
39° 4' 26.7708" N, 120° 13' 50.9232" W

Red Flags: 
Recent loading by new snow, wind, or rain
Rapid warming

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

Rain on snow created a layer of wet snow 5 to 15 cm deep on all aspects in the Barker Pass area. Large pinwheels occurred due to snowmobile cuts and in response to rolling small snowballs down the hill. Some of these pinwheels measured up to 1.5 m in diameter. Other than these loose wet snow instabilities no other signs of instability were observed up to 7800 ft. today. Snowpit tests on a wind loaded NE facing slope at 7700 ft. (39.074103, -120.230812) showed drier (but still moist) snow under the saturated wet surface wet snow. ECT's did show some fractures in various density changes within the recent snow, but none of these fractures propagated across the column.

Photo 1: Large human triggered pinwheel on a steep N facing slope at 39.081033, -120.210256. 

Photo 2: Rain runnels on the snow surface on at ~7200 ft. at 39.07785,-120.2254556

Snowpack photos: 
Weather Observations
Blowing Snow: 
Cloud Cover: 
100% 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: 

Snow level was hovering between 7600 ft. and 7800 ft during the day and precipitation was a mix of rain and snow at these elevations and full rain below 7600 ft.