Spring Conditions on Castle Peak

Location Name: 
Castle Peak
Region: 
Donner Summit Area
Date and time of observation: 
Wed, 11/22/2017 - 10:30
Location Map: 
United States
39° 21' 53.856" N, 120° 21' 30.96" W
See map: Google Maps
US


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

Evidence of rain on snow existed up to the summit of Castle Peak. A rain crust that varied in thickness and supportability existed on all the shaded aspects. In some areas, this crust was firm and icy and in others it was breakable. Below this crust, a well-bonded moist snowpack existed to the ground. On the sun-exposed SW-S-SE aspects enough melting occurred for spring-like conditions to form with 2-3 inches of soft wet corn snow on top of a supportable still frozen layer.  In some areas, small pinwheels and roller balls started occurring around 11 am. These small signs of loose wet instabilities were the only signs of instability our observations revealed today. 

Photo 1: Icy crusts on the northerly aspects that ranged from breakable to supportable.

Photo 2: Breakable rain crust and rain runnels in a meadow at 7800 ft. 

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Calm
Air temperature trend: 
Warming