Loose Wet and Cornice Collapse on Castle Peak

Location Name: 
Castle Peak
Region: 
Donner Summit Area
Date and time of observation: 
Sun, 04/23/2017 - 14:00
Location Map: 
United States
39° 21' 34.5888" N, 120° 20' 28.0572" W
US


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Rapid warming

Observation made by: Guide at Tahoe Mountain School
Snowpit Observations
More detailed information about the snowpack: 

Marginal overnight refreeze at best with mostly sunny skies by mid morning and strong SW winds above 8000'.  Some large previous loose wet avalanches observed on the North side of Castle Peak.  Through most of the morning hours ski pen was acceptable along the south ridge with boot pen of ankle to shin deep.  The north side had slightly firmer conditions with areas of breakable crusts.  By early to mid afternoon, ski supportability declined at 8500' and below to ankle and shin deep.  Loose wet avalanches were easily skier triggered on slopes steeper than 30 degrees.  A natural cornice collapse was observed mid afternoon off the south ridge on an E aspect at 8000'.   

Snowpack photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Strong
Precipitation: 
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
More detailed information about the weather: