Small wind slabs and storm slabs on Castle Peak.

Location Name: 
Castle Peak
Donner Summit Area
Date and time of observation: 
Sun, 11/15/2015 - 14:00
Location Map: 
United States
39° 21' 54.8748" N, 120° 21' 35.4168" W

Red Flags: 
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain

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

New snow amounts were in the 10 to 12 cm range in this area between 12:30 and 3pm. Snowfall intensity was noted to increase around 2:30 pm. Around 8,300', wind loaded areas near treeline held wind slabs up to 15 cm deep that cracked easily under the weight of a skier (photo 1). These wind slabs did not extend very far down slope. Open areas below treeline with well developed near surface facets at and below the old/new snow interface displayed some cracking and failure 30 cm deep into the snowpack while skinning (photo 2). Evidence such as this of storm slabs existed in isolated areas where near surface facets were well developed.

Photo 1: Wind slab cracking, E aspect, 8,300', near treeline terrain.

Photo 2: Cracking from the snow surface 30 cm down into older near surface facets. NW aspect, 8,160'.

Snowpack photos: 
Weather Observations
Blowing Snow: 
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
Less than 1 in. per hour