Snowpit and observations from Castle Peak

Location Name: 
Castle Peak
Region: 
Donner Summit Area
Date and time of observation: 
Wed, 03/14/2012 - 12:35
Location Map: 
United States
39° 21' 54.432" N, 120° 21' 41.796" W
See map: Google Maps
US


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: 

Evidence of instability was limited to the top portion of the storm snow in this area. Several density inversions were very apparent within the storm snow in wind protected areas. In wind loaded areas such as at the snowpit location, these density inversions were much more subtle. Cracking was limited to the top surface slab no more than 20-30cm deep.

Photo - Pit wall with only subtle density inversions within the storm snow. The persistent weak layer / facet layer just below mid height in the overall snowpack is clearly visible at the base of the pit. It is below the depth appropriate to test with the ECT and was unreactive in the PST, however the column did drop about 4cm vertically when failure occurred near the end of the PST cut.

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Strong
Precipitation: 
Snow
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Snow level had risen to around 6,500' on Donner Summit at 2:15 pm.