Donner Summit Observations

Location Name: 
Mt. Judah
Region: 
Donner Summit Area
Date and time of observation: 
Sun, 03/27/2011 - 12:00
Location Map: 
United States
39° 18' 12.1968" N, 120° 19' 3.0684" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 

Natural avalanche activity observed in Negro Canyon, Donner Pass area-backside of Black Wall, and East Bowl of Mt. Judah.  Most of this activity was thought to be from late yesterday or early morning hours.  Visibility was very limited all day at the upper elevations with snow falling throughout the day with strong to extreme SW winds.  The upper snowpack was very wind effected with ski pen of only 0-4'' giving the snow conditions a heavy dense wind buff feeling.  There was a density change down 2' that could be felt easily with a ski pole where lighter snow is below the heavier denser wind effected snow.  Several hand pits, ski cuts, cornice drops all showed no signs of propagation on any of the upper snowpack layers.  There was some small cracking associated with a newly forming wind slab in isolated areas that was up to 4'' deep.    

Snowpit videos (tests, etc): 

donnersummit2011 3 27 033

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: 

Sky 100% covered by clouds for the whole day.  Light snowfall with continuous strong to extreme SW winds.  Snow crystal type varied throughout the day with plently of graupel and riming occuring which gave it that wet/damp feeling.