Donner Summit Observations

Location Name: 
Donner Summit
Region: 
Donner Summit Area
Date and time of observation: 
Tue, 12/29/2009 - 10:00
Location Map: 
United States
39° 17' 38.3604" N, 120° 19' 3.7812" W
US


Red Flags: 

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

Observations from Mt. Judah, Coldstream Canyon, East face of Mt. Lincoln and the Sierra Crest.  The last storm ended sometime in the early morning hours depositing 2-6'' of new snow in this area.  Skies cleared early in the morning hours with very calm wind and widespread 1-2 mm surface hoar developed by10am in the morning but was not seen in the afternoon, must have been destroyed by the sun and or wind.  The new snow bonded well to the old snow surface which was mostly a supportable crust on E-S-W aspects and unconsolidated snow on NE-NW.  I had minor sluffing on the new snow/old snow interface in steeper N facing terrain other than that no cracking/shooting cracks noted on any aspect or elevation.  There is plenty of new snow readily available for transport and by the early afternoon the moderate SW winds were moving snow on the higher peaks and ridges.  Expecting these wind slabs on NW-E aspects to continue to develop over night with the additional 1’ of new snow forecasted with the strong SW winds.     

 

 

Any other comments about the observation or links to outside pages that have more info on the observation: 

 

Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Precipitation: 
None
Air temperature trend: 
Cooling
Wind Direction: 
Southwest
Accumulation rate: 
More detailed information about the weather: