Calm Winds on Donner Summit

Location Name: 
Donner Summit
Region: 
Donner Summit Area
Date and time of observation: 
Sat, 01/12/2013 - 12:30
Location Map: 
United States
39° 17' 14.838" N, 120° 19' 36.75" W
See map: Google Maps
US


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

No snow transport observed throughout the day with calm to light NE winds.  Previous signs of snow transport and scouring from the NE winds with surface clues and upper exposed N-NE aspects wind affected.  Protected terrain had light unconsolidated snow with no signs of slab formation on any aspect or elevation we encountered.  This unconsolidated snow from the last storm sat on a variety of crusts on E-S-W aspects, on NW-NE aspects the old snow surface was soft.  On East aspects there was a 1'' sun crust that developed before the last storm and the new snow has bonded well to the old sun crust.  CT's did show consistent weakness in the moderate range with Q2 shears below this sun crust on a layer of developing facets.  I only found this situation on East aspects, West aspects had a 4'' sun crust with no weakness noted below or above the crust.

A mostly stable snowpack was observed in this area with no new signs of instability.

Weather Observations
Blowing Snow: 
Cloud Cover: 
Clear
Air temperature: 
Below Freezing
Wind Speed: 
Calm
Precipitation: 
Air temperature trend: 
Static
Wind Direction: 
Northeast
Accumulation rate: 
More detailed information about the weather: 

Clear skies with increasing high clouds by mid afternoon.  NE winds were calm all day.

7800' @ 12:30pm AirTemp -10c, Tsurf -15c, T20 -10c