Buried Surface Hoar, Wind and Snow on Andesite

Location Name: 
Andesite Peak
Region: 
Donner Summit Area
Date and time of observation: 
Wed, 01/13/2016 - 10:30
Location Map: 
United States
39° 20' 59.1828" N, 120° 21' 45.0108" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Obvious avalanche path
Terrain Trap
Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

4-6'' of new heavy dense snow had accumulated in the Andesite Ridge area by late morning.  Gale force winds and heavy snow made visibility challenging.  2 snowpit locations below treeline at 7700-7800' showed that another layer of surface hoar has been buried under the new storm snow-the Jan 13 buried surface hoar layer.  This layer was showing ECTN's in protected treed terrain and no results were noted below on the 1/9 and 1/5 buried surface hoar layers.  In more open below treeline terrain that was receiving some wind loading results were different.  Consistent ECTP were occurring on the 1/13 layer and occasionally stepping down to what appeared to be the 1/9 buried surface hoar layer.

Small cracking was common below treeline and long shooting cracks were occurring near and above treeline. 

Photo #1:  ECTP-12.  4'' of new snow failing at the old snow/new snow interface.  3-4mm surface hoar.

Photo #2-3:  Large shooting cracks

 

Snowpack photos: 
Snowpit videos (tests, etc): 

IMG 1577

Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Gale Force
Precipitation: 
Snow
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
Greater than 1 in. per hour