Snowpack observations from Andesite Ridge

Location Name: 
Andesite Ridge
Donner Summit Area
Date and time of observation: 
Thu, 01/25/2018 - 12:00
Location Map: 
United States
39° 21' 1.1124" N, 120° 21' 48.1068" W

Red Flags: 
Recent loading by new snow, wind, or rain
Obvious avalanche path

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

We toured the Andesite Ridge avalanche terrain from the far south end up to the summit, examining NE-E aspects along the way. New snow amounts in this areas were 12 to 15 inches. Finding evidence of instability proved difficult despite the new snow load. One big caveat was that we did not encounter any areas where we could find buried surface hoar. This was the main stability question remaining unanswered from this morning's observations in this area.

Otherwise, we found widespread recently formed wind slabs near and above treeline that were unreactive. Very minor cracking up to 3 feet long was skier triggered in a single area. All other wind slabs tested in numerous areas did not fail. Storm slab cracking of the top 6 inches of the storm snow was prominent below treeline. This failure layer was easily identified in snowpit tests at the noted lat/long (7,920', NE aspect, below treeline, at top of known avalanche path). These same tests indicated that propagation along this storm slab instability or any of the other relative weak layers in the pit was unlikely.  We looked up to one foot below the old/new snow interface at which point the lower snowpack changed to very strong rounded polycrystals with uniform hardness probed out the bottom 45 cm of the pit.

Snowpack photos: 
Weather Observations
Blowing Snow: 
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Andesite Ridge was under full cloud cover with snowfall more often than not during the morning hours.