Andesite Peak Snowpack Observations

Location Name: 
Andesite Peak
Region: 
Donner Summit Area
Date and time of observation: 
Sat, 12/24/2016 - 12:00
Location Map: 
United States
39° 21' 3.7908" N, 120° 21' 59.5188" W
US


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain

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

Up to 16'' of storm snow at this location.  Most of this snow was unconsolidated with little evidence of any recent wind in this area.  Several ski kicks on small test slopes near treeline and in open areas near the peak showed only loose dry sluffing running downslope with no slab formation observed.  Snowpack tests done at the peak on E aspect at 8200' showed little to no results. 

Observations below treeline in protected areas showed different results.  Some cracking and collapsing around skis was noted.  A whumpf was felt on a West aspect at 8000' on the back side of the peak in treed terrain.  Snowpack observations and tests showed some weakness at the new snow/old snow interface and the near crust facets above the 12/15 rain crust were present and loose.  2x ECT's had no results but PST's indicated that propagation could occur on this NCF weak layer.  Very close to my test pit was a small skier triggered storm slab avalanche-see avalanche observation.  The recent storm snow is mostly unconsolidated and not very cohesive.  There is concern that as this layer settles and gains strength, it may become a stronger slab and may be more easily triggered in areas where the NCF's exist above the 12/15 rain crust.   Areas on the Sierra Crest where this combination is thought to exist are shaded and protected below treeline terrain, below 9000', that had facets develop on top of the 12/15 rain crust before this recent storm snow.
 

Snowpack photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
50% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Calm
Precipitation: 
Air temperature trend: 
Static
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: 

Light snow in the morning with fog around pass elevation.  Up towards the peak, sun was out with calm conditions and partly cloudy skies.