Storm Slabs and Wind Slabs on Andesite Peak

Location Name: 
Andesite Peak
Region: 
Donner Summit Area
Date and time of avalanche (best estimate if unknown): 
Thu, 02/02/2017 - 11:00
Location Map: 
United States
39° 20' 59.2656" N, 120° 21' 55.0368" 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
Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
Dry
Slab
Trigger type: 
Skier
More detailed information about the avalanche: 

Small storm slabs and wind slabs forming on Andesite Peak this morning.  Intentionally triggered storm slab avalanche (D1) on steep NE aspect at 7900'.  Storm slab was 4'' deep and was failing within the recent storm snow just above the old snow/new snow interface.  Propagation was wide with an upside down storm snow structure with heavier snow on top of less dense snow from warming temperatures and rising snow levels through this morning.  Small wind slabs were also able to be intentionally triggered.  Wind slabs were 4-8'' and were failing where density went from 4F wind slab down to F hard snow.  Temperatures were warming throughout the morning with snow turning to rain at the trailhead by mid day.

We looked at many different areas for recently buried surface hoar and could not find any evidence in this area. 

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