Small wind slabs on Silver Peak

Location Name: 
Silver Peak
Region: 
Cabin Creek, Deep Creek, or Pole Creek Area
Date and time of observation: 
Sat, 12/19/2015 - 11:35
Location Map: 
United States
39° 13' 24.456" N, 120° 14' 33.954" W
See map: Google Maps
US


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

New snow amounts in this area were around 15 cm. Evidence of instability in this area today was in the form of small wind slabs in areas of direct wind loading both near treeline and above treeline. Stepping on wind pillows along the E ridge of Silver Pk produced cracks up to 2 m long. Wind slabs sections that moved down slope were generally 10 to 20 cm thick, failing within the wind deposited storm snow. Occasional cracking was noted to occur deeper going down to the old/new interface up to 30 to 40 cm down in the most wind loaded areas. In these areas with deeper cracking, actual slab failure was still occurring higher within recent storm snow.

A test pit in fairly SW wind sheltered near treeline terrain along the E ridge of Silver Pk on a N aspect at about 7,900' produced no problematic failures in snowpit tests. With the wind protection, surface wind slab was absent. No indications of persistent weak layers were observed around the Dec 10 or Dec 13 crusts at the snowpit location. This absence of a pwl has been the snowpack history in this specific location.

Snowpack 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: 
Static
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Off and on winds ranging between periods of calm and moderate speed SW.