Continued Reactive Surface Hoar in Pole Creek

Location Name: 
Silver Peak
Region: 
Cabin Creek, Deep Creek, or Pole Creek Area
Date and time of observation: 
Mon, 01/18/2016 - 12:00
Location Map: 
United States
39° 13' 34.248" N, 120° 14' 22.056" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

Investigated another natural avalanche caused by buried surface hoar.  Avalanche thought to have occurred late Saturday or sometime Sunday and could have been related to a rain event.   The bed surface and debris was covered by approximately 4-6'' of new snow.  Large open area below treeline terrain with an average slope angle of 30 degrees and slope angle at crown at 34 degrees.  Avalanche was 200' wide and ran downslope for 150' with debris into the trees below.  Consistent snowpack tests at crown revealed that buried surface hoar was the failure and that it is still reactive in this area.  

New snow was in the 15-20cm range with some previous wind loading occurring over night.  Signs of wind scouring along the Sierra Crest and swirling winds throughout this area.  No other signs of instabilities existed in this area.  Small roller ball activity occurred off of rocks on the solar aspects.

Photos:  Natural avalanche caused by buried surface hoar-covered by last nights storm snow.  3-7mm surface hoar grains.

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Light
Precipitation: 
None
Air temperature trend: 
Static
Wind Direction: 
Southwest