Isolated wind slabs and buried NSFs at Grouse Rocks.

Location Name: 
Grouse Rocks
Region: 
Blackwood Canyon or Ward Canyon Area
Date and time of observation: 
Sat, 02/28/2015 - 14:30
Location Map: 
United States
39° 8' 6.972" N, 120° 14' 30.048" 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 ranged from 45 cm at 7,100' up to 62 cm at 8,200'. Small natural avalanches (more info in separate observation) had occurred both at ridge level and low on the slope in open areas below treeline. New snow slab had little cohesion with deep ski pen. ECTN and PST SF at 50% cut length results on buried near surface facets in testpit at noted lat/long (N aspect, 8,200', 30 deg slope angle). Some concern exists for increasing instability over the coming days at the base of the storm snow slab as settlement and bonding increases the strength of the slab and more stress is concentrated at the relatively weak old near surface facets at the base of the storm snow.

Photo: Skier triggered shooting crack 20' long in wind slab along summit ridge. Photo heavily contrasted due to low light conditions.

Snowpack photos: 
Snowpit videos (tests, etc): 

20150228 ECTN Grouse Rocks, CA

20150228 PST 50/100 SF on NSF down 62cm.

Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Light
Precipitation: 
Snow
Air temperature trend: 
Static
Wind Direction: 
West
Accumulation rate: 
Less than 1 in. per hour