Wind Slab on Powderhouse

Location Name: 
Powderhouse Peak
Region: 
Luther Pass Area (including Job and Freel)
Date and time of observation: 
Sun, 03/06/2016 - 14:00
Location Map: 
United States
38° 46' 58.6308" N, 119° 58' 41.106" W
See map: Google Maps
US


Red Flags: 
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Terrain Trap
Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 

Approximately 14 inches of new snow at Grass Lake with approximately 20 inches at highest elevations in this area. Wind affected snow on north facing treed slopes noted 300 feet below summit of Powderhouse. No instabilities observed below this point within the treed terrain. Along summit ridgeline wind was moving snow and creating wind slab. Cracks were easily caused by skier activity. On steeper convex rolls these wind slabs could be triggered by a skier or rider.

Photo 1: Short lived graupel event at 2pm. Little accumulation observed.

Photo 2: Strong winds were moving snow and creating wind slab along the summit ridgeline.

Photo 3: These slabs were strong enough to show cracking in response to skier weight.

Photo 4: Small test slope rider triggered wind slab. Inconsequential in this location but would be an issue in bigger terrain. Video shows the triggering of this slide. Results here were consistent with previous observations. 

 

Snowpack photos: 
Snowpit videos (tests, etc): 

Powderhouse Wind Slab 2016.3.6

Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
50% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Strong
Precipitation: 
Snow
Air temperature trend: 
Static
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: