Deep Persistent Weak Layer on Tamarack Peak

Location Name: 
Tamarack Peak
Region: 
Mount Rose Area
Date and time of observation: 
Wed, 12/23/2015 - 11:30
Location Map: 
United States
39° 18' 47.268" N, 119° 54' 21.636" W
See map: Google Maps
US


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

Observations from the Tamarack Peak area today showed several past slab avalanches thought to be from sometime on Tuesday.  Most of these avalanches appeared to be small wind slabs but some were far away and couldn't be confirmed.  We also examined the 12/10 rain crust and the weak faceted snow below.  The 12/10 RC now sits around 4-5' below snow surface.  The faceted snow below the rain crust was easily found on most NW-N-NE terrain and was 2-6mm in size.  Areas above treeline where heavy wind scouring occurred early season from NE winds  the snowpack is closer to 3' deep.  

A PST test on the basal facets below the 12/10 rain crust showed that if someone could trigger this weak layer propagation would be possible. See attached video.

10:30, 8993', North aspect, 22 degree slope.  PST 65/150 END down 150cm on basal facets below 12/10 rain crust.  ECTN-22 @ 121cm up from ground.  D-ECTP-22 on basal facets below 12/10 rain crust. 

Photo#1: Facets at teh base of the snowpack

Photo#2:  Settlement cones around trees.

Snowpack photos: 
Snowpit videos (tests, etc): 

PST 65|150 END on Tamarack Peak

Weather Observations
Blowing Snow: 
No
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Precipitation: 
None
Air temperature trend: 
Static
Wind Direction: 
Southwest