Propagation on 12/15 Facets

Location Name: 
Andesite Peak
Region: 
Donner Summit Area
Date and time of observation: 
Fri, 01/06/2017 - 14:15
Location Map: 
United States
39° 21' 24.624" N, 120° 21' 54.612" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

Cold clear weather overnight left softer less cohesive snow on the surface today. The NE winds during the night had scoured some snow away from E-NE slopes near the ridge on Andesite. Oven to refrigerator sized cornice blocks dropped onto wind loaded test slopes did not trigger any cracking nor did ski kicks on those slopes. Settlement cracks and cones near trees did indicate that the upper snowpack continues to consolidate; however,  snowpit data from an E aspect near an avalanche that likely occurred on Wed (photo here) showed that weak snow (facets) still exists near the 12/15 rain crust and that fractures can travel through this weak snow. This persistent weak layer was buried 130 to 165 cm below the surface in this area. Probing indicated that it still exists on the E-NE-N-NW aspects and that it may still exist on some W aspects as well. 

Photo: Settlement crack and cone near a tree

Video: PST 45/165 END on the facets above the 12/15 rain crust. 

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Snowpit videos (tests, etc): 

PST on Andesite Ridge

Weather Observations
Blowing Snow: 
No
Cloud Cover: 
50% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Light
Precipitation: 
Air temperature trend: 
Static
Wind Direction: 
Southwest
Accumulation rate: 
More detailed information about the weather: 

Increasing clouds during the afternoon.