Near surface facets, some surface hoar, and some wind slabs on Silver Peak.

Location Name: 
Silver Peak
Region: 
Cabin Creek, Deep Creek, or Pole Creek Area
Observation Date & Time: 
Tuesday, December 17, 2019 - 11:00
Location: 
39.225640, -120.240020
Is this an Avalanche Observation?: 
No


Conditions Alerts:


Terrain Alerts: 
Slopes Steeper than 30 degrees
Obvious Slide Path
Terrain Matches the Advisory

Observation made by: Forecaster

Tabs

Observation
Description of Snow, Weather, and Avalanche Conditions: 

We toured into Silver Peak today to have a look at rain crusts in the snowpack in the 7,000' to 8,000' range and to see ridgetop wind slabs.

At the surface, a 5 inch layer of near surface facets were prevalent in wind protected open areas below treeline. These weak sugary facets were sitting on top of the Dec 12 rain crust. We got short cracks while breaking trail both within the facet layer and down to the top of the Dec 12 rain crust. With no overlying slab at this time, this was not a current stability issue. This layer is worth monitoring for possible burial and problematic weak layer formation.

Surface hoar up to 10mm in size was observed in large open areas low on the peak. Surface hoar became progressively smaller to absent as we ascended the peak. Surface hoar was absent in any areas that had sufficient tree cover to create a forest canopy.

In the snowpit dug at the noted lat/long (N aspect, 7,500') we identified no current problematic weak layers associated with rain crusts. The near surface facets and surface hoar making up the top 9 inches of the snowpack stood out as the more concerning layer (as a possible future problem).

Upon reaching above treeline terrain near the top of the peak, we encountered hard wind slab up to 1 foot thick. Seeing minor cracking around the thinner edges of this wind slab area caused us to alter our travel plan and take a more conservative route, avoiding the wind slab rather than following our planned route that would have exposed us to it. 

Snowpit or crown profile photo or graph: 
Hide Snowpack Details
Total Snow Depth: 
142cm
Persistent Weak Layers: 
On the surface
Hide Terrain Details
Terrain: elevations: 
Above Treeline
Near Treeline
Below Treeline
Terrain: aspects: 
N
NE
Hide Weather Details
Elevation of Observation: 
7000 - 8000 ft.
Blowing Snow: 
Light
Wind Direction: 
Southwest
Wind Speed: 
Moderate
Sky Cover: 
Overcast - Cloudy - 8/8 covered
Precipitation: 
None
Air temperature: 
Above Freezing
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