Fragile cornice, unreactive wind slab, and 1.5 inches of new snow on Lincoln Ridge.

Location Name: 
Lincoln Ridge
Region: 
Yuba Pass Area
Observation Date & Time: 
Saturday, January 4, 2020 - 12:00
Location: 
39.593740, -120.492855
See map: CalTopo
Is this an Avalanche Observation?: 
No
Observation made by: Forecaster

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Observation
Description of Snow, Weather, and Avalanche Conditions: 

Went up to Yuba Pass/Lincoln Ridge for snowpack mapping today. New snow from this morning's brief snowfall event was about 1.5 inches. This was just enough to bury the thin weak rain crust from the Jan 1 rain event, now to be referred to as the Jan 4 rain crust. This new snow was just enough to refresh the snowmobiling/skiing conditions to provide decent quality riding below treeline.

Fragile new cornices were observed along Lincoln Ridge from the wind and new snow this morning (photo). On the slopes below these cornices, 3 to 4 inch thick 1 F hard wind slabs were present but unreactive. I was not able to create any cracking from slope cuts or from dropping cornice chunks onto these wind slabs.

A snowpit dug at the noted lat/long (N aspect, near treeline, 7,480') showed a four foot deep, right side up snowpack without any indications of problematic weak layers.

Fragile cornice with unreactive 4 inch thick wind slab below.
Fragile cornice with unreactive 4 inch thick wind slab below.
Snowpit or crown profile photo or graph: 
Hide Snowpack Details
Total Snow Depth: 
125cm
Persistent Weak Layers: 
Not present
Hide Terrain Details
Terrain: elevations: 
Near Treeline
Below Treeline
Terrain: aspects: 
N
NE
Hide Weather Details
Elevation of Observation: 
6000-7000 ft.
7000 - 8000 ft.
Blowing Snow: 
None
Wind Direction: 
Southwest
Wind Speed: 
Moderate
Sky Cover: 
Few - Mostly Clear - up to 2/8 covered
Air temperature: 
Above Freezing
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