Evidence of a Persistent Weak Layer on Elephant's Hump

Location Name: 
Elephant's Hump
Region: 
Carson Pass Area
Date and time of observation: 
Mon, 01/29/2018 - 13:45
Location Map: 
United States
38° 41' 30.768" N, 119° 58' 10.956" W
See map: Google Maps
US


Red Flags: 
Rapid warming
Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

We toured around the Elephant's Hump area looking for signs of the loose weak layer of snow buried near a crust at the base of the recent snow (near crust facets). This layer was widespread below the crust buried between 15 and 30cm (6 to 14 in) below the surface on N-NE aspects in near and below treeline terrain. We performed 7 extended column tests at various locations during the tour and 5 out of the 7 produced ECTP results indicating that fracture propagation along this weak layer remains likely. The 2 tests that did not produce unstable results were on an ENE aspect. We did not observe any other signs of instability concerning this layer. Those results and the uncertainty surrounding this persistent weak layer led us to avoid northerly aspects steeper than 30 degrees on our tour. 

In addition to the persistent weak layer, the surface snow had also become wet and sticky on all aspects by 1 pm. Ski cuts on N-NE-E aspects triggered widespread pinwheels and roller balls.

Video: ECTP on the near crust facets on a N aspect at the coordinates attached to this ob.

Photo: Skier triggered pinwheels and roller balls on a NE aspect at 8400 ft. at 1pm.

Snowpack photos: 
Snowpit videos (tests, etc): 

ECTP 18 on a Near Crust Facet Layer near Carson Pass

Weather Observations
Blowing Snow: 
No
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Calm
Air temperature trend: 
Warming
More detailed information about the weather: 

Full cloud cover for most of the day.