Wet and Dry Facets on Rubicon Peak

Location Name: 
Rubicon Peak
West Shore Area
Date and time of observation: 
Mon, 01/08/2018 - 10:30
Location Map: 
United States
38° 59' 29.4144" N, 120° 8' 5.3196" W

Red Flags: 
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain

Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

Wet snow existed on the surface and rain on snow was occurring up to 8700 ft. on Rubicon Peak today. Little to no new snow had accumulated by 1pm. The recent snow that fell on Friday night sat on top of a rain crust on top of a loose weak layer of snow (the facets that formed during the long dry period). This facet layer was wet and starting to clump together at elevations below 8500 ft. and was moist to dry at elevations above 8500 ft. Tests targeting this layer indicated that it remains weak regardless of whether it is wet or dry (ECTP @ 8600, PST 45/100 end @8900 ft). In areas where a wind slab existed between the facet layer and the more recent snow, the facet layer was drier and less cohesive. Between 8200 ft. and the summit of Rubicon some minor cracking occurred around my skis. The largest of the cracks extended about 1 to 2 ft. away from my skis.

Above 8800 ft. wet sticky snow existed on the snow surface and ski cuts on steep slopes caused small roller balls and pinwheels. Below 8800 ft, the snow surface had 1 to 2 inches of loose wet snow that resembled corn snow above a semi-frozen rain crust above the old facet layer. 

Photo: ECTP8 on a N aspect at 8600 ft. A moist to wet facet layer below Friday night's snow was the failure layer.

Snowpack photos: 
Weather Observations
Blowing Snow: 
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Rain up to 8700 ft. Light snow above 8800 ft. and a mix of rain and snow in between. 

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