Red Cone - Wind Slabs

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SNOWPACK OBSERVATION
Red Cone
Submission Info
Forecaster
Tuesday, February 27, 2018 - 2:45pm
Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Obvious avalanche path
Red Cone 37° 35' 49.3368" N, 119° 1' 28.5276" W
Snowpit Observations
More detailed information about the snowpack: 

Toured up to Red Cone to assess the new snow bonding and Wind Slab development. In the lower elevations the recent series of “Slider” type storms (cold northerly storms, low density snow) have helped with the snowpack retention and depth, especially from ~8500’ to 9000’ where the snowpack was getting very thin and becoming quite patchy. You can at least now not have to walk between patches. However, it is still quite thin, many potential hazards just below the surface. Noted Surface Hoar (5 to 10mm) development from 8500’ all the way to 10000’ where light Easterly breezes were beginning to redistribute them, leaving patches undisturbed. Some riming above ~9800’ noted frosting the trees. Hand shears varied with snow density. From ~8500’ to ~9800’ in the protected trees, the snow was loose, with a slight hint of a slab forming in the top 5cm. As you approached the Red Cone east rim (10000’) and break out of the trees, noted some stiffing of the surface snow and obvious drifting from multiple directions and the top 10 to 20 cm exhibiting more slab like characteristics with easy to easy moderate shears. Winds - signs of North and Northeasterly winds during the night, moderate Easterly during the day above ~10000 producing light drifting. Recent drifting along the east rim was substantial but ski cuts and cornice drops produced no results. The drifting along the east rim was quite impressive while the north entry into the bowl remained scoured and had a few elevated ski tracks. Further test slopes yielded no results other than Loose Dry sloughs on steeper slopes. On approach, noted 1 D1.5 on the slopes above Lake George (originating ~9300’), several what appeared to be Loose Dry sloughs on steep unsupported terrain, and a likely D2 on the southern slopes of Mammoth Mountain outside the boundary. All activity appeared to have taken place during the night. No other activity noted along the Crest but clear signs of some large drifts scatted throughout the treeline and above. Temperatures remained below freezing throughout with no signs of warming on southerly aspects or dripping from the trees. 

 

Snowpack photos: 
Red Cone, West Aspect, Small Cornice
Red Cone, Approach Trees, Surface Hoar
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Precipitation: 
None
Air temperature trend: 
Cooling
Wind Direction: 
East
Accumulation rate: 
More detailed information about the weather: 

Easterly winds were blowing on the low end of moderate with light saltation filling previous skin track above ~10000'. Temps remained cold throughout the day.

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