Tracking Solar Warming on Red Cone

Submission Info
Monday, February 5, 2018 - 11:00am
Red Flags: 
37° 35' 41.28" N, 119° 1' 36.84" W
Snowpit Observations
More detailed information about the snowpack: 

Toured up the usual approach to the top of Red Cone to track solar heating by aspect and elevation. Skied E and SE aspects back down the Tamarack ski trails at Lake George and out.

Most apsects below ~9200' had at least a thin (1cm) melt-freeze crust on the surface this morning. Coverage below that elevation is rapidly becoming patchy (see photo of a N aspect above Lake George). Between ~9200' and ~10,000' melt-freeze surfaces versus cold winter surface facets depended on mirco-scale sun exposure and re-radiation potential such as tree coverage or proximity to rocky areas. For example, at 2 shady locations just 20' apart on a NNE aspect at 9400' at 1000am, 1 area with tree coverage had a melt-freeze crust and Tsurf = -5 deg C while another area that was open and away from the trees had wintry surface facets and a Tsurf = -8 deg C. Above ~10,000' aspect was a much more reliable indicator of spring versus winter snow conditions. E-S-SW aspects were melt-freeze while W-N-NE aspects had cold near surface facets and previously wind affected winter snow.

Clear skys overnight allowed things to stay cold and icy later into the morning, but by 940am E aspects at 9100' were beginning to soften and peak corn skiing was almost past (sinking in to almost boot top) as I descended the E aspect of Red Cone at 10,400' at 1100am. Increasing thin clouds throughout the day also helped to warm more northerly aspects at lower elevations by noon. Of note, snow depth on solar aspects is waning and barely hidden obstacles are becoming a problem (a few new scratches on my skis).

2 sets of field weather observations taken to get specifics about heating on solar aspects. Site 1 was a large opening in the trees on a SW aspect at 9800' taken at 1020am: Sky = Few clouds, Wind = Calm, Surface snow = dry, frozen, melt-freeze crust, Ski pen = 2cm, Boot pen = 40cm, Snow depth = 108cm, Tair = 6.5 deg C, Tsurf = 0 deg C, T-20 = -1 deg C. Site 2 on the N-S summit ridge of Red Cone on a SSW aspect taken at 1100am: Sky = Scattered clouds, Wind = Light from the NW, Surface snow = dry, frozen, melt-freeze crust, Ski pen = 2cm, Boot pen = 20cm, Snow depth = 55cm, Tair = 7.5 deg C, Tsurf = 0 deg C, T-20 = -2 deg C.

No signs of any avalanche activity by the time I got back to the Tamarack ski trails around 1130am. There were a few small rollerballs from my turns, especially in a steep, rocky, E facing chute above Crystal Lake at 1100am.

Snowpack photos: 
Patchy coverage above Lk. George
Weather Observations
Blowing Snow: 
Air temperature: 
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: 
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