Back Side of Mammoth Mtn. to Horseshoe Lake, Early Warming

SNOWPACK OBSERVATION
Submission Info
Forecaster
Saturday, February 3, 2018 - 10:00am
Red Flags: 
37° 37' 23.16" N, 119° 2' 0.6" W
Snowpit Observations
More detailed information about the snowpack: 

Traversed off the back of Mammoth Mtn. towards Horseshoe Lake to see how early southerly aspects were warming. Skied down the upper part of Reds Creek drainage to about 10,200' where I traversed around across SW-S-SE-E aspects, and skied down to Horseshoe and out the Tamarack ski trails.

Warm day again today despite moderate NE winds blowing across the top of Mammoth where the snow was still hard and icy, even on SW aspects. I stopped as soon as the snow began to show signs of thaw: on a SSW aspect at 10,240' at 10am. The top 1cm of the snowpack was moistening here. Tair = already 7 deg C, Tsurf = already 0 deg C, Sky =  scattered clouds, Wind = light from the East. Things only got wetter from here, and quickly. Coverage, even at upper elevations, on sunny aspects was poor (see photo taken looking up slope on a S aspect at 10,000'). Snow depth ranged from 0-30cm on steeper sunny slopes above ~9600', and was about 65cm on slopes with less direct sun effect above Horseshoe Lake. All southerly snow surfaces were spring-like melt freeze, but no signs of natural loose wet avalanches, or even rollerballs anywhere. Most places I poked around below 10,000' the top 15-20cm was moist corn snow on top of a decomposing melt-freeze crust. More moist round snow grains under that top crust, then another harder melt-freeze crust with dry snow underneath. The bottom of the snowpack, on E aspects was moist rounding facets.

General impressions: If you want to ski February corn on south aspects, leave early! Things are getting soft above 10,000' by 1030am, and by then the surface might be too soft at lower elevations.

Snowpack photos: 
Coverage on S aspects
Weather Observations
Blowing Snow: 
Air temperature: 
Wind Speed: 
Precipitation: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
More detailed information about the weather: 

ESAC receives support from ...