Solar Heating and Near Surface Facets in the BWRA

Location Name: 
Koenig Lake Area
Region: 
BWRA
Date and time of observation: 
Thu, 03/04/2021 - 13:00
Location Map: 


Red Flags: 
Rapid warming

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

Today we snowmobiled up to the Koenig Lake area. Skies were sunny, temperatures were warm, and the wind was calm at lower elevations and light out of the south at ridge tops. 

Snow surfaces on southely aspects experienced significant solar heating today after a solid freeze last night.  Even with the heating, loose wet avalanches remained hard to trigger. The snow on southerly aspects near and above tree line generally remained supportable except for in some areas near rocks and cliffs. Descending a S aspect between 10,500 ft and 9500 ft around 2pm, skiing conditions were good and generally just corn. Near ridge tops the light S wind was only allowing a small amount of surface melt. Lower down, near rocks and cliffs, the snow surface was more like mashed potatoes, but generally still supportable. Ski cuts on some steeper rocky rolls produced no results, but in the right steep, rocky spot today it likely would have been possible to trigger a small loose wet avalanche. Many freeze thaw cycles, and rough snow surfaces seem to be preventing significant loose wet avalanches. 

Digging a pit on a loaded SW aspect at 9400 feet we observed a relatively isothermal temperature gradient, but the snowpack was still transitioning to an isothermal state.  We observed wet melt forms and ice crusts near the surface, moist rounds in the mid-pack, and moist rounding facets near the ground. No layers of concern. Percolation columns were observed in the upper portion of the pack, and in areas it appeared that water was pooling above crusts. 

Wind exposed northerly aspects continue to harbor widepread hard and slick wind board and some sastrugi. On wind protected northely slopes, we observed near surface facets at the snow surface and improved riding conditions. 

We observed an old natural loose wet avalanche on a steep, rocky ENE aspect at 10,000 ft, likely from 2/22. We also observed an old wind slab on a NE aspect at 9,800 ft, unknown trigger or date, but the crown looked settled and old. 

Unfortunately the 108 has quite a few sections of bare pavement at the moment. Hopefully next week's storms pan out and cover them up...

Snowpack photos: 
Weather Observations
Blowing Snow: 
No
Cloud Cover: 
Clear
Air temperature: 
Above Freezing
Wind Speed: 
Light
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
South
Accumulation rate: 
None