The past few warm days wreaked havoc on the snow in the Mammoth Lakes Basin. Saturday's mild temperatures, high relative humidity and mid level clouds added a huge shot of energy into the snowpack on all aspects and elevations- even on slopes above treeline. The only settled moist powder snow without a crust was found in the Coldwater Creek drainage. Despite today's forecasted mild temperatures in the upper 40's, expect crusts to remain frozen on north aspects after the snow loses energy during the night.
Snow depths are similar to last year with around 23-25 inches of snow on the ground. This year is warmer and the recent run of warm days and mild nights have reduced any temperature gradients that might exist in a early winter snowpack to about 1 to 2 degrees C from the ground to the snow surface, a distance of 24 inches or 60 cm.
Extended column tests done on a north aspect at 9,400 ft and on northeast aspects above treeline at 10,000 and 10,200 ft. did not propagate. Snow depths were around 24 inches (60 cm). Facets at the base of the snowpack at the 10,000 and 10,200 ft snowpits were rounding. Wind slabs observed last Thursday ( December 18) that had been sensitive to ski cuts, are well bonded to the underlying snow. There is now a 1 inch hard crust on the surface.
With the onset of cold temperatures that could last for a week, it's easy to picture the shallow snowpack that is now close to 0 degrees C, change character with large changes in temperature between the warm ground and cold snow surface. The generally well bonded snowpack will likely change to a weak shallow pack by New Years.