The tropics pay a visit to the eastern Sierra this weekend. After a week of below normal temperatures and 12-16” of snow a week ago, a warm storm with high snow levels could dump a couple of feet of snow above 8,000 ft. Sustained wind speeds of 60 mph gusting to 100 mph are in store for the Sierra Crest. Unfortunately snow lines will be high after an initial shot of cold air brings 4-8” of snow today. Snowlines then rise to 8,000 ft. - right between the Town of Mammoth and Tamarack Lodge. Some locations are going to get a lot of water out of this storm. The weight of this snow is going to stress the snowpack and make for a wild ride in terms of backcountry avalanche hazard.
The persistent avalanche problem is the current problem this morning. December and January’s weather patterns created highly variable snow conditions and last week’s storm buried 2 to 10 inches of large weak facets and depth hoar under 12-16” of new snow. Some people skied and disregarded the multiple faceted layers, others carefully evaluated slopes because buried weak faceted snow has a nasty habit of producing avalanches on some slopes and not on others.
This layer deserves our attention as the storm comes in with cold temperatures then changing over to warm wet dense snow that will be measured in feet this time. If the storm comes in as forecasted, expect these layers to react to heavy loading Saturday and Sunday. While there was not enough of a new snow load to cause a natural avalanche cycle last week, this storm will load the snowpack in a meaningful way.