With multiple feet of new snow falling on the Sierra over the past two days, the Sierra Avalanche Center has reported “very dangerous avalanche conditions” from Yuba Pass and Ebbetts Pass, including the Lake Tahoe area.
The mountain snowpack from October and November has weakened, meaning the massive snowfall predicted to fall through Tuesday will sit on an unstable foundation. This will likely cause natural and human-triggered avalanches, some of which could be large and destructive. Avalanche officials are urging the public to stay away from avalanche terrain, including steep slopes below treeline.
“Conditions have changed from last week,” wrote the Sierra Avalanche Center in their report. “The heavy load of the storm snow today could overload many of these weak layers and cause large and destructive avalanches that propagate wide and travel long distances. Persistent slab avalanches can be remotely triggered, have wide propagation, and could wrap around terrain features. This persistent slab problem exists in most areas that have enough snow coverage for recreating on. Any avalanches associated with these weak layers could have severe consequences. Travel in avalanche terrain is NOT recommended today.”
Multiple feet of snow have already fallen on the Sierra above 8,500 feet, with the storm expected to peak on Monday. At the highest elevations, more than 100 inches could fall. While this may seem like a perfect time for a backcountry adventure, there are considerable risks immediately after this storm.
If you choose to adventure out into snowy wilderness this week, use extreme caution and bring the proper avalanche equipment. Stay safe out there!