A rapid, critical load has been added to the snowpack. Touchy conditions with high consequences will be widespread on Wednesday. Travel in avalanche terrain is not recommended.
Two layers of surface hoar from late December are now buried 60-120 cm deep. These layers have produced many large avalanches across aspects and elevations with incremental loading from new snow and wind. Significant loading from new snow has the potential to bring these weak layers to their tipping point and to create conditions for step-down avalanches.
40-60 cm of snow is forecast to accumulate in the region forming new, reactive storm slabs. There is potential for storm slabs to step down to deeper weak layers, forming large and destructive avalanches. Storm slabs will be more pronounced in lee terrain features.
Tuesday night: Cloudy, 20-30 cm of snow, moderate southwest wind, alpine temperature -4 C.
Wednesday: Cloudy, snow tapering by noon with 5-10 cm of accumulation, moderate west wind, alpine temperature -9 C.
Thursday: Partly cloudy, isolated flurries with trace accumulations, light west wind, alpine high temperature -10 C.
Friday: Cloudy, 5-15 cm of snow, moderate south wind, alpine high temperature -10 C.
There have been many reports of large (size 2-2.5) avalanches from both natural and human triggers on a variety of aspects and elevations releasing on surface hoar layers formed in late December. These avalanches have been breaking 60-90 cm deep. Several of them have been remote-triggered.
As the new snow settles, storm slab avalanches are likely to be triggered and have the potential to step down to these deeper layers, forming very large and destructive avalanches.
Up to 60 cm of new snow is forecast to accumulate by Wednesday afternoon with moderate to strong southwest wind. This will form a new storm slab problem that will need to be managed conservatively. Expect areas where the snow is being drifted by wind to be more reactive.
Two layers of surface hoar from late December are now buried 60-120 cm deep. These layers continue to produce large avalanches across aspects and elevations. Small avalanches in the new snow have the potential to step-down to these persistent weak layers.
