Central Sierra Nevada

During the daylight hours today, triggering an avalanche remains unlikely. Normal caution is advised. Avalanche danger will increase tonight and tomorrow as a warm, powerful storm impacts the region. 

Normal caution

Another round of minor wet snow surface snow conditions without significant instability is expected today. Increasing winds ahead of an approaching storm will provide some convective cooling of the snow surface in wind exposed areas. This will mitigate some of the snow surface warming as compared to the past three days. Use the best practices associated with normal caution for travel in avalanche terrain that minimize the consequences of encountering any isolated areas of unstable snow.

Loose wet and wind slab avalanche problems are expected to develop late tonight into tomorrow morning following the onset of rain and snow.

Recent Observations:

• Surface hoar that is commonly buried less than an inch below the snow surface across NW-N-NE aspects will likely be destroyed by substantial rain in the areas where it has survived the warm air temperatures of the past few days. Only isolated areas above 9,000' to 10,000' might continue to hold problematic surface hoar going into the next storm cycle.
• In isolated locations along the eastern side of the forecast area, the old Dec 1 facet layer near the bottom of the snowpack on northerly aspects remains in poor condition to handle the forecast loading of 2 to 4 inches of SWE that is expected tonight into Wednesday. Throughout the vast majority of the forecast area, the old Dec 1 layer has gained sufficient strength to handle substantial loading.
• Variable snow surface conditions exist across the region, especially at low to mid elevations.