Central Sierra Nevada

Avalanche activity remains unlikely today, but things will begin to change as new snow and wind start to form small snowdrifts near ridgelines this afternoon and evening. By tomorrow these may grow into wind slabs if enough snow accumulates. Widespread firm icy conditions present additional hazards today including long sliding falls. LOW avalanche danger exists for all elevations. Travel using normal caution and be willing to step back into safer terrain if conditions warrant.

Normal caution

Expect firm icy surfaces on all aspects at all elevations today since cloud cover and cool temperatures should prevent the refrozen crusts from softening. As new snow starts to fall this afternoon, it will begin to cover the crusts with a thin layer of soft snow creating "dust on crust" conditions. The new snow and wind will also start forming snowdrifts near ridgelines on the leeward NW-N-NE-E-SE aspects this afternoon and evening. Since the forecast only calls for 1 to 3 inches of new snow by this evening, wind slab formation should remain minimal today unless more snow falls than forecast. More problematic wind slabs may exist on wind-loaded slopes tomorrow, especially if storm totals reach the higher end of forecasted amounts. 

While significant avalanche activity remains unlikely today, other hazards still exist including uncontrollable, long, sliding falls on icy slopes. Conditions will also begin changing quickly as new snow and wind impact the forecast area. Monitor the snowpack and conditions while traveling. Be willing to step back into safer terrain as things change or if conditions start to exceed your group's comfort level. Even though the avalanche danger is LOW, stay alert, and don't ignore signs of instability or unforeseen changes in weather or snow conditions.

Recent Observations:

* Yesterday observers reported firm icy conditions on most aspects on Red Lake Peak (Carson Pass) and Castle Peak (Donner Summit). Observers also reported some weak snow just below the surface crust in some more shaded places in both these areas. The rain crust remains widespread across all slopes and elevations in the forecast area. 

* Enough warming occurred in for a limited amount of soft wet snow to form on southerly aspects that received direct sun on Red Lake Peak and Castle Peak yesterday. 

* Snow coverage on the sunny SE-S-SW aspects remains limited and exposed ground exists on many of these aspects. 

* In the northern 2/3rds of the forecast area, snowpit tests indicate that the Dec 11 persistent weak layer has gone dormant. Snowpit tests in some places continue to produce unstable results in the southern 1/3rd of the forecast area, especially on the eastern side of the Carson Pass and Ebbetts Pass areas where the snowpack remains shallower and weaker. Snowpit data across the forecast area (including the Carson and Ebbetts Pass areas) has shown mostly strong supportable snow above the Dec 11 facets.