Central Sierra Nevada
Peligro de aludes
Lo esencial
Variable snow conditions including icy crusts and thick wet snow pose a greater hazard than avalanche concerns today. Travel using normal caution tactics and be willing to step back into safer terrain if signs of instability are encountered, especially where the snowpack is shallower and weaker. LOW avalanche danger exists for all elevations.
Avalanche Discussion
Another decent overnight snow surface refreeze is expected to have occurred last night from radiational cooling of the snowpack under clear skies. This will have occurred despite above freezing air temperatures overnight at the mid and upper elevations. Areas of snow surface melt will occur again today in areas of direct sun exposure. On slopes exposed to today's NE winds, snow surface melt will be much more limited due to convective cooling. Problematic amounts of loose wet snow instability are not expected due to the weak incoming solar radiation, low sun angle, and the overall short length of daylight hours this time of year.
Slab avalanche activity remains unlikely today. No avalanches have been reported on the Dec 11 persistent weak layer in 3 weeks. Observations indicate that this weak layer has become dormant in most places. If a slab avalanche were to occur anywhere today it would most likely happen on the eastern side of Carson Pass or Ebbetts Pass where the relatively shallower snowpack has remained weaker.
Create travel plans focusing on terrain and snow conditions that match your group's skill level, taking into account additional hazards created by snow surface conditions. Step back into safer terrain when conditions warrant. Even though the avalanche danger is LOW, stay alert, and don't ignore any signs of instability no matter how isolated.
Recent Observations:
* Diurnal melt-freeze conditions are occurring on E-SE-S-SW-W aspects. Generally poor coverage exists on these aspects. Areas of supportable snow cover exist on open slopes away from exposed rocks and vegetation.
* The majority of recent observations show improving stability associated with the Dec 11 persistent weak layer. In the northern 2/3rds of the forecast area, snowpit tests indicate that this layer has gone dormant. Some unstable snowpit test results continue to occur 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 overall shallower and weaker.