Central Sierra Nevada

Widespread icy snow surfaces and strong winds will add additional travel hazards all day today. Long sliding falls are possible. Minimize group exposure to avalanche hazards using normal caution tactics and step back into safer terrain when conditions warrant. LOW avalanche danger exists for all elevations. 

Normal caution

Maximum daytime air temperatures today will only reach a few degrees above freezing in most locations. This is substantially colder than the last few days. These colder air temperatures combined with convective cooling of the snow surface by strong NE winds will keep many slopes frozen all day today. Areas of snow surface melt will be isolated today, limited to slopes with both wind protection and direct sun exposure.

Above about 7,500' to 8,000' where air temperatures were below freezing last night a decent snow surface refreeze is expected. Below 7,500' is more likely to have a weaker surface refreeze as cloud cover last night limited the refreeze potential from radiational cooling of the snowpack.

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 icy snow surface conditions and strong winds making ridgetop travel difficult. 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 occurred over the past few days on E-SE-S-SW-W aspects. For the most part, poor snow coverage exists on these aspects.

* Widespread rain crust covers the snow surface on NW-N-NE aspects that did not undergo melt-freeze over the last few days.

* In the northern 2/3rds of the forecast area, snowpit tests indicate that the Dec 11 persistent weak layer has gone dormant. Some unstable snowpit test results continue to occur (as recently as yesterday) 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.