Central Sierra Nevada
Peligro de aludes
Lo esencial
If accumulating snowfall occurs earlier than forecast, be on the lookout for changing conditions that could increase the avalanche danger beyond today's forecast LOW avalanche danger. This would occur in above treeline and near treeline terrain as drifting snow deposits as new wind slabs. Avalanche danger will further increase tonight and tomorrow as additional snowfall and wind create larger, more widespread wind slabs in above treeline and near treeline terrain.
Avalanche Discussion
Increased cloud cover, increased SW winds, and cooler air temperatures are expected to keep the snow surface frozen today on E-SE-S-SW-W aspects that underwent substantial melt yesterday. This will keep a wet loose avalanche problem from forming today.
Until at least a couple of inches of new snow accumulates, new wind slabs are not expected to form despite the increased SW winds as the vast majority of windward slopes have little to no snow available for transport. Following the onset of new snowfall, expect to see blowing and drifting snow start to deposit as new wind slabs on NW-N-NE-E-SE aspects. If the current weather forecast is correct, this will not occur until tonight. If accumulating snowfall begins earlier than forecast, there could be some small wind slabs that form in lee areas above treeline and near treeline today.
Recent Observations:
* Diurnal melt-freeze conditions occurred over the past 24 to 48 hours at all elevations on E-SE-S-SW-W aspects. Snow surface melt also occurred on some NW-N-NE aspects yesterday with the higher March sun angle. Expect to encounter widespread supportable to breakable surface crust today on slopes that were exposed to the sun yesterday.
* Expect to find lingering recent storm snow, unaffected by melt on well shaded and wind protected N aspects today.
* Snowpit observations have noted that faceting has started to weaken the snowpack around the buried Feb 19 rain crust in the upper portion of the snowpack on some NW-N-NE aspects. New loading of this developing weak layer remains minimal at this time.