Backcountry Avalanche Forecast Central Sierra Nevada

While some of the slabs of wind-drifted snow that have formed over the last few days may have gained strength, others could remain unstable today, especially in areas where these wind slabs exist on top of weak, sugary snow (facets). In these places, a person could trigger a wind slab lower on the slope, and wider-than-expected avalanches could still occur. In many places, the wind slabs also rest on top of old crusts, which can provide an efficient sliding surface.

Look for signs of wind-blown snow, like cornice formations, wind pillows, or other signs of snow distribution on the ground to identify areas with wind slabs. Exercise increased caution around places where wind-drifted snow has been deposited.

Weak snow existed in many areas before this storm, and now, a thin layer of heavy, cohesive new snow rests on top of these old, weak layers in some places. In some areas, the weak layers seem to support the new snow, but other areas exhibit signs of instability like snow surface cracking. Despite some observations indicating that these layers may be gaining strength and no reported persistent slab avalanches, it may still be possible to trigger a persistent slab avalanche, especially on NW-N-NE aspects at upper elevations. In more isolated areas, weak faceted snow also exists on E and W aspects. There is a high amount of uncertainty here with highly variable weak layer distribution and strength. This uncertainty makes predicting exactly where or if persistent slab avalanches may occur difficult at best.

Any snowpack collapses, whumpfing sounds, or shooting cracks represent signs of unstable snow. If you encounter any of these signs of instability, avoid NW-N-NE aspect avalanche terrain in the area.