Central Sierra Nevada

Problemi valanghivi

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Possible

  Dimensione

  1–2

  The winds shifted to the NE overnight and have remained strong enough to transport snow. These NE winds blew snow back across the ridges to deposit new slabs of wind-blown snow onto the N-NW-W-SW-S-SE aspects. They will continue to scour snow away from slopes that the SW winds loaded yesterday and move it across the ridges today. Wind slabs will most likely exist near ridgelines or on cross-loaded terrain features like gullies. These wind slabs may not have bonded to the snow below them, and human-triggered wind slab avalanches will be possible. Today's strong sunshine could also help to weaken some of the wind slabs, especially those on the SE-S-SW-W aspects. 

  Clues like blowing snow, ripples in the snow surface, and drifts of snow can help identify where wind slabs have formed. Snow surface cracking provides a good sign that the wind slabs remain unstable. Watch out for any avalanche terrain on the downwind side of ridgelines that appears filled in and smoothed out compared to the surrounding terrain. Identify these areas and move around them with increased caution today.

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Possible

  Dimensione

  1–2

  The strong, late-March sunshine should provide enough warming for wet snow to form on sunny slopes today. Wet loose avalanches that involve yesterday's new snow will be possible today. Areas around rocks and trees or in gullies may warm up first followed by open sunny slopes sheltered from the wind. Wet loose avalanches gather more snow as they move downhill, so long steep slopes can produce larger wet loose avalanches. Terrain traps like gullies, cliffs, and creeks can magnify the consequences of these avalanches. Strong NE winds and cooler temperatures at the upper elevations should help limit warming on some upper elevation slopes. 

  Rollerballs, pinwheels, or other signs of wet snow all indicate that the wet snow could be unstable. Traveling on lower-angle terrain that is not below avalanche terrain or moving to an area where the snow remains cold represent good strategies to avoid wet snow problems.