Central Sierra Nevada

Problemi valanghivi

• 

  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

  Increased winds, slightly cooler temperatures, and some afternoon clouds may help slow down today's warming. Still, the strong April sun and temperatures well above freezing should melt through last night's refreeze and leave a layer of unstable wet snow on most aspects and elevations. If rain falls on the snow this afternoon, more wet snow will exist. This wet snow could slide down steep slopes, resulting in wet loose avalanches. Some of these may remain small but could still push people into terrain traps, such as cliffs, rocks, gullies, or trees. Long, steep slopes can produce larger wet snow avalanches since these avalanches gather more snow as they move downhill.

  Roller balls, pinwheels, and sinking into boot-top deep wet snow represent clues that wet loose avalanches can occur. Once the snow surface stops feeling frozen and starts feeling wet and mushy, it's time to switch to lower-angle slopes without steep slopes above them.

  

• 

  Cornices

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Possible

  Dimensione

  1–2

  Even though the NE winds eroded some cornices, many ridgelines around the forecast area still have large overhanging cornices. These will continue weakening in today's warm weather, and some could collapse. Significant uncertainty exists about exactly when specific cornices will fail. If a person does trigger a cornice failure, they could take a long fall and/or get crushed by large cornice pieces. Cornice collapses may also entrain snow on the slopes below them or even an unlikely wind slab on a steep slope.

  Cornice collapses almost always surprise people. They fail farther back from the edge than expected and break wider than expected. If your route takes you along a corniced ridge, keep exposed rocks or trees between you and the cornice edge. Also, be wary of traveling on slopes under cornices. It's best to avoid these slopes, but if you have to travel on them, spend as little time as possible doing so.