Snake River Range

Problèmes avalancheux

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Likely

  Taille

  1–1.5

  Wind slabs up to 1 foot thick have formed in the upper elevations after a storm system brought 2 to 4 inches of new snow and moderate winds from the north. Expect to find these generally small slabs on all aspects as winds have shifted from the north to the east overnight. Before the most recent storm, snow surfaces weakened over the last two weeks. New wind slab formations on this surface will be sensitive and human triggers are likely.  Recently, multiple small wind slabs have failed on this weak snow demonstrating the poor structure beneath the new snow. Expect to find these slabs along ridgelines, in cross-loaded gullies, and on steep convex rollovers. Pay attention to signs of wind-loading including the formations of pillows, textured surfaces, or shooting cracks. Triggering a small wind slab can have large consequences, especially near gullies, cliff bands, and trees. Moving to terrain sheltered from the wind will help you avoid this problem.

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Unlikely

  Taille

  1.5–2.5

  Triggering a large hard slab avalanche is unlikely. Weak layers of snow buried 2-4 feet deep in the Snake River range are adjusting to the weight of the snowpack.  Instability is most likely to be found in very steep, north-facing terrain. Triggering a large avalanche will be most likely in thin rocky areas where you can impact the weak layers.  Larger triggers, such as groups, snowmobiles, or falling cornices, will increase the odds of impacting these weak layers.