Sawtooth & Western Smoky Mtns

Problemi valanghivi

• 

  Loose Dry

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Certain

  Dimensione

  1–2

  You are near certain to trigger sluffs in very steep terrain, and some of these could be big enough to knock you over or bury you. The chance of natural loose snow avalanches will rise as direct sunlight shines on steep slopes. The increased threat will follow the sun around the compass, beginning on E-SE aspects in the morning, moving to S-facing slopes by noon, and finishing on SW-W aspects in the afternoon. The steep, craggy terrain in the Sawtooths is perfect for producing these avalanches. 

  Many of these slides will be small and relatively harmless; however, large slopes, chutes, and couloirs could produce big, powerful sluffs that could easily catch, injure, or bury people. Be aware of the terrain above you and where an avalanche could carry you. Don't underestimate the potential size of the sluffs. 

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Likely

  Dimensione

  1–2

  You could trigger soft wind slabs up to 3 feet thick in exposed terrain. Yesterday's heavy snowfall and wind formed slabs, drifts, and cornices near upper elevation ridgelines and in some middle elevation terrain. Today's wind may continue building slabs and wind features. In the craggy Sawtooth Mtns, also watch for stiff pillows of snow at the bottom of large cliff faces, chutes, and couloirs.

  Cornices, drifts, dunes, rippled snow surfaces, and chalky snow pillows are visible clues that the wind has been at work. If you see cracks shooting out in front of your skis or boards, you've probably found a wind slab. If you feel the snow stiffen beneath your sled or skis, its time to steer clear of large or consequential avalanche paths.

  Cornices have grown substantially this week, and the most recent growth may be very soft; natural or human-triggered cornice fall can trigger wind slabs beneath cornices. Give large or overhanging cornices a wide berth. 

  In wind-sheltered terrain, today's sunshine may consolidate and stiffen the fluffy powder near the surface. This process raises the possibility of natural or triggered avalanches involving yesterday's snowfall on very steep slopes. Conditions can change rapidly on sun-drenched avalanche paths. 

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Possible

  Dimensione

  2–3

  It would take some bad luck, but triggering a large, destructive 3-6 foot thick avalanche isn't off the table yet. These slides would fail on persistent weak layers (crusts, crusts and facets, or facets) in the middle or bottom of the snowpack. You're most likely to trigger them on middle and upper elevation slopes commonly exposed to the wind.  

  Persistent Slab avalanches can release in surprising ways. You can trigger them from flat or low-angle terrain long distances away from steep slopes, and they can break far above you. They can break hundreds or thousands of feet wide. Before triggering an avalanche, you probably won't experience snowpack collapsing or other obvious signs of instability. 

  You're most likely to trigger one of these beasts in steep, rocky, wind-swept alpine terrain and in the northeastern corner of this zone. Here, thin areas of the snowpack make it easier to trigger avalanches.