Sawtooth & Western Smoky Mtns

Problemi valanghivi

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Very Likely

  Dimensione

  2–2.5

  Expect to trigger 2-4 foot thick slabs in wind-loaded terrain. Avalanches could release naturallly, and cornices could fail and trigger slabs on the slopes below.  Avalanches could be wider than you expect, and very easy to trigger, due to persistent weak layers buried below the recent load from this storm. 

  The size and chance of avalanches will increase as the day progresses. Expect to find slabs near or just below ridgelines, along mid-slope ribs, and on aprons beneath chutes. Cracks shooting out in front of your sled or boards mean you've found a wind slab. 

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Likely

  Dimensione

  1.5–2.5

  Many steep slopes that are even subtly wind-affected are at their tipping point; avoid all large or consequential avalanche paths that could have any wind-affected snow. In areas sheltered from the wind, persistent slab and loose snow avalanches are possible. The size and chance of avalanches will increase as the day progresses. 

  The 20-40" of recent snowfall is stressing very weak snow that formed during the month long drought, including surface hoar, facets, and facet + crust combinations. These layers exist on many slopes, the worst of which are found at middle and low elevations. 

  A kiss of wind, warm temperatures, or a brief bit of sun is all it takes to consolidate the storm snow into a touchy slab. Although smaller than the thicker wind slabs described above, this problem is tricky. Slabs may release in surprising ways and break wider than expected. You can trigger avalanches remotely—from above, below, or to the sides of steep slopes. It's hard to predict which sheltered slopes are unstable, so build a wide safety margin to handle the uncertainty. 

  Expect heavy sluffing on many steep slopes. Triggered slides of any form may quickly gain mass as they easily entrain the weak facets below, and large sluffs are likely to trigger wider slab avalanches as they move downhill.