Sawtooth & Western Smoky Mtns

Problemi valanghivi

• 

  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

  We received reports of a handful ofhuman-triggered avalanches over the weekend. Many of these were remote triggers, failed on the weak sugary facets buried ~2 ft down and are clear indicators that the January drought layers are still a threat. Triggering similar avalanches today is most likely in recently wind-loaded terrain. Persistent Slabs can release in surprising ways. They can be much wider than expected and be triggered remotely—from flat terrain below, above, and to the sides of steep slopes.

  Last week's storm snow buried weak facets, surface hoar, and crust-facet combinations on many middle and upper-elevation slopes. More deeply buried weak layers that formed during the extended Jan-Feb drought (facets, crust + facets, surface hoar) have not healed and remain suspect, primarily on NW-N-NE-E aspects above and below the middle-to-upper elevation transition.

  Avoiding steep, wind-loaded slopes is the best way to avoid trouble today. Please remember that avalanches are also possible in more sheltered terrain. Snowpack cracking and collapsing are clear signs of unstable conditions.

  

• 

  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

  The winds were blowing hard enough to move and redistribute snow in both open alpine zones as well as in more sheltered locations yesterday. Expect to find a fresh crop of reactive wind slabs in exposed upper and middle elevations today. These are most commonly found near or 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 sensitive slab. Look for wind-affected surfaces, dunes, or drifts.  Feel for stiff slabs overlying weaker or softer snow.

  You can manage your exposure to this problem by identifying and avoiding wind-loaded slopes. Smaller wind slabs can also act as effective triggers for larger persistent slab avalanches described above.