Salt River and Wyoming Ranges

Avalanche problems

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Very Likely

  Size

  2–3

  Here's all you need to know today:

  • 12-20" of heavy new snow fell last night with very strong winds.
  • Poor snow structure exists on most slopes, with a stiff layer of wind-drifted and heavy snow now overloading a widespread layer of very weak, sugary, faceted snow from the December dry spell.
  • Avalanche danger today will remain basically the same today even if the snow and wind stop.
  • Avalanches could break 3-5' deep in some areas where wind has drifted snow.
  • In the drier portions of the range and lower elevations, slab avalanches will be smaller, 1-3' thick , but still potentially deadly.
  • Groomed trails that cross avalanche paths could be hit.
• 

  Deep Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  2–3.5

  Weak snow formed during a dry period in November persists at the base of the snowpack. This layer is now buried about 4 to 6 feet deep in the Salt River, Snake River, and western portions of the Wyoming Range. It is most widespread and weakest on the north half of the compass. The recent loading events have pushed this deep weak layer to its breaking point in some locations. Deep slab avalanches were observed in the Snake River Canyon three days ago. These avalanches are most likely to occur when an avalanche triggered in the most recent snow steps down to weak old snow and will be unsurvivable.

  Areas in the eastern Wyoming Range, Hoback Canyon, and Gros Ventre Mountains lacked significant snowfall prior to the storm cycle beginning January 4th. In these locations, the new snow has fallen on a snowpack that was primarily made up of weak, sugary snow. Deep slab events are not likely in these locations due to the shallower snowpack.