Salt River and Wyoming Ranges

Problemas de aludes

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta montaña
  • Límite del bosque
  • Bajo el límite del bosque

  Probabilidad

  Possible

  Tamaño

  1–2

  Much of the recent wind slab activity has been observed on the aprons below cliff bands and around rocky, alpine features that drive the wind. Today, expected to encounter slabs in similar areas that may grow in size and distribution today. Drifted areas may still feel like powder, but may have just enough added cohesion that you could trigger a slab avalanche. In addition, yesterday's snowfall was warmed by prolonged clearing and generally has had time to settle into denser, more cohesive snow. Slabs may be sitting atop weak old snow surfaces making them more reactive to your weight. Recognize that wind-loading also adds stress to other recent interfaces buried in the top 50 cm of the snowpack. 

  ADDITIONAL DISCUSSION

  The onset of snowfall on Monday buried a variable snow surface, in addition to another mid-storm interface from clearing, variable skies yesterday. Temperatures are also expected to warm throughout snowfall today. I observed several avalanches that failed on Monday's interface, and I expect more may fail today with additional snowfall. It will take some time to see how new snow is bonding to old snow and thin crusts formed yesterday and take the time to observe how this interface will behave.

  The takeaway should be that new snowfall will move easily today in steep terrain regardless of exposure to the wind. This will hold particularly true if snowfall amounts end up on the higher end (8-10  inches). If not, expect this to be less of a problem, and expand your options accordingly. Regardless of amounts today, however, loose snow (sluffs) in steep, exposed terrain will continue to pose an additional hazard. Yesterday in the Snake River Range, I observed over 10 loose snow avalanches in consequential terrain and funneled features that certainly bordered on being large avalanches for "just" loose snow. Bear this in mind when choosing terrain today. 

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta montaña
  • Límite del bosque
  • Bajo el límite del bosque

  Probabilidad

  Possible

  Tamaño

  1.5–2.5

  A loading event has brought improved skiing and riding conditions to our area, but our focus is still on how persistent weak layers will react to additional snowfall. Good things to keep in mind, particularly in the Wyoming Range, are:

  1. Weak layers that formed during the month of February are now buried ~2' deep. These layers have produced avalanches across most of our forecast area. The pattern of activity outlined by these avalanches points to these layers being most unstable on slopes that face the sun, where they are accompanied by crusts, but they have also produced slides on shaded aspects. 
  2. A pile of large-grained, weak snow exists near the ground in parts of the Wyoming Range. You are more likely to trigger slides on the weak layers higher up in the snowpack, but any slide triggered on this deeply buried weak snow is likely to be unsurvivable.

  The possibility of triggering a slide here will be on the table for some time to come. If you choose to enter avalanche terrain, be alert that at least one of these weak layers almost certainly exists in the snowpack underneath you. Even as the danger decreases we continue to advise cautious and conservative terrain selection. Be alert to the consequence of being caught in a large avalanche in the terrain you are recreating in.