Togwotee Pass

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

  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 continually at Togwotee Pass are:

  1. Weak layers are buried ~2+' deep. These layers have produced large avalanches, sometimes triggered from large distances away, in this 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 also exists near the ground across the middle elevations here. 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.

  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.