Salt River and Wyoming Ranges

Problemi valanghivi

• 

  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

  Continued wind transport was observed yesterday in the alpine terrain of the Greys River. This avalanche problem (and the hazard range of this problem) will be very variable across this zone, with snow amounts favoring portions of the Snake, Salt, and northern portion of the Wyoming range, with far less snowfall noted in the southern portion of the Wyoming. Areas seeing less snowfall will trend towards lower hazard.

  These wind slabs are becoming less sensitive to a rider's weight, but some are sitting atop weak snow surfaces and remain touchy.  Recognize that wind-loading stresses the weak layers buried in the snowpack (described in Problem 2 below). Any wind slab you trigger could step down to deeper layers, producing a much larger, more dangerous avalanche. While the slabs you encounter today are less likely to be large, they may produce slides large enough to knock you off your feet or sled and send you downslope. Look for evidence of wind drifting, such as dune-like drifts and ripples on the snow surface. Cracks shooting out from your skis or board are a sure sign that you've found a sensitive wind drift. 

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Possible

  Dimensione

  2–3

  As we move away from any loading event, we get two things: improved riding conditions and a refocusing of our attention on the persistent weak layers buried in the snowpack. Each time it has snowed in this range, large avalanches on this weak snow have been noted, however there are very variable in where they occur throughout the range. The primary culprit remains weak snow buried in January, now 3-5' below a firm, cohesive slab. Areas that have held shallower snow all season hold higher odds of encountering this problem now, however active weather throughout the week means we need to continue looking for this layer and assessing its activity of it on our slope of choice. This combination is primarily found on the northern half of the compass. Lower elevations contain this same combination, as well as just generally weak snow on sheltered aspects. 

  The extreme spatial variability of the snowpack in the Greys makes this problem difficult to manage. The best way to assess weak snow on any slope is to probe depths or trench your track to dig down. Shallower slopes (those with less than 3-4 feet of snow) remain suspect. It is worth carefully reading or submitting any recent observations over the past week in areas you frequent and grasp any trend with activity.