Selkirk Mountains

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

  Moderate winds and strong gusts that are forecast to increase in their intensity throughout the day, will be transporting new snow onto the lee side of ridges and other terrain features. This freshly drifted snow will quickly form sensitive slabs over a stout widespread crust that will act as a good bed surface for moving snow. Prevailing winds will be out of southwest and west today, meaning that Wind Slabs will readily form on northwest to north through southeast facing slopes. These sensitive slabs might extend further down from ridge crests and out of the ordinary places as windspeeds and snow accumulations ramp up throughout the day.Some tell-tale signs that you are in an area with fresh Wind Slabs is seeing lens shaped pillows of snow with a styrofoam-like texture, noticably denser snow overlying soft snow, and cracking that extends beyond your skis. If you find some of these features or notice signs of instability, steer toward more wind scoured aspects and low-angle slopes to reduce your chances of triggering a large avalanche.

  

• 

  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

  A 2 to 3-foot-thick cohesive slab overlies two buried surface hoar layers. One got buried at the end of January (1/28) and the other in mid-February around Valentine’s Day (2/14). The slab above has stiffened and settled due to wind, warmer temperatures, and natural settlement. As the slab has strengthened, the likelihood of human-triggered avalanches has decreased, and natural avalanches have become unlikely. Although the snowpack has been trending in the right direction during the last week, the potential consequences remain significant if one of these persistent weak layers is woken up and an avalanche occurs. 

  Snowpack feedback and signs of instability in the form of audible collapses, shooting cracks, or worrisome test results are becoming harder to come by, and there will likely be little to no warning before you trigger a large avalanche. Shaded, more wind-protected slopes that favor the northern half of the compass are the most likely places where looming persistent weak layers will be intact. Areas with a thinner or softer overlying slab may act as trigger points and the inital fracture could expand to places where the slab is deeper and more destructive. Navigate around slab margins, rocky slopes, and steep convex rolls where snow depths are likely shallower if traveling through avalanche terrain.

  

• 

  Loose Dry

  N

  NE

  E

  SE

  S

  SW

  W

  NW

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

  Probabilità

  Likely

  Dimensione

  1–1.5

  New snow is landing on top of a widespread hard and smooth crust that formed during this past weekend’s warm and wet weather events. This stout crust is found across all aspects, gradually thins with elevation, and will be a prime bed surface for new snow problems. As snowfall totals increase from a few inches to possibly over a foot today, managing sluffing on steep slopes will become increasingly important as these slides can knock you off your feet and drag you into terrain traps or other obstacles below.  Encountering Dry Loose avalanches will be most likely on wind sheltered slopes greater than 40 degrees. Mind slope angle today as you travel, be aware of harzardous features, terrain traps or anything else that might amplify the consequences below, and be prepared to bale into lower angle terrain if loose snow accidnentaly starts rushing down the hill with you.