Salt River and Wyoming Ranges

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

  1–2

  Though slopes in the Greys Zone remain challenging to access, recent snowfall has made riding in to access alpine terrain doable.  Yesterday, Frank noted temperatures above freezing at Smith Fork and small but widespread loose avalanche activity in the Snake River Canyon. Above 8,000 feet, the culprit weak layer in recent slides has been a several-inch-thick layer of faceted snow (additional surface hoar included in many locations, free of charge) buried 1.5-2+ feet deep. The distribution of this weak snow remains widespread, and the current sensitivity remains variable. You will most likely find them on slopes facing E-NE-N-NW above about 8000', but avalanches will not be limited to these aspects as the sun moves into play. Assume this layer exists and choose lower-angled slopes that are not threatened by steeper slopes above. You're more likely to trigger persistent slab avalanches in areas where the wind has stiffened the snow surface or formed drifts, but they are also possible in sheltered terrain. Explosive results at nearby ski areas are a great tell-tale sign of what a sled or human on a slope might do, and these results show extensive activity with 2-5 foot slabs and wide avalanches. With warming temperatures expected up to 10,000 feet, the first clear sign of an unstable snowpack may occur when you trigger a large avalanche. These types of slides can be triggered remotely—from a distance above, below, or to the side of a steeper slope.

  ADDITIONAL DISCUSSIONWarmer temperatures today could lead to wet snow slides and sluffs. These may not be limited to solar aspects as overall air temperatures are climbing. This will primarily be a lower elevation problem where enough snow exists but could creep into the mid and upper elevations. Given the potential for human-triggering, it remains best to stick to lower-angled terrain. Conditions will be most dangerous on middle and upper-elevation slopes during peak warming in the afternoon. Be alert to signs of changing and unstable snow, such as isothermal snow in the middle elevations or cracking and collapsing—these are obvious indicators you've found dangerous conditions.