Soldier & Wood River Valley Mtns

Problèmes avalancheux

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  2–3

  The weak snow buried near the ground continues to be the primary avalanche concern in this zone. While encountering a wind slab (Problem #2 below) is more likely in the western part of this zone, any wind slab you trigger has a chance of "stepping-down" to the weak snow near the ground. Some recent human-triggered and natural persistent slab avalanche activity:

  • Saturday, a rider between Wells and Dollarhide Summits triggered an avalanche on a steep, heavily wind-loaded slope (photo at right).
  • Saturday, a skier on Titus Ridge intentionally triggered a large avalanche. The slide initiated as a stiff wind slab that formed during last week's wind event and then "stepped down" to the December weak layer. Photos and more details are available here. Ben investigated this event (video).
  • Sunday, Sun Valley Heli reported seeing a recent large, natural avalanche that failed near the crest of the Smoky Mtns north of Dollarhide near Baker Ck divide, likely involving this weak snow (photo here).
  • An observer reported fairly recent natural avalanche activity in the Pioneer Mtns west of Grays Peak.

  The depth of the snowpack is highly variable in this zone. In areas where the snowpack is less than about 4 feet deep, the weak layer is much more "accessible" to a skier or rider. This makes triggering slides easier. Strong NW winds over much of the past 10 days have scoured many slopes (bringing the weak layer closer to the surface) and deposited hard slabs on others (adding weight to the weak layer).

  So what sort of areas should you be most worried about right now? The avalanches described above share some characteristics:

  • Slopes steeper than about 35 degrees
  • Wind-loaded terrain
  • Rocky slopes with a thinner snowpack

   This is exactly the type of terrain where you are most likely to encounter this problem today. Recent snowfall has hidden signs of wind events in places, making it more difficult to tell when you're on previously wind-loaded slopes. This fact has made many experienced skiers and riders think twice about entering consequential avalanche terrain, despite the gradually decreasing danger. 

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  1–2

  Soldier Mtn Cat Ski staff triggered wind slab and storm slab avalanches in very steep terrain in recent days. They report the slides are running on the hard, wind-hammered surface beneath the recent snowfall. These relatively small slides can have big consequences if they carry you through rocky, treed terrain or push you down into a terrain trap like a gully or a creek bed.

  From an avalanche danger perspective, the larger concern is still the additional loading on the persistent weak layers described in Problem 1. Small wind slab avalanches can be great triggers for more deeply buried weak layers. Any avalanche that steps down to these persistent weak layers will be large and destructive.