Flathead Range & Glacier NP

Problèmes avalancheux

• 

  Wet Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Unlikely

  Taille

  1.5–3

  Last week's rain and warm temperatures allowed meltwater to move through the snowpack to buried weak layers, resulting in large wet slab avalanches. Recent cooling temperatures and dry conditions have slowed the movement of this free water.  This morning's surface crust will limit production of new meltwater from today's strong sunshine. However, there remains plenty of wet snow beneath the newly formed crust, and the potential for a large avalanche remains.

  Although unlikely, riders can trigger a large wet snow avalanche after the surface crust breaks down or in locations where it does not exist.  If you find yourself sinking into a mushy surface, move to a shadier aspect or a lower-angle slope to minimize your chances of initiating a slide. Natural avalanches are not expected, but you can limit your exposure by reducing the time spent on or under steep, open slopes later in the day. This is especially true of those harboring large cornices, where a falling block could trigger an avalanche deeper in the pack.

  Saturday's short-lived sunshine initiated rollerballs in recent storm snow. With more sustained solar expected today, anticipate this problem moving up in elevation. Associated wet loose slides should be harmless unless they knock you off your feet and push you into an area where you shouldn't be, such as tree stands, cliffs, or gullies.

   

  

• 

  Glide Cracks

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Unlikely

  Taille

  2–3

  Area SNOTEL stations report modest SWE loss over the past few days, indicating water is moving through the snowpack. Where the water reaches the snow and ground interface, weakening occurs. If a glide crack is present, a large destructive avalanche involving the seasonal snow cover could occur. Two glide avalanches occurred in the Swan Front on Saturday, the first of this type of avalanche in many weeks.  

  Today's sun and warming temperatures keep this as a potential problem. The surface crust at mid-elevations is thin and weak and will break down quickly, possibly allowing meltwater to continue migrating toward the ground. 

  Predicting whether and when these unusual avalanches will occur is difficult at best. The best way to mitigate this problem is to avoid traveling beneath slopes that harbor glide cracks. Although found on all aspects and elevations, these cracks appear to be concentrated on sunny slopes at mid-elevations.