Flathead Range & Glacier NP

Problemas de aludes

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta montaña
  • Límite del bosque
  • Bajo el límite del bosque

  Probabilidad

  Possible

  Tamaño

  1–2

  Cold, dry snow is widespread in the mountains, and any slope that sees direct sun today may produce loose avalanches as surface snow warms (dry or wet). Cloud cover is the wild card and will determine where this problem occurs. Meanwhile, southwest- and west-facing slopes may have already seen some melting from Saturday afternoon’s sunshine, while east-facing slopes could be seeing their first exposure to sunlight this morning. 

  Managing this problem is fairly straightforward. If the sun is shining on the slope you are on—or on slopes above you—expect the potential for snow tostart shedding and move to lower-angle terrain or switch aspects and step into the shade. Snow falling from trees, rollerballs, pinwheels, or soggy surface snow are good signs that loose avalanche problems may be developing. Keep in mind that snow on rock bands, cliffy features, and high above you can warm and release before the snow at your feet does. Even small wet loose avalanches can entrain significant snow and have serious consequences if they knock you off balance or push you into terrain traps.

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta montaña
  • Límite del bosque
  • Bajo el límite del bosque

  Probabilidad

  Possible

  Tamaño

  1–2

  Recent light, dry snowfall continues to be transported by south-southwest winds, forming fresh slabs. These features may disguise several generations of slabs built over the past week. You will find these near and below ridgelines, in mid-slope gullies, and behind terrain features such as rock outcroppings and ribs.

  Recent cornice growth has been impressive, increasing the chance of a triggered slide on the slope below, as noted by observers in the Swan yesterday.

  Signs that wind has affected an area include textured snow surfaces (attached image), dune-shaped drifts, and cornices. The surface will feel noticeably firmer than in more protected areas. 

  Cracking underfoot or a sled indicates you have found a slab. Collapsing and cracks that shoot away from you confirm the slab is sensitive. If you encounter a dense surface over softer snow, choose a lower-angle slope to increase your safety margin.

  

• 

  Persistent Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta montaña
  • Límite del bosque
  • Bajo el límite del bosque

  Probabilidad

  Possible

  Tamaño

  1.5–2.5

  Triggering a 1-3 foot thick slab avalanche on a buried weak layer remains possible. Three rider-triggered slides occurred on this layer in the Whitefish Range over the past few days. 

  The conditions for a Persistent Slab avalanche are not present on all slopes, and it's challenging to determine where they are or aren't. The safest bet is to assume that the troublesome slab/weak-layer/crust combination exists on all slopes. You may or may not experience obvious signs of instability—snowpack collapsing or cracks shooting out from your skis or sled—before triggering an avalanche. The resulting slides may propagate farther than expected, resulting in a large avalanche.

  Friday's hard slab avalanche was triggered remotely from the side of a steep slope. This could also occur from lower-angle terrain above or below a steep slope.

  Reduce your chances of triggering one of these beasts by selecting low-angle slopes not connected to steeper terrain.