Boletín de aludes

Swan Range

Flathead Avalanche Center
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Peligro de aludes

Thu
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 3 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

New snow and strong winds have created dangerous avalanche conditions. Triggering an avalanche failing 1 to 3 feet deep is likely. Avalanches may fail naturally and run long distances. Enjoy the fresh snow today by sticking to low-angled terrain that is free of overhead hazards.

Problemas de aludes

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    While seeking out terrain sheltered from the wind, pay close attention to signs of cracking and collapsing. If you feel or see these signs, choose terrain less than 30 degrees in steepness. Storm snow is piling up deep and may rest on persistent weak layers. The distribution of these weak layers is not clear yet. Slabs may break wide distances and be triggered remotely.  

    (1/7/2024)

    Storm Slab in the Swan Range. This avalanche failed on a facet/crust buried in late-December. 

    Photo: Kaleb Retz

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1.5–2.5

    You can find better and safer riding in wind-sheltered terrain. Extreme winds out of the southwest drifted new and recent snow into thick hard slabs. Expect to find slabs of drifted snow near ridgelines, saddles, and cross-loaded gullies further downslope. Hard slabs are notorious for breaking far uphill and being very difficult to escape. Winds will shift to the east today, which makes finding areas sheltered from the wind more difficult. Avoid areas where you see blowing snow and dune-shaped drifts.

    (1/8/2024)

    Terrain loaded by westerly winds. This avalanche failed on an east facing slope at roughly 7000 feet. The blue line marks the crown line. 

    Photo: Cam Johnson

Avalanche Discussion

Multiple small to large (D1-D2) avalanches have been reported since this past weekend. Slab avalanche activity has occurred on most aspects above 6000 feet. Yesterday (Tuesday), Ski Patrol at Whitefish Mountain Resort reported triggering slides that ranged from 5 to 30 inches thick. Some avalanches were remotely triggered and propagated wide distances. Avalanches also failed as low as 5300 feet in elevation, which is far lower than we have experienced this season.

Wind speeds yesterday made up for the last few weeks of calm conditions. Tunnel Ridge in the Flathead Range clocked a gust of 103 mph! Average wind speeds ranged from 15 to 30 mph throughout the forecast area. These speeds are prime for drifting new and recent snow into hard slabs. Winds will shift to the east today, and drift snow onto aspects that typically don’t get loaded by the wind. Pay close attention to surface clues and active wind transport.

Precipitation totals are starting to stack up. Below are the totals since January 4th:

  • Stahl (northern Whitefish Range): 3 inches of water
  • Flattop (central Glacier National Park): 2.8 inches of water
  • Noisy Basin (Swan Range): 3.5 inches of water

Except for yesterday, most of the snow has been low-density. This led to impressive snow totals throughout the forecast area. Temperatures crept up into the mid-twenties at 6000 feet yesterday. Rising temperatures and denser snow caused some remote weather stations to settle faster than snow accumulated. This rapid settlement and upside-down new snow may have formed the slab that we were missing earlier in the storm. Pay close attention to cracking and collapsing in the snow. 

An arctic air mass will drop temperatures to below zero tonight. Frigid temperatures increase the consequences of a small injury or broken equipment. The avalanche conditions are dangerous, and so is the weather. Plan short and simple days.

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