Boletín de aludes

Swan Range

Flathead Avalanche Center
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Peligro de aludes

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

Lo esencial

Shifting winds have drifted snow on all aspects. You could trigger a slide in wind-blown snow in both usual and unusual locations. Steer away from slopes with a rippled surface or dune-shaped features.

Problemas de aludes

  • Wind Slabs

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

    Expect to find several flavors of wind slabs today. Yesterday (Thursday) observations reported moderate to strong Southwest winds and light to moderate blowing snow. Riders found slabs 2 to 10 inches thick on exposed upper-elevation slopes facing north through east.  In some areas, these slabs were soft and sensitive.  In others, they were hard and unreactive.  

    Winds shifted to northeasterly this morning and will drift snow on slopes facing south through west.  Expect to find fresh slabs forming in unusual locations throughout the day. Slabs that are 8+ inches thick will be difficult to manage.  Drifts that form on top of crusts or weak snow may be more sensitive.

    Blowing snow, rippled surfaces, or dune-shaped features are clear signs of wind effect.  Look for these hallmarks along ridgelines, near saddles, or in cross-loaded gullies.  Cracking around your feet or machine indicates that drifted snow is sensitive to the weight of a rider and should usher you to less steep or more sheltered terrain. 

    (1/16/2025)

    Intentionally skier-triggered wind slab at 6500 feet on an east aspect in Snowslide Creek. 

    Photo: Ryan Minton

Avalanche Discussion

It wouldn't be winter in Montana without at least one Arctic intrusion.  Our first of the season is slated to arrive today. The coldest temperatures won't set in until later this weekend but consider building out your cold weather kit with some extra layers, hand warmers, etc. Here are a couple of things to keep in mind on this transition day:

  1. The northeasterly winds accompanying Arctic air will expand wind slab formation to atypical (south through west) slopes. These winds are channeled by topography as cold air spills over the continental divide and can wreak havoc at mid- and lower elevations along the Highway 2 corridor, the southern end of the Whitefish Range and the western front of the Swan Range.
  2. We're getting daily reports of glide cracks (obs from southern GNP) and glide avalanches (obs from Swan Range) on southerly aspects throughout the advisory area.  While the failure mechanism for these slides is not well understood, there is some history of glides releasing following a cold front.  Regardless, the travel advice remains simple: stay off and out from under slopes sporting the "brown frown."

Education and Events:

Check out our events calendar.  There is a Motorized Intro to Avalanches course on Saturday, January 25th.

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