Bulletin d’avalanche

Swan Range

Flathead Avalanche Center
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Danger d’avalanche

Mon
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 9 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Bountiful recent snowfall and increasing winds continue to develop dangerous avalanche conditions in the Swan Range. Slabs will be found on all aspects above 5000 feet, but will be thickest and most hazardous in wind-drifted snow. Cracking under your skis or machine indicates you have found a sensitive slab. 

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    Several days of heavy snowfall in the Swan Range have already produced natural avalanches (image to the right or below). Now that the southwesterly winds have returned, the danger remains elevated. There is plenty of snow available for transport, and we expect fresh slabs to develop and thicken through the day. 

    Slabs will become thicker and more widespread as you gain elevation. The largest and most dangerous features will be found in wind-drifted terrain, where it is likely that you could trigger a slide.  Avalanches at the surface could step down into the foot or two of recent snow, producing a much larger slide. 

    Cracking or collapsing indicates you have found an unstable slab, directing you to a lower-angle slope.

    (12/6/2025) Photo: CJ Cummings

    This soft slab avalanche failed during the recent heavy snowfall in the Swan Front. This is the size and type of slide you could trigger today in sheltered terrain. 

Avalanche Discussion

Snowfall over the past few days boosted our low snowpack and improved riding conditions at all elevations. Surprisingly, the recent series of storms arrived without much wind, preserving light surface snow in most locations. 

Light to moderate southwest winds with strong gusts returned overnight and will persist through the day. Fresh wind slab formation will be the primary concern in the Whitefish and Flathead/GNP zones.  A storm slab problem remains in the Swan Range, with thicker and more widespread slabs found in wind-loaded terrain. 

The Swan Range was favored with 2.4 inches of SWE since Thursday, which resulted in a CONSIDERABLE danger rating on Saturday. A party visited the Swan Front and noted thin slab avalanches in the new snow that may have stepped down to the ground. They also saw evidence of wind loading and shooting cracks in the snow surface.

Observations remain limited, but the new snow seems to have bonded well with the old snow surface in many locations. Saturday, WMR ski patrol found limited evidence of surface slabs during their control routes. I visited the side country just east of the resort and found a generally soft, loose snow surface. Mike was in the Flathead Range, where, unsurprisingly, he found travel difficult due to the infamous Middle Fork alder fields. An experienced recreationalist traveled to southern Glacier Park, where he noted thin conditions, with just the past couple of storms comprising the snowpack. 

A potent and messy series of warm, wet, and windy storms is on tap to impact the Flathead tonight through Wednesday. Expect dangerous avalanche conditions to develop this week!

 

Régions couvertes