Boletín de aludes

Whitefish Range

Flathead Avalanche Center
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Peligro de aludes

Sun
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 5 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

The storm may be tapering off, but up to 18" of new snow have stacked up over the past few days, and avalanches remain likely today—especially in wind-loaded start zones. These slides could easily bury or injure a rider and may trigger deeper, more destructive avalanches on buried weak layers. Enjoy the best snow of the season in low-angle terrain without steep slopes overhead.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1.5–3

    Up to 18 inches of new snow over the past few days likely amounts to 3–5'+ of wind-drifted snow in start zones that face NW-E-SE. This load is stressing the January Drought Layer (JDL—surface hoar and facets on a crust), which was still producing large and destructive avalanches prior to this storm cycle. This layer now sits roughly 2–4 feet below the surface in sheltered terrain, and even deeper on wind-loaded slopes. With a deep weak layer and a tapering storm, the likelihood of triggering a persistent slab avalanche will decrease, but the consequences are severe.

    Two main scenarios could produce an avalanche on the JDL today. The biggest concern is a slide that begins in the recent storm snow and steps down several feet to the JDL, producing a large and destructive avalanche. The other possibility is triggering an avalanche from a thin spot—often near rocky outcrops, the bases of trees, or locally wind-scoured areas—where the weak layer sits closer to the surface. Either scenario could produce an avalanche that would be difficult to walk away from.

    Avoidance remains the best strategy. Stick to low-angle terrain without steep slopes overhead. Fortunately, excellent riding conditions exist in this type of terrain, allowing you to enjoy the new snow while staying clear of this lurking dragon.

    (3/13/2026)

    A snowpit on a northeast aspect at 7000 feet displays the near-surface rain crust and the preserved surface hoar layer from the January Drought (JDL), buried at 75 cm. At this location, a rider's weight could still impact the buried surface hoar. Snowpit tests resulted in an ECTP 23 on the JDL.

    Photo: Mark Dundas

  • Wind Slabs

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

    Avalanches in new and wind-drifted snow are likely today. Continued loading, fresh north and east winds, and cold temperatures will keep slabs sensitive to a rider’s weight. While problems may exist in sheltered terrain, the most sensitive areas will be wind-loaded start zones where two types of wind slabs are the primary concern.

    Flavor 1: New Wind SlabsFresh wind slabs will form in real time today, especially on slopes that are usually wind-scoured, such as those facing west. If you see blowing snow, assume slopes downwind are being actively loaded. Shooting cracks are a clear sign of instability, but if a slope is being loaded, that’s reason enough to move on to another slope.

    Flavor 2: Older Wind SlabsWinds have eased significantly since their apex overnight Wednesday into Thursday, allowing softer, lower-density snow to cover older, harder wind slabs on slopes facing NE–E–SE. This softer snow may hide the usual visual clues, like textured surfaces or pillowy deposits. You can dig a quick hand pit to feel for a buried harder slab capping softer snow. Because these slopes also host the persistent slab problem, the safest choice is to avoid steep start zones on shaded aspects.

    Dry Loose:

    Expect sluffs in the new snow if you are riding on steep slopes today. With a lot of soft snow on the surface, some of these could grow large as they descend.

    (3/9/2026)

    Recent blowing snow has formed slabs of wind-drifted snow on the slopes below ridgelines on typical leeward aspects. Today's atypical winds will form slabs on terrain normally scoured.

    Photo: Michael Reavis

Avalanche Discussion

Additional snowfall today should do little to change avalanche conditions, but it will continue to improve the already excellent riding conditions. The bigger question mark is the effect of arctic winds from the north and east, which may create a new wind slab problem on slopes that don’t typically see wind-loading.

Poor visibility and limited observations leave some uncertainty about how widespread natural avalanche activity was during this multi-day storm. We suspect a natural cycle occurred in the Flathead Range, and possibly the Swan as well. Near Whitefish Mountain Resort on Thursday, the new snow proved sensitive, with numerous rider-triggered avalanches and productive mitigation by WMR Ski Patrol. Encouragingly, none of those slides were reported to have stepped down into deeper weak layers.

Two FAC teams toured yesterday, choosing low-angle terrain where they found excellent powder conditions and no obvious signs of instability. However, in the central Whitefish Range, the January Drought Layer (JDL) produced propagating results in an extended column test, reinforcing the need for continued caution.

The good news is that avoiding avalanche terrain today doesn’t mean sacrificing good snow. Phenomenal riding conditions can be found on low-angle slopes and in mature, closed-canopy forests.

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