Bollettino valanghe

Swan Range

Flathead Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 5 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

An early exit will be key to enjoyable and fun riding today. Rain forecast this afternoon will abruptly increase the chances of small, wet loose avalanches. It will gradually increase the potential for destructive slabs as it percolates into deeply buried weak layers. Plan to be off of and out from under steep start zones with more than a few inches of recent snow by about midday. 

If more rain falls than forecast, the avalanche danger may rise to Considerable overnight.

Problemi valanghivi

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    We still have a lingering danger of large to very large natural avalanches releasing as meltwater weakens deeply buried weak layers. This hazard is generally confined to upper-elevation slopes where there's a weak melt-freeze crust near the snow surface. Or that were too high for a crust to form. 

    Rain this afternoon will increase the likelihood of slabs releasing naturally, though it will take some time for water to percolate to these deeply buried weak layers. Any releases should be isolated - many upper elevation slopes have already avalanched. Nonetheless, it would be prudent to avoid traveling in or below steep start zones, even those well above you. 

    (3/23/2026)

    avoid traveling under terrain like this today. While the crown is older, it's a good indication of the threat posed by the lingering wet slab avalanche problem.  7500 feet, northerly slope.

    Photo: Flathead Avalanche Center

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Natural and triggered sluffs of wet snow will grow increasingly likely as the day progresses and rain falls in the mountains. They'll involve more snow as you climb higher in elevation, with some slides at upper elevations involving enough snow to carry you over or into a terrain trap. I expect them to run far on the underlying melt-freeze crust. 

    Time your travel today to be off and out from under steep start zones with long, continuously steep tracks by midday to early afternoon. Waiting until rain starts probably won't give you much time to get out of the way. Rollerballs fanning downslope are a clear precursor to these slides. 

    (12/31/2025)

    Rollerballs that start in steep terrain, such as this one, can accumulate large amounts of snow and grow into larger avalanches as they move downhill.

    Photo: Guy Zoellner

Avalanche Discussion

In professional wrestling, a dramatic way to end a match is by diving or jumping off the ropes onto an opponent. Today's avalanche dangers mostly come from above, with us travelers as the hapless wrestler on the mat. Unlike those matches, however, the ending today isn't scripted. You can avoid the diving drops and sentons of wet snow avalanches by staying out from under steep start zones - particularly those high above you and capped by large cornices. 

Saturday's snow left a trace to maybe 4 to 6 inches of snow on top of a melt-freeze crust. At mid-elevations, the crust is stout and supportable, with only a few inches of new snow above it. That's not enough snow for loose wet avalanches to entrain much debris, so at these elevations you're unlikely to trigger or encounter sluffs of dense, wet debris large enough to bury or hurt you, unless they carry you into a terrain trap. The stout crust makes it unlikely you'll trigger a large slab that releases on a deeply buried weak layer, and it should slow the percolation of melt and rainwater to those layers.

Conditions change pretty noticeably right around 6500 feet - give or take, depending on the site. The melt-freeze crust is weaker and thinner. It's capped by up to six inches of recent snow. So there's enough snow for larger, more dangerous wet loose avalanches once the rain starts. More significantly, the crust doesn't reduce a rider's chances of affecting those deeply buried weak layers or slow infiltration of water.

The bottom line, then, is to stay off the mat and out from under anything that can fall on you from above. 

Regioni coperte