Bollettino valanghe

Flathead Range & Glacier NP

Flathead Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 7 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Although it is unlikely to trigger a large avalanche that fails into old snow, the consequences if caught remain severe. Hedge your bets on slopes with long, smooth runouts. Only expose one rider to steep slopes at a time. Choose lower-angled slopes to avoid the problem altogether.

Problemi valanghivi

  • Persistent Slabs

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

    The chance of triggering a large slab avalanche failing 1 to 3 feet deep is unlikely, but not impossible. The last human-triggered avalanche failing on buried weak layers was 9 days ago. Here are a few bullets to help you navigate this problem:

    • Traveling on slopes with a supportable crust significantly reduces the chances of collapsing the weak layer and causing an avalanche. A hard crust exists on sunny slopes and most mid-elevation slopes. Observations indicate thinner crusts on upper-elevation, shaded aspects.
    • A snow machine is more likely to cut through surface crusts and collapse buried weak layers. Add a wider margin if you want to ride in avalanche terrain on your machine.
    • If you want to step out into avalanche terrain, then I recommend being selective with which slopes you choose. Choose slopes that have runouts free of trees, cliffs, or gullies. This will reduce the chances of trauma if the unexpected happens.
    • If you don’t want to tango with this problem at all, then continue to choose lower-angle slopes.

    (1/16/2026)

    A large, natural slab avalanche on Slippery Bill Mountain in the Skyland area. (7300' - NE - D3). This likely failed on a buried weak layer.

    Photo: Michael Reavis

Avalanche Discussion

The weather forecast today should not affect snowpack stability. Surface conditions are either firm or punchy. Riders are generally finding poor travel conditions.

You may notice we downgraded the likelihood from possible to unlikely for the persistent slab avalanche problem and kept the avalanche danger rating at Moderate. Why is this? Simply put, the size of avalanches and travel advice just don’t fit within the level 1 (low danger) box right now. Although it is unlikely, IF someone triggers a slab avalanche failing 1 to 3 feet deep, it is going to be difficult to escape, and the consequences can be severe. I expect that with continued high pressure, we may see low danger soon, but an avalanche problem that has produced very large avalanches warrants time and respect.

We dropped the likelihood for two main reasons. The first is the time since the last reported sign of instability, and the second is the spatial distribution. The last human-triggered avalanche was on January 11th, and the last documented avalanche is estimated to have failed on January 12th. We have received no reports of collapsing since then. The other component is that the spatial distribution of the problem becomes less with the presence of surface crusts. Supportable surface crusts reduce the likelihood of collapsing a buried weak layer. Observers are consistently finding supportable crusts below 6000 feet. Above 6000 feet, surface crusts range from breakable to supportable depending on aspect.

Education offerings:

Human-powered partner rescue clinic, January 24. Find out more details here. 

Ladies' human-powered Intro to Avalanches January 29 and 31. Get more details here.

Regioni coperte