Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 8 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

You might be able to trigger a slide large enough to hurt or bury you on steep, upper-elevation slopes with more than about 6 inches of new or drifted snow sitting on a supportable crust. Hard, dense drifts on steep slopes pose a Wind Slab avalanche hazard. Rollerballs fanning down slope indicate a Loose Wet avalanche hazard.  Both hazards may grow more widespread if more than a few inches of snow falls today.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Weather stations have recorded southwesterly winds most of the past two days. For better or worse, there's not that much snow available for transport. So there's no widespread Wind Slab avalanche Hazard. On isolated slopes with more than about 6 inches of drifted snow, you may be able to trigger slabs large enough to bury or injure you.

    Pay attention to the snow surface as you climb into upper elevations. Check for dense or hard drifts sitting on hard crusts by probing or digging shallow holes. Shooting cracks on snow like this is a sign these slabs are unstable. Avoid traveling under steep start zones where you see blowing snow and active loading. Dropping cornices can be a good way to check the stability of slabs on the slopes below.

    (12/14/2025) Debris from a cornice that didn't trigger a slab on the slope below.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1–1.5

    The potential for triggering sluffs of wet snow exists on steep slopes with more than about 6 inches of recent snow sitting on a supportable or slick crust. Terrain with these conditions is isolated to the uppermost elevations. The hazard could become more widespread this afternoon, if a few inches of new snow is followed by rain as freezing levels skyrocket.

    Watch for rollerballs fanning downslope from your boards or machine. These are a sign that wet snow avalanche hazards exist. Be alert for rapidly changing conditions, particularly intense snow showers that abruptly change to rain. 

    (12/14/2025) Refrozen wet avalanche debris at upper elevations in the Lake McDonald Valley. Fresh, soft rollerballs like this indicate a wet snow avalanche hazard.

Avalanche Discussion

Today, the places you can find trouble are limited to steep slopes where you find more than a few inches of recent or drifted snow over a hard crust. Those conditions are isolated to upper elevation slopes, thanks to unseasonably high snow lines in recent storms. This elevation band has also seen strong winds, with banners of blowing snow reported Sunday near Marias Pass. 

The combo of recent snow over a crust creates the potential for wet loose avalanches. However, it'll take more than about 6 inches of recent snow over a crust for wet loose avalanches to be large enough to be dangerous. Steep slopes with those conditions are isolated to the uppermost elevations. 

Similarly, recent snow is the raw material for wind slabs, and slabs of drifted snow more than about 6 inches thick can pose a hazard. However, these too are isolated to the lee sides of ridges and summits at upper elevations. There is more terrain like this in the Flathead Range, so we've listed a Wind Slab hazard there. Sunday, a party in on Mt. Brown reported sensitive cornices, but the debris didn't trigger slabs on the slopes below. 

The region may see a few inches of new snow this afternoon, before snow lines skyrocket to 7000 feet or higher again. Some of that snow may come in high-intensity showers. If the spot where you're traveling experiences high-intensity showers, the Loose Wet and Wind Slab avalanche hazards may quickly become more widespread. Be alert for rapidly changing conditions. Watch outs include rain on new snow and blowing snow. Respond to these by stepping back to less steep slopes clear of overhead start zones. 

A second pulse of moisture and a cold front on Wednesday could create winter-like conditions in time for the Winter Solstice. That's a concept.

Also, bears. Still about. 

Regions covered