Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 9 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

The avalanche danger will rise through the day, as slabs of new and wind-drifted snow thicken. The most dangerous slopes will be on the downwind sides of ridges, saddles, and other terrain that collects wind-blown snow. Plan to be increasingly cautious as the day progresses, pay attention to snow totals, and avoid steep slopes where you find dense slabs 6 inches or more thick. 

The danger may rise more rapidly if snow totals today exceed forecasts or if  snow turns to rain sooner than forecast.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5

    With a forecast for moderate to strong southwest winds and 3 to 8 inches of snow today, dense slabs of new and drifted snow to pose today's primary hazard. These will be larger at upper elevations, where more snow is available for transport. They'll be thickest on the leeward sides of ridges, downwind of saddles and passes, and where snow is cross-loaded into gullies and chutes. They can be dangerous where they're more than about six inches thick.

    Avoid riding steep slopes where you find these conditions. Don't linger under steep start zones where you see signs of active wind loading, like plumes or whirlwinds of blowing snow. Or hear strong winds above you when visibility is poor. 

    At mid elevations, this hazard will be more localized, with slabs generally smaller. 

    (12/7/2025)

    What a thin slab of drifted snow will look like underfoot. 

    Photo: Michael Reavis

Avalanche Discussion

If you want to get a feel for conditions in the mountains over the next few days with minimal effort, ride through an automated carwash in a convertible with the top down. You'll get the waves of moisture and the warm wind forecast through the week at mid elevations. Ignore the brushes; they don't fit this analogy. I can't, however, think of a quick substitute for conditions above about 7000 feet, where all that subtropical moisture will fall as snow. Feet of snow. 

That means increasing avalanche danger, with overlapping and rapidly changing avalanche problems that will make for complex travel. The danger will increase with elevation; where the precipitation comes as snow, expect thick slabs of new and drifted snow to pose the primary hazard. That's mostly going to be near ridgelines and summits above about 6500 feet. Where the rain/snow line is bouncing up and down - about 5500 to 7000 feet - the hazard will likely toggle from Storm Slab to Loose Wet snow problems and back. 

All that makes for complex travel, where you'll need to plan for and mitigate different avalanche problems as you change elevations and aspects, and as the storms develop. Focus on the key signs of danger and instability - shooting cracks, fresh avalanches, roller balls fanning downslope, and slabs of dense, drifted snow overlying softer snow. I'd also be leery of traveling under steep start zones with active wind loading - which may be a thousand feet or more above you - and steep chutes during periods of rain-on-fresh-snow. 

As of now, we don't have much evidence of widespread buried persistent weak layers.  The region hasn't seen conditions favorable for formation of these layers. People aren't reporting basal depth hoar or facet/ crust combinations from snow profiles, or propagating column tests failing on layers like these. Observations have been limited, especially at upper elevations. 

 

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