Avalanche forecast

Swan Range

Flathead Avalanche Center
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Avalanche danger

Thu
Alpine
1 · Low
Treeline
2 · Moderate
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Out of date — this forecast expired 8 months ago.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

This morning, expect generally stable avalanche conditions. Steer around isolated slabs of drifted snow downwind of ridges and saddles at upper elevations. Only expose one rider to steep terrain at a time.

The avalanche danger will rise this afternoon and overnight if we see rain on snow. Pinwheels and rollerballs are precursors to a loose wet avalanche cycle. Stay out from underneath large avalanche paths if you feel rain or see signs of wet snow. 

Avalanche problems

  • Loose Wet

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

    Increasing temperatures and rain on snow will wet the snow surface and cause it to avalanche. Existing dry snow above a smooth crust will wet easily, and avalanches may run relatively far distances. Avalanches should generally be small, but can hurt you if you get knocked off your feet in consequential terrain, or hit from above. Rollerballs and pinwheels are signs of an impending wet loose cycle.

    Travel Advice: Precipitation should start late this afternoon, so it may be best to plan an early exit. Track surface conditions and adjust your terrain selection and minimize exposure to overhead hazard as soon as the snow surface shows signs of wetting. Plan a route that avoids traveling through large avalanche paths in the afternoon.

    (12/14/2025)

    Multiple piles of dirty, wet debris on the south-southeast slopes in Rescue Creek. These failed during the Atmospheric River. 

    Photo: Josh Lipkowitz

  • Wind Slabs

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

    Your chances of triggering slabs of wind-drifted snow are diminishing. Although the likelihood has gone down, we remain wary of wind-loaded slopes at upper elevations, because of the potential consequences. If triggered, hard wind slabs are difficult to escape.

    Travel Advice: Identify and go around dune-shaped drifts or sculped-looking surfaces downwind of saddles and ridges at upper elevations. Test their sensitivity by stomping or riding on small wind features in inconsequential terrain before committing to larger terrain. Have a spotter and hedge your bets on terrain with smooth, clean runouts. Better riding conditions are found in terrain sheltered from south and west winds. 

    (12/7/2025)

    Common example of windloaded terrain along the Continental Divide from strong West winds with snow available for transport. 

    Photo: Michael Reavis

Avalanche Discussion

Observations over the past several days show no signs of instability. Observers continue to find stubborn, unreactive slabs downwind of ridges, with clues of more significant wind loading in exposed, alpine terrain. The last human-triggered avalanche was 4 days ago on December 20th. Triggered avalanches were up to a foot thick but did not propagate wide distances. Avalanches were small, and evidence suggests they are becoming unreactive to triggers. Blase describes the current wind slab problem and what to look for in this video (also below).

Increasing temperatures and a chance of rain today will be the primary weather factors contributing to changing avalanche conditions. Plan an early exit since rain is forecast to start late this afternoon. The rain/snow line should hover around 6500 feet, so I’d expect to see the most activity at middle elevations. There simply isn’t enough snow at low elevations for a hazard to exist, and forecasts indicate only an inch or two of snow above 6500 feet. 

Of note, several parties have recently found facets above the mid-December crust. The interface generally exists about 1 foot below the surface and deeper in wind-drifted areas. Evidence exists in all three forecast zones, although the precise distribution is still unclear at this point. Currently, we don’t expect them to pose much of a problem with the lack of a slab above the facets, and warm temperatures should help them strengthen. Moving forward, this will be an interface to pay close attention to. 

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