Avalanche forecast

Swan Range

Flathead Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

Look for signs of wet and wind-affected snow as you climb into the alpine. You may find sensitive drifts in unusual locations. Move to less steep terrain if the snow surface cracks around your feet or machine or if you notice fresh rollerballs.

Avalanche problems

  • Wind Slabs

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

    A pulse of new snow combined with northeasterly winds will begin to build fresh drifts in unusual locations. These slabs will be thickest in areas favored by recent snowfall and winds like Glacier National Park, along the Continental Divide.  In such locations, it may be possible to find wind-drifted snow at middle elevations. Slides will run easily on the recent melt-freeze crust and may become more sensitive as temperatures increase throughout the day. 

    Look for wind-stiffened snow along ridgelines and in cross-loaded gullies. Identify these features by a scalloped surface or dune-shaped drifts. Cracking around your feet or machine indicates that slabs are sensitive to the weight of a rider and is a good reason to seek out less steep or more sheltered terrain. 

  • Loose Wet

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

    The possibility of natural and human-triggered wet loose avalanches remains due to new snow, warm temperatures, and potential sunshine. Any slides should be confined to the new snow and thus small in size.  Debris could travel faster and farther on recent melt-freeze crusts. Even a small slide can be difficult to escape and could result in injury or worse if you are carried over a cliff or raked through rocks and trees. 

    Rollerballs and pinwheels are signs that the surface snow is ripe for wet loose activity and should steer you towards less steep terrain. This problem will be slowest to develop on slopes that did not receive new snow.  

    (4/3/2024)

    We observed a couple larger piles of wet debris that came off of Mt. Penrose. These were large enough to injure a person, but likely not large enough to bury a person. 

    Photo: Cam Johnson

Avalanche Discussion

Today’s hazards will be driven by recent snowfall. Where you find 4+ inches of new snow, expect the danger rating to reach MODERATE due to the effects of northeasterly winds, warm temperatures, and some potential sunshine. Areas that received little to no new snow will see LOW danger throughout the day.

I’m telling you this because I’ve got some uncertainty regarding snowfall totals and distribution. It appears that recent precipitation favored Glacier National Park and the Continental Divide with 4 inches at Flattop Mountain and 5 inches at Marias Pass respectively. Beyond that, things get a little murky due to rapid snowpack settlement and a fluctuating rain/snow line. Key into new snow depths as you travel higher in elevation. Keep in mind that it only takes a little bit of available snow to form thick drifts in areas favored by northeast winds, like Aeneas Ridge which has recorded winds of 30mph or more since yesterday evening.

It’s been over two weeks since the last reported avalanche failing on weak layers buried 2-4+ feet deep. With another round of warming behind us, we’ve elected to drop the Persistent Slab problem in all zones. You can continue to reduce your risk by choosing slopes that have a stout crust in the top two feet or avoiding rocky terrain where the snowpack has variable depth.  

It's hard to believe it, but FAC's last daily forecast will be on Monday, April 8th 2024.  After that we will continue to issue conditions updates on Tuesdays and Fridays until May or as conditions dictate. 

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