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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Highlights

You're unlikely to trigger avalanches today if you navigate two isolated avalanche problems. The first is the potential to trigger hard slabs on shaded slopes. The second is shallow pockets of drifted snow in leeward and cross-loaded start zones. Both problems grow more widespread as you gain elevation. You can minimize your chances of stumbling into either by sticking to lower angle terrain clear of overhead hazards. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–3

    Soft, weak snow still exists 2 to 3 feet below the surface. You can still trigger slabs that break on these weak layers on isolated slopes at mid and upper elevations. The suspect slopes didn't avalanche recently and aren't capped by a supportable melt-freeze crust. These weak layers formed in January, and will be closer to the surface - and easier to collapse - on slopes where scouring and drifting tend to leave variable snow depths. 

    Digging into the snow and testing the weak layers is the only way to determine whether a Persistent Slab avalanche structure exists in the terrain where you're traveling. You've likely found the hazard if your tests produce propagation or sudden collapses. Tests, plural, so you're less likely to succumb to confirmation bias or misinterpretation. 

    Slabs that release on the January weak layers can break surprisingly wide and connect multiple start zones. Falling chunks of cornice can trigger natural avalanches. The most straightforward way to minimize your exposure to this hazard is to stick to low-angled terrain that's not threatened by steeper start zones above.

  • Wind Slabs

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

    You can trigger pockets of drifted snow on leeward and cross-loaded slopes at upper elevations. These can pose a hazard where they're more than about 8 inches thick or above a terrain trap. That's not many locations; there's not been much snow available for transport since midweek. 

    Look for isolated slabs of wind-packed snow top-loaded onto steep start zones near ridges, or cross-loaded into chutes and gullies downslope. They may lure you into trouble because they might be the softest, deepest snow on the surface. They don't make good candidates for slope cuts when they're hard, because they can break above you. 

    (3/8/2025)

    Blowing snow near the summit of Elk Mountain. Winds were strong with some extreme gusts above about 6500 feet. There was only a few inches of recent snow available for transport, so actual slab formation is likely limited. 

    Photo: blase reardon

Avalanche Discussion

Cloud cover kept wet snow avalanche hazards at bay Sunday, though it may also have allowed melting at the surface of some shaded mid and upper elevation slopes. These may be capped by a breakable crust this morning. Elsewhere, the snow surface consists of refrozen wet snow that's hard and slick. Falling and sliding may be the most serious hazards in steep terrain.  

The weekend has been marked with powerful winds, mostly blowing from the south and west. They haven't had much soft snow to work with, so I expect any slabs that formed are shallow and isolated. You're most likely to find these on leeward (northwest -northeast - southeast), upper-elevation slopes. The gusts may have cross-loaded some slabs into gullies and chutes well below ridges. Before committing to steep terrain where these exist, assess the consequences of getting carried downslope. Trees, rocks, and gullies can exaggerate the consequences of otherwise minor rides. 

Evidence that the January weak layers have strengthened is gradually accumulating. Rob and Lydia had propagating test results in the central Whitefish Range Friday, and Lydia also reported propagation in the northern Swan on Wednesday. Reports from the WMR sidecountry include propagation Thursday but not Sunday. No recent obs have described collapses or shooting cracks. At this point, slope-scale assessments are needed to help you asses the potential to trigger slides on the January weak layers. That means digging to check whether facets and surface hoar are preserved within a meter or so of the snow surface, and whether these produce propagation or collapses in tests. Tests are less reliable on slopes with variable snow depths and/ or a convex profile, because of snowpack variability. 

We've had no reports of recent glide avalanches. It's still worth staying out from under open cracks, because gravity, like rust, never sleeps; the slabs below the cracks are still creeping and gliding downslope. The most recent tally of cracks on the west side of the Swan Range is up to 39. 

While all of the above hazards are isolated, they sometimes overlap, and choosing terrain that minimizes one might expose you to another. That makes travel a little complex, and thus the Moderate danger at upper elevations.

Should you want to free your heel - on the downs - check out Telefestivus at Blacktail Ski Area on Saturday, March 22 and Sunday, March 23. In conjunction with the mind-freeing event, Tamarack Brewing will host a fundraiser with a raffle and film for the Friends of the Flathead Avalanche Center from 5 to 8 PM Saturday, March 23. 

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