Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

An afternoon storm could quickly increase the avalanche danger. Cracking around your feet or machine means you can trigger an avalanche on steep slopes. Move to low-angle or wind-sheltered slopes if you notice blowing snow. 

IF the incoming storm arrives earlier or stronger than forecasted, expect the danger to rise to CONSIDERABLE at upper elevations.

Avalanche problems

  • Storm Slabs

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

    Riders have triggered multiple small slab avalanches in the southern Whitefish Range during the last two days. Roughly one foot of snowfall from this week may be upside-down, with heavier snow resting on top of a less dense layer. In some locations, the recent snow was deposited on thin crusts or weak layers (including facets and surface hoar) and may be more sensitive.

    Slabs will be thicker, more widespread, and most sensitive on wind-drifted slopes, especially at upper elevations.  A rippled snow surface, pillows, or dunes indicate the wind has been at work. Blowing snow will point in the direction of fresh slab formation. Cracking or collapsing indicates you have found an unstable slab, directing you to a lower-angle slope. 

    (3/13/2025)

    The crown of a skier-triggered soft slab avalanche. Although you are most likely to find sensitive slabs in wind-affected terrain, it is still possible to trigger an avalanche on sheltered slopes. 

    Photo: Kaleb Retz

  • Persistent Slabs

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

    It remains unlikely that you will trigger a large avalanche on weak layers buried 2 to 4 feet deep. The most recent (suspected) avalanche on buried weak layers occurred last weekend. Surface hoar, facets, and faceted crusts formed in January and are slowly strengthening. 

    Weak layers may be closer to the surface - and easier to trigger - on wind-affected slopes with variable snowpack depth. Likely trigger points include convex or rocky slopes. You may not notice signs of instability like cracking and collapsing before triggering an avalanche. Hard slabs can break much wider than expected and in surprising ways. Surface slides or cornice fall could trigger a larger avalanche on buried weak layers.

    Digging into the snow is the only way to identify if your slope contains this layer. Choosing lower-angle terrain not connected to steep slopes is the easiest way to avoid this problem.

    This large slab avalanche on Peak 7798' in the Flathead Range is estimated to have released sometime between 3/8-10. It is presumed to have failed on buried weak layers.  ESE aspect aspect. 7200'.

    Photo: Michael Reavis

Avalanche Discussion

We've seen some dynamic weather since the end of February: Thawing, rain, snowfall, sunshine, wind. It's all combined to produce a highly variable structure in the top 1 to 2 feet of the snowpack. Snowfall accumulations from the past week vary widely between 5500 to 6500 feet.  Southwest winds have redistributed this snowfall onto typical leeward (NW-N-NE-E-SE) slopes. The recent snowfall rests on a complex patchwork of thin crusts and faceted snow (maybe even surface hoar).  What's the takeaway?  Realize that the size and sensitivity of slabs can vary significantly within a given elevation band, drainage, or even across the same slope.  

Today's weather will only add to the variability and could do so quickly. Afternoon snow showers and gusty winds may cause localized areas of heavy snowfall and intense wind loading.  If the storm arrives earlier and angrier than forecasted, expect some upper elevation locations to reach CONSIDERABLE.  Default to low-angle terrain if you encounter red flags like blowing snow or cracking in the new snow. 

A spat of shallow slab avalanches continued yesterday near Whitefish Mountain Resort. A video of a rider-triggered avalanche on Hellroaring Peak serves as a reminder to carry avalanche safety gear, including a beacon, shovel, and probe, even when accessing the backcountry through ski area boundaries. Luckily, this slide was small in size, and the rider was not completely buried. This slope is within view of the ski hill and has a history of producing surprising avalanches.

Curious about recent developments in tele boots and bindings? 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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