Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

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

Weekend wind and snow built widespread drifts and cornices reactive to the weight of a rider. You could still trigger an avalanche on steep, wind-loaded slopes, especially in areas favored by recent snow.  Low-angle terrain sheltered from the wind will offer the safest and best quality snow. If the sun makes a sustained appearance, anticipate wet snow sluffs to develop on steep slopes facing the sun. 

Avalanche problems

  • Wind Slabs

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

    Sunday's impressive wind speeds transported the weekend storm snow and built sensitive slabs and cornices. These features will be thicker, more widespread, and most dangerous in locations with the most snow and wind. You will find these downwind of ridgelines and saddles, in mid-slope cross-loaded gullies, and behind prominent terrain features like rock outcroppings or tree islands. 

    Avalanches at the surface could entrain the bountiful snow from the past week, producing a much larger slide. Any slide could trigger a large avalanche on buried weak layers, as described in our Persistent Slab problem. 

    Today's winds will thicken existing features in favored locations. Blowing snow will point in the direction of slab formation. An etched surface, dunes, and pillow-like features indicate the wind has been at work. Cracks shooting out from your boards or machine confirm you have found a sensitive slab.

    While traveling along ridgelines, give fresh cornices a wide berth as they tend to break further back than expected. Slopes sheltered from the wind offer a generally safer experience and higher-quality snow. However, you could trigger a slide in these locations if you encounter stiffer snow.

  • Persistent Slabs

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

    January's weak layers (facets, facets + crusts, surface hoar) are getting buried progressively deeper by March snowfall. Their distribution is isolated, and due to their depth, triggering a large avalanche is unlikely but not impossible. This weekend's moderate to strong SW-W winds stressed these layers by transporting snow onto slopes harboring weak snow. We are unsure if these conditions produced natural avalanches over the past few days due to poor visibility and a lack of observations. 

    You could trigger one of these beasts where the weak layer is closer to the surface, such as in wind-affected terrain with variable slab depth. The edge of a slab generally thins and is an ideal location for triggering. Locations with rocks or small trees and brush sticking out of the slope are likely spots. Before initiating an avalanche, you may not experience noticeable signs of instability like snowpack cracking and collapsing.

    Today's surface slides or cornice fall could trigger a Persistent Slab avalanche.

    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 mitigate this problem.

     

    (3/10/2025)

    Recent avalanche activity in the Flathead Range/Marion Lake region. This rocky slope is an example of where a hard slab avalanche can be most likely triggered due to a variable slab depth. 

    Photo: Michael Reavis

Avalanche Discussion

The weekend storm was productive, with over 1 inch of SWE (Snow Water Equivalent) recorded at Stahl Peak, Stryker Ridge, WMR, and Flattop. Southwest-to-west wind accompanied the snowfall and ramped up on Sunday with gale-force gusts driving the avalanche danger.

On Sunday, riders deliberately broke chunks of cornice that triggered wind slab avalanches on the slopes below in a notoriously windy location in southern Glacier Park (Observation). The WMR ski patrol triggered slabs with explosives and ski cuts in wind-affected ridgeline locations but found mostly cohesionless snow in most other locations. Blase and Lydia visited the Flathead Range, noting multiple natural and triggered slides in wind-affected terrain. Active wind transport occurred throughout their tour (Observation).

With reports that the storm snow is generally cohesionless in wind-protected locations, we have transitioned to a wind slab problem.

Brief periods of the intense March sun may occur today. If so, expect the weekend storm snow to moisten on slopes directly facing the sun. Rollerballs, snow peeling off rock faces, and falling from tree branches will be the first signs that the snow is warming up, and loose wet avalanches may follow.

We received a great photo of an avalanche pouring off of Mt Brown in Glacier Park from Thursday. You can see the image here or below in our media gallery.

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. 

Regions covered