Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Natural and human-triggered avalanches occurred Wednesday. The storm has ended, but the hazard remains elevated where fresh, dense slabs rest on lower-density snow. As you climb in elevation, slab size will increase and be particularly dangerous in areas of wind-drifted snow. Recent avalanches, cracking in the surface snow, and collapsing direct you to lower-angle terrain free of overhead hazards. 

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3

    The recent storm deposited a dense slab on top of lower-density snow, creating an unstable and reactive avalanche problem. Natural and remotely triggered slides failed in the new snow (image to the right or above). The storm snow now rests 1-2+ feet above a layer of previously buried surface hoar or facets on shaded slopes. The potential remains for a rider to trigger a slide on this deeper buried weak layer, or a surface slide could step down to that layer, resulting in a much larger avalanche. 

    Slabs will increase in size and thickness with elevation and could be 2-3 feet thick on upper elevation wind-loaded slopes. Today would be a good day to limit your exposure to steep slopes with 8 or more inches of new snow. You can remotely trigger a slide from flat terrain above, below, or to the sides of a steep slope. Cracking in the snow surface and collapsing whumpfs indicate you have located an unstable slab. 

     

    (12/18/2024)

    Wednesday's dense snowfall fell on low-density surface snow, forming an unstable slab. This soft slab failed on a steep slope east of the WMR ski area boundary.

    Photo: Flathead Avalanche Center

Avalanche Discussion

Wednesday’s heavy snow fell on a widespread layer of lighter, drier snow, resulting in an unstable upside-down surface. Moderate to strong winds transported the new snow into thick, dense slabs on leeward slopes. Observations are sparse, but we assume a natural avalanche cycle coincided with periods of intense precipitation. 

The warm, wet weather affected all zones and elevations but favored the Whitefish Range with storm totals of 1.3 inches of water at WMR, 1.5 inches at Stahl Peak, and central Glacier Park with 1.6 inches. The snow line climbed throughout the event, with mid-elevation stations reaching near or above freezing temperatures. Rain fell to or above 5500 feet on the Swan Front (image).

Cam was in the southern Whitefish Range, where he noted six soft slab avalanches failing on a density change 6-10 inches deep. He remotely triggered one slide and observed widespread cracking and several collapses. 

In the Swan, Rob observed intense wind loading from strong winds and gale-force gusts. Snowpit tests revealed hair trigger propagation beneath a recent crust 20cm down. 

Although the natural cycle has ended, it remains likely that a rider could trigger an avalanche in the fresh slab. We recommend giving the new and wind-blown snow additional time to strengthen before committing to steep terrain. 

Downloaded the app yet? You can now access our region's forecasts, observations, and weather data directly from the Avy App (IOS; Android). Many features are accessible offline, so you can doublecheck danger ratings and travel advice on the drive or in the backcountry. And submit an obs while driving home. 

Are you looking for avalanche education opportunities? Check out our calendar for upcoming events. A Partner Rescue Clinic for motorized Riders on January 4 would be a great way to start the new year.  

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