Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
View on map

Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

The avalanche hazard is decreasing but remains complex.  You can still trigger large avalanches in wind-drifted snow or deeper down on buried weak layers. Recent avalanches, cracking in the surface snow, and collapsing direct you to lower-angle terrain free of overhead hazards. Yesterday (Thursday), a rider remotely triggered a large avalanche in the Whitefish Range.

Avalanche problems

  • Persistent Slabs

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

    Large (D2) avalanches ran naturally during Wednesday's storm.  These slides occurred as new and wind-drifted snow overloaded a weak layer of surface hoar or facets buried 1.5-2.5 feet deep.

    • These layers remain sensitive to the weight of a human and/or their machine and can be triggered remotely from attached low-angle terrain.  
    • Audible collapses indicate that you have found a buried weak layer and should signal you to move to less steep terrain.  
    • Slopes that face south and southwest also present a safer option, as weak layers appear less reactive on these aspects.

    (12/9/2024)

    Crown profile on a northeast aspect at 6500 feet. This avalanche failed on surface hoar. Similar avalanches occured during Wednesday's storm.  These layers are still adjusting to new and wind-drifted snow.

    Photo: Cameron Johnson

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2.5

    Powerful winds redistributed snowfall during Wednesday's storm.  Although the wind has subsided, it remains possible to trigger large avalanches in wind-drifted snow:

    • Recognize wind-drifted snow by its scalloped surface or dune-shaped features.
    • Look for these signs downwind from ridges, saddles, and other prominent terrain features.
    • Due to intense winds, drifts can be found further downslope than is typical. 
    • Slabs could be firm enough to support your weight but might break above you and wider than expected.
    • In areas favored by recent snowfall, it is possible to trigger slabs in sheltered areas.

    Manage this problem by choosing slopes with less than 8 inches of new or wind-drifted snow.

    (12/2/2024)

    Wind slabs form downwind of ridges, saddles and other prominent terrain features.  Today, you might find them well down slope due to the intensity of recent winds. 

    Photo: Flathead Avalanche Center

Avalanche Discussion

Wednesday's storm increased variability across the advisory area.  Some areas were favored by snow, others by wind.  Most areas saw rain up above 5000', and some saw freezing rain up above 7000'.  Avalanches failing in the new snow were widespread, and a few locations saw bigger slides on buried weak layers.  The danger is decreasing, but the variability remains and can make travel tricky. 

Expect some surprises if you haven't been out since last weekend.  You could find recent crusts or wind-stiffened surfaces on any aspect or elevation.  Crusts might be on the surface or buried deeply by wind-drifted snow.  The size of drifts could vary wildly.  They might range from soft to hard and could be found in unusual locations. Other areas could be stripped down to the ground.  

Our biggest surprise this week? Finding an intact and reactive facet layer in the Swan Range. We have relisted Persistent Slab for this zone. The layer was reportedly destroyed by rain in the Jewel Basin and Swan Lake areas; however, it appears preserved in the range's northern and eastern parts. This layer remains concerning in the Whitefish Range, Flathead Range and Glacier National Park.   A rider on Werner Peak in the Whitefish Range remotely triggered a large avalanche yesterday (Thursday).

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.  

Regions covered