Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

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

Prolonged sunshine and warming temperatures may develop wet snow avalanches in this week's fresh snow. Be aware of changing surface conditions on steep, sunlit slopes, especially this afternoon. You can still trigger a large avalanche involving buried weak layers on shady slopes. These are more likely to occur in locations without a supportable crust.  

Avalanche problems

  • Loose Wet

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

    Today’s increasing temperatures and mostly sunny skies may warm and moisten recent snowfall on solar aspects. Natural wet loose avalanches could develop during sustained periods of direct sun, particularly in steep, rocky terrain. It will be possible for a rider to trigger a slide on these slopes as they warm. Any triggered slides may travel surprisingly far on the underlying crust. Slides on shady aspects are unlikely, but monitor the relatively dry surface snow to see if it becomes moist. 

    Keep an eye on snow falling from tree branches or rollerballs developing in the recent snow. These indicate the snow is warming, and wet loose slides may follow. Plan your day to stay ahead of the sun, including your afternoon exit. Move to a shadier slope if you note signs of instability, such as sinking into a mushy, wet snow surface. 

    During last weekend’s heat wave, loose slides triggered large avalanches on buried weak layers. Although not expected today, loose surface slides could initiate a destructive hard slab avalanche, as described in our Persistent Slab problem.

    (2/28/2025) Steep, sun-baked rocky slopes are the most likely locations for wet loose slides today. 

    Photo: Chris Gotschalk

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–2.5

    January’s weak layers (sugary facets, surface hoar, or facets + crusts) rest beneath a 2-3 foot thick slab deposited in February. You can trigger a large avalanche where these weak layers are preserved and susceptible to the weight of a rider. The most likely locations are on steep shaded slopes that did not slide during the February Atmospheric River and last weekend’s heat wave. Solar aspects are generally capped with a stout, supportable crust that limits your ability to impact the weak layer. Although less likely, you could trigger slides on these slopes if the crust breaks down or is nonexistent. 

    The chance of triggering a slide increases in wind-affected terrain where the slab depth is variable and the weak layer is closer to the surface. Before triggering an avalanche, you may not experience noticeable signs of instability like snowpack cracking and collapsing.

    Persistent Slabs can break much wider than expected and in surprising ways. Surface slides or cornice fall could result in a large 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.

    (3/2/2025)

    Widely propagating avalanche off the ridge south of Mount Liebig. You are most likely to trigger a large avalanche on shaded alpine slopes where weak layers were not wiped out by recent avalanches or capped by a stout melt-freeze crust. Likely trigger points include convex roll-overs or slopes peppered with rocks. 

    Photo: Paul Fotter

Avalanche Discussion

A warming trend began Thursday and will continue through the weekend, developing wet snow avalanche problems. This thawing event should differ from last weekend's heat wave with slightly cooler daytime temperatures, more cloud cover on Saturday and Sunday, more wind to cool the surface, and below-freezing overnight temperatures.  We expect the 5-10 inches of snow that fell this week to sluff on steep, sunlit slopes. In many locations, this snow rests on a stout crust, which the surface slides may not break through, limiting entrainment and subsequent size of the slides. A solid overnight refreeze and a thick surface crust may limit wet slab development.

Our uncertainty on Saturday and Sunday is whether partly cloudy conditions will develop a greenhouse effect, allowing for the warming of the surface snow on shaded aspects.  Last weekend's heat wave generally did not affect the surface on the north side of the compass. If slides develop in this terrain, they could entrain substantial amounts of dry snow. Debris moving downhill could trigger a much larger avalanche on buried weak layers.  

Glide avalanche concerns return for the next few days as meltwater develops at the surface. Glide cracks are found in all aspects at mid and upper elevations but are concentrated in sunny, mid-elevations. The Swan Front is a hotbed of activity with at least 28 visible from the valley floor. Thanks to our dedicated Swan Range observer for this information (Observation). Continue to mitigate this problem by avoiding slopes with glide cracks.

Warming temperatures and sunshine could weaken cornices and cause them to fail, possibly triggering a much larger slab avalanche on the slopes below. Limit your time spent below these features, and while traveling ridgelines, keep further back from their edge than you think is necessary.  

We are saddened to report that the recent heli-skiing incident in Alaska took the life of a member of the Flathead backcountry community. Charlie Eppard was a loving father, devoted husband, and long-time supporter of FAC and FOFAC. You can support his wife, Brittany, and their young daughter at this Go Fund Me account. An article in the Daily Interlake detailing this tragedy can be found here. 

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