Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

Enjoy generally safe avalanche conditions and quality riding. Watch out for small slabs of wind-drifted snow at upper elevations. Triggering one of these isolated slabs may have consequences if the debris pushes you over cliffs or into rocks and stumps. Expose only one rider at a time if you choose to ride in steep terrain. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1–1.5

    Southwest winds averaged speeds capable of transporting snow over the past 24-48 hours. Slabs of drifted snow will be relatively thin and  mostly harmless in size. 

    Steer around small pockets of wind-drifted snow. Slabs often have a dune shape to them or a pillowy look. Wind slabs typically form downwind of ridges and saddles and can crossroad gullies further downslope. You can reduce the chance of triggering a small slide by choosing terrain sheltered from southwest winds. 

    (12/2/2024)

    We triggered two small wind slab avalanches on steep rollovers mid-slope. These failed between 6000 and 6500 feet. 

    Photo: Flathead Avalanche Center

Avalanche Discussion

Welcome to the first avalanche forecast of the 2024-2025 season. We are excited to be here and wish everyone a safe and enjoyable season. 

An atmospheric river in mid-November kicked off our season with an above-average snowpack, good stability, and better access than usual. Observations throughout the forecast area generally describe low avalanche danger with isolated areas of unstable snow. Here are links to observations that help paint the picture of current conditions (Whitefish Range, Flathead Range, central Glacier National Park, Apgars). 

Wind speeds in the mid-teens and low twenties transported snow into fresh slabs. Monday, we found small pockets of wind-drifted snow in isolated areas. These fresh and small slabs of drifted snow failed on near-surface facets, so expect them to remain sensitive to human triggers longer than usual. Although they are harmless in size, they may be consequential in extreme terrain. Be wary of riding on wind-loaded slopes above cliff bands or slopes that terminate in steep gullies. Although we do have good coverage for this time of year, there are still many surface obstacles to get slammed into that would increase your chances of trauma if caught. 

Strong temperature inversions and sunshine initiated a round of small rollerballs and loose snow slides yesterday. If you head out today, expect to find a sun crust on solar aspects. This sun crust will reduce, but not eliminate, the chance of loose snow slides today. Areas most likely to slide will be steep, rocky slopes getting direct sunlight. The December sun does not pack a lot of heat due to its low angle in the sky, so expect this to be a short-lived problem.

You can find persistent weak layers buried in the snowpack, but no signs indicate they are a problem yet. The one closest to the surface is facets around the crust that formed during the atmospheric river event. This crust is buried about 40 cm (16 inches) below the surface. This crust is easy to get to by hand pits or a little digging. You can identify if there are facets around the crust by using your finger to test the hardness. You've found facets if you find a thin layer of soft, sugary snow sandwiched between the crust and harder snow. This will be helpful information for us moving into the weekend when we expect more snow.

The other weak layer we are closely monitoring is the surface. Surface hoar and near-surface facets currently blanket the landscape on shaded aspects. The current weather pattern is driving strong temperature gradients at the surface, creating weak snow. If this weak layer gets buried intact, it will drive avalanche activity once snowfall returns. 

Registration is open for this season's avalanche courses; click the links below each relevant course.

We have an Avalanche Awareness class this Wednesday, December 4, at Andy's Craft House in Big Fork. Pre-registration is not required.

Regions covered