Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Dangerous avalanche conditions will continue. Think twice before traveling on exposed, leeward slopes with drifted snow. Sensitive wind slabs that formed over the last 24 hours will be larger and more dangerous at higher elevations. New snow may mask their characteristic rippled texture and pillowy shape.

Avalanche problems

  • Wind Slabs

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

    Slabs of drifted snow formed over the last 3 days. Poor visibility prevented clear views of upper elevation terrain. I suspect that human triggered wind slab avalanches 6 to 20 inches deep became more sensitive Thursday afternoon. Some of the most intense blowing snow occurred overnight. Avoid venturing onto open, wind-affected slopes steeper than 35 degrees. The small avalanches you trigger on test slopes at middle elevations are just a taste of the slabs waiting in big terrain. If you see recent natural avalanches, or experience shooting cracks or collapses, dial it back and look for sheltered terrain. New snow that accumulates throughout the day can make recent slabs harder to identify.

    (12/23/2021)

    An FAC Forecaster team triggered this small, soft slab of drifted snow on a mid-elevation leeward slope in the southern corner of Glacier National Park.

    Photo: Nelson

Avalanche Discussion

It’s Christmas eve, and NORAD (the military missile defense command) will be tracking Santa’s progress overnight. Here in Northwest Montana, we’re tracking an overrunning storm event that will bring heavy snowfall to the region by this evening. We hope Rudolph is well rested; he might need the high beams. 

New snow Friday and Saturday will cover recently-formed wind slabs.

Three days of increasing wind speeds and blowing snow have drifted recent snow into slabs 1 to 3 feet thick onto leeward slopes. Foreasters and WMR Ski patrol reported natural and artificially triggered soft slab avalanches near and above treeline Wednesday and Thursday. Most slides have failed at interfaces of low-density snow between layers. In the southern and eastern parts of the forecast area, surface hoar and near surface facets may lie 1 to 2 feet below the surface.

The middle of the snowpack is generally right-side up and strong. Small, rounding facets around crusts sit near the ground 3 to 6 feet below the surface. We have only had a handful of snowpack tests fail on that layer. So, most of our avalanche problems focus on new and recent snow and wind.

If you haven't noticed yet, we have a new Conditons Blog tab attached to this forecast. It's updated every Friday, which means we're all treated to lead forecaster Mark Dundas's summary of current condions. Think of it as an early present.

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