Lawinenlagebericht

Flathead Range & Glacier NP

Flathead Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 6 months ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Triggering a large avalanche on a buried weak layer remains our primary concern. Sunny slopes with a supportable crust offer the safest option for navigating this avalanche problem. Track storm totals as the day progresses and adjust your terrain selection as necessary. 

3 to 6 inches of snow may fall today. Plan for a loose dry avalanche problem IF we see the higher end of those snow totals.

Lawinenprobleme

  • Loose Dry

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    A storm system may impact the Swan and Flathead Ranges, dropping 3 to 6 inches of new snow with light winds. If we see the higher end of precipitation totals, expect a loose dry avalanche problem. These will be more common on solar aspects with a hard, supportable crust. Although loose dry avalanches are easy to manage and relatively predictable, avoid getting knocked over in consequential terrain. Descend in a way that allows your sluff to run next to you, not over you.

    (1/27/2025)

    A small skier triggered loose dry avalanche. Small slides like this may become easy to trigger on slopes where new snow is landed on a surface crust.

    Photo: Cam Johnson

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–2.5

    A well-preserved buried weak layer exists in the upper snowpack. It is buried within the top foot in areas sheltered from the wind and about 2 feet deep on wind-loaded slopes. This weak layer is responsible for both human-triggered and natural slab avalanches last week.

    Be especially wary of slopes that are typically shaded by the sun, where no crust exists at or just below the surface. These slopes are the most likely places to trigger a large avalanche. You can reduce your chances of triggering a large avalanche by riding on slopes with a supportable crust or by choosing slopes with lower slope angles.

    (2/3/2026)

    Riders were ascending a northerly-facing slope when they triggered this thin, soft slab. This avalanche likely failed on a buried weak layer.

    Photo: Flathead Avalanche Center

Avalanche Discussion

A cold front today will impact the southern half of the advisory area. Forecast models tend to agree on .2 to .4 inches of precipitation, which will hopefully turn into 3 to 6 inches of snow. The northern half of the forecast area will likely see a trace to an inch of snow. Wind speeds dropped to the single digits overnight, and that pattern continues today.

If you head out looking for soft snow, be wary of steep slopes that face northwest to northeast to east. A weak layer of surface hoar or facets near a crust about a foot below the surface was responsible for natural and remotely triggered avalanches last week. There is a higher-than-usual level of uncertainty about how this weak layer will respond to new snow. Typically, I wouldn’t think much about less than a half-inch of water, but not all avalanche problems are the same. This particular weak layer has proven to be very sensitive to minimal loading in the past. I can only anticipate it being problematic with each loading event. If you are seeing snow beginning to pile up today, your safest bet is to give a wider margin between you and steep slopes that are typically shaded from the sun.

The near-record-setting heat wave has subsided. Temperatures began dropping yesterday (Sunday), and freezing levels will continue to drop today. Cooling temperatures refroze the snow surface on sun-affected slopes. As a result, we have trimmed the distribution of the Persistent Slab avalanche problem.

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