Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

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

Large human-triggered avalanches occurred within the last 24 hours. Stick to lower angled slopes on shaded aspects above 6500 feet. New snow and southwest winds will form thin slabs of drifted snow. Windward aspects are safer options for riding. 

Avalanche problems

  • Persistent Slabs

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

    Recent avalanches are a glaring red flag. In the past three days, there have been two accidents and two near-misses, all in the Flathead Range. Additionally, south of the advisory area near Seeley Lake, a rider triggered a large avalanche failing on this same layer. We’ve received no reports of triggered avalanches in the Whitefish Range, though we aren’t ruling the problem out in that zone.

    Signs of whumpfing, collapsing, and shooting cracks are all signs of instability but are not common with this weak layer. Avalanches are breaking 1 to 2 feet deep, on weak facets a few inches above a hard crust. The best tactic is avoidance. Slopes that face north and east are proving most sensitive. Avalanches have failed on slopes with angles in the low 30-degree range.

    (2/17/2024)

    Slabs are failing 1 to 2 feet thick with no warning. This avalanche, like all of the other triggered avalanches, failed on upper elevation slopes that face north and east. 

    Photo: Zach Miller

  • Wind Slabs

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

    Winds will drift new snow into fresh slabs sensitive to the weight of the rider. Slabs of drifted snow should be small unless snow accumulations exceed forecast totals. Pay attention to the amount of freshly fallen snow and signs of instability. Cracking around your boards or machine is a sign of an unstable slab. 

    Slabs of wind-drifted snow are adding weight to a poor snowpack structure. A small avalanche may easily step down to a weak layer buried 1 to 2 feet below the surface. If this occurs, slabs will break wider than you may expect and be difficult to escape.

    Blowing snow like this indicates that the wind is drifting snow and forming wind slabs beneath the ridge line. 

    Photo: Rob Millspaugh

Avalanche Discussion

Today, southwest winds will drift the couple of inches of new snow that falls. Expect thin and small slabs to form on leeward-facing aspects. A sun crust will limit the amount of snow available for transport, so drifting should be fairly minimal. The aspects being drifted are the same aspects where people have triggered large avalanches failing on a persistent weak layer 1 to 2 feet below the surface.

Reported human-triggered avalanches are confined to shaded aspects above 6500 feet in the Flathead Range. I suggest dialing slope angles back wherever you feel a hard crust buried more than a foot below the surface. Signs of instability and snowpack tests are not providing negative feedback, which may dupe a person into thinking the slope is stable. Here is an example.

Yesterday, Blase and I visited the crown of a recent human-triggered avalanche. This avalanche failed on facets a few inches above the early February crust. During our descent, we unintentionally triggered a neighboring slope. The start of this slope had a planar/concave shape with slope angles in the low 30s. The slope was relatively short and sparsely vegetated. Prior to the slide, we observed no signs of unstable snow on neighboring slopes and no alarming results in tests. The one red flag was the nearby avalanche.  The first rider on the slope triggered the slide just below the ridgeline and could not escape the moving debris. The rider was caught, carried, and lost some equipment. 

Experienced teams and veteran forecasters are getting surprised. This is not a problem to try to outsmart. Keep it simple. 

Upcoming event: Flathead Avalanche Friends Fest, February 21-24. We have four days of events on tap for you: Beacons & Brews, Name That Tune/Name That Avalanche, Workshop Night with State of the Snowpack and USGS, Hot Dog Days, and the Ultimate Après with Backcountry Partner Speed Dating and the Big A$$ Raffle. More info at flatheadavalanche.org/event/friendsfest

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