Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

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

As you ascend in elevation, look for recently-formed wind slabs along and near ridgelines. You've spotted one if you encounter scalloped or hollow-sounding snow. Avoid convex, unsupported northerly slopes at upper elevations, where there's a lingering hazard of triggering hard slabs on deeply buried weak layers.

Avalanche problems

  • Wind Slabs

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

    Over the last 48 hours, a shift in wind direction from north-northeast to south-southwest has left wind-blownsnow on all aspects of the compass. The drifts are most pronounced beneath ridgelines and along mid elevation ribs and gullies. 

    Look for signs of wind effect such as blowing snow, textured surfaces, and hollow-sounding areas. Shooting cracks are signs of instability. Although shallow, these slabs are likely resting  on a widespread melt-freeze crust or weak, faceted snow, which could increase their sensitivity. 

    The consequences of one of these slabs may be minimal in simple terrain. However,the potential for injury increases significantly if you are knocked off your feet above a terrain trap .

    (3/22/2024)

    This image shows multiple drifts and cornices formed by shifting winds. The blue arrows point in the wind's direction to create each feature.

    Photo: Mark Dundas

  • Persistent Slabs

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

    The February 3rd crust/facet combo is buried 3-5 feet below the snow surface and faceted crystals above the crust are slowly rounding. The lack of recent avalanche activity across the forecast area has allowed us to lower the likelihood of triggering one of these avalanches. However, the hazard of triggering large to very large hard slabs lingers on upper elevation, northerly aspects. 

    The slopes where you a person is most likely to collapse this weak layer have varaible snow cover with thin spots. New and recent dry snow may camouflage these slopes. Multiple people could ride a slope before you trigger a slide. You can find safer travel on slopes less than about 30 degrees.

    (3/17/2024)

    This is a hard slab avalanche on Nyack Mountain that failed on a northeast aspect at upper elevations on March 16. This slide likely failed on a layer of facets above the early February crust.

    Photo: Mark Dundas

Avalanche Discussion

I’ve heard and read from those of us who won’t give up on winter saying, “Best days of the year!” and “Surprisingly, some of the best quality snow I’ve skied…”. It’s certainly out there if you are willing to put in the time to get to mid and upper elevations around the forecast area. Yesterday (Monday), I traveled on various aspects in the southern Whitefish Range and found up to 30 cm of settled powder on top of a 4-6 cm crust formed between March 14-18 (WMR sidecountry, Southern WF Range). Others in the area found reactive wind slabs on small test slopes and shooting cracks on mid elevations on southerly aspects (WMR sidecountry). You can expect the avalanche hazard to increase as you gain elevation into terrain more exposed to the wind.

Light to moderate northerly winds over the weekend transported up to a foot of recent snow onto atypical aspects (southeast-south-southwest) throughout the forecast area at mid and upper elevations. Today, expect cooler than average temperatures to continue with intermittent snow showers favoring the Swan Range. In the event snow totals exceed 5-8 inches, expect dry loose avalanches to break under your boards or machine on slopes over 35 degrees.

Due to the ever-changing nature of late winter/early spring weather in the mountains be on the lookout for warming temps that may increase the chance of wet-loose avalanches on low and mid elevation slopes. If you notice rollerballs or dry surface snow changing to moist, head to more shaded aspects or lower-angle terrain.

Join us Thursday for our spring workshop night, with a State of the Snowpack & the Scoop on Spring Touring presented by Lead Forecaster Mark Dundas. You'll leave with a better understanding of current conditions, spring avalanche problems, and how to plan a successful day out this time of year.

March 28 from 6 to 7:30 pm at Scout's Grille, 27 Scout Lane, Columbia Falls (Hwy 40). Ice cream provided by Sweat Peaks. Free to attend, no sign-up required.

Regions covered