Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

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

The snowpack continues strengthening following this past week's bountiful precipitation. You may encounter thin slabs of recent snow reactive to the weight of a rider or snowmachine. If so, change your aspect or elevation to find the numerous slopes holding soft snow. If we receive sustained sunshine, expect small wet loose activity to develop. 

Avalanche problems

  • Storm Slabs

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

    Mid elevation weather stations picked up 6-8 inches of snow Friday. Light winds and cool temperatures have kept this snow generally loose and dry. As this surface snow settles or gets blown around by the wind, you may find thin slabs resting on a widespread rain crust or firmer old snow. As you transition from areas holding loose snow to those with a more dense surface, cracking will indicate that you have found a slab. Utilize hand pits or test slopes to see how well this snow bonds to the underlying surface. If you don't like what you've found, look elsewhere because many slopes still hold loose snow.

    (3/5/2022)

    Thick crowns produced very large slides throughout the Flathead Range. 

    Photo: Mark Dundas

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Saturday morning's sunshine warmed the cool loose surface snow and started producing rollerballs and small wet loose slides on steep southerly slopes. Clouds rolled in around noon and shut down the solar input and wet loose activity. On sunny aspects, there remains loose snow available for wetting, warming, and producing small wet loose slides. Today's forecast is for mostly cloudy conditions until later afternoon. If the forecast holds true, there may only be a wet loose concern on southwest or west aspects late in the day. If the clouds break earlier, expect loose activity on other slopes. Rollerballs and snow falling from trees is a precursor to wet slides.

    (3/5/2022)

    Debris piles reached historic runouts in some location in the Flathead Range. This debris pile was roughly 20 feet deep. 

    Photo: Mark Dundas

Avalanche Discussion

Due to the nastiness of this past week's weather, FAC has received few observations. With improving conditions, observations are trickling in. Folks generally find a surface crust that is mainly supportable to skis but not to foot. Boot penetration remains crotch deep, with moist to wet snow below the surface. Fortunately, conditions cooled late Thursday and Friday, and there was enough residual moisture to deposit 4 - 8 inches of snow on top of the rain layer at mid and upper elevations. 

FAC staff is interested in gathering avalanche data following the 5 - 6 inches of water that fell over our area. In the Middle Fork, it appears that there was a widespread dry slab cycle early in the storm, followed by a wet loose cycle in those same paths later in the storm. The dry slabs ran far and reached the valley floor. The wet debris reached the valley floor in about half the paths. Saturday, I was in Skiumah and noted wet debris piles up to 20 feet deep which ran to their historic runout. We also spotted around 40 crowns at all elevations. I'm sure there were probably more crowns, but we got tired of looking.

We have removed Persistent Slab from the Avalanche Problem list. This problem has come and gone from our forecast several times this season. This past week's forecasted Atmospheric River weather event was a significant loading event that concerned FAC staff. With the event over and the upper snowpack strengthening, we think these buried weak layers are dormant.

There are still a few educational opportunities before season end:

Motorized Introduction to Avalanches 03/17/2022 to 03/19/2022

Community Fireside Chat - Near misses and close calls; what we can learn Tuesday, March 22nd - 6:30 PM (virtual)

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