Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
1 · Low
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Highlights

Snowfall finally arrived and is combining with impressive winds to create dangerous avalanche conditions. Expect to encounter fresh slabs of new and drifted snow reactive to the weight of a person or machine. This dense, thick snow is a clue to seek out lower-angled terrain or wind-sheltered slopes for a safer, more enjoyable experience

Avalanche problems

  • Storm Slabs

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

    Snowfall and air temperatures increased overnight, resulting in an upside-down snow surface which will exacerbate our storm slab problem. Wind speeds have been strong enough to drift snow for the past 48 hours and will continue today. Expect to encounter dangerous slabs of new and drifted snow above 5000 feet. Slabs will be the thickest downwind of ridgelines and saddles and identified by a distinctive dense, stiff feel. Cracking around you or shooting away from you is direct feedback to choose lower-angle terrain with slope angles less than roughly 30 degrees, or to seek out soft snow on slopes sheltered from the wind.

Avalanche Discussion

Snowfall associated with the current storm arrived later than forecast and generally less than expected, but enough to keep the danger elevated. Temperatures have warmed throughout the storm resulting in an upside-down snow surface. Winds have been the big driver in slab formation, with impressive wind speeds recorded at ridgeline weather stations, including a one-hour average wind speed of 60 mph and 6 hours of gusts above 80 mph at the Mt Aeneas wind sensor. On Saturday, parties in the Middle Fork and Apgars reported windy, stormy conditions throughout the day.

The winner of the snowfall derby was the Flattop SNOTEL in central Glacier Park, with 19 inches of snow and 2.3 inches of water. The Middle Fork corridor and Stevens Canyon picked up 8 to 10 inches with slightly less in the Whitefish Range. The usually reliable Swan Range recorded just a few inches this morning, where we replaced the Storm Slab problem with Wind Slab.

Pro Tip: Several weeks ago, a windstorm was responsible for bringing down numerous trees in Glacier Park and the Flathead Range. Traveling on the Sperry, Snyder Lake, Mt Brown trails in Glacier, and the Marion Lake trail is arduous due to the blowdown. We expect to find similar conditions on other trails when the coverage allows access.

We’re saddened to report an avalanche fatality Saturday in the Crystal Mountain area in Washington. This area had experienced hurricane-force, 100 mph, winds recently. You can find further details here.

Regions covered