Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
View on map

Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

New snow and strong winds will increase the avalanche danger throughout the day. Slabs of drifted snow may become reactive to the weight of a rider. Stick to terrain sheltered from the wind if you see blowing snow and more than 6 inches of new snow stack up. Be wary of thicker slabs of drifted snow on leeward and crossloaded slopes above roughly 6500 feet that formed this past weekend. Although you're less likely to trigger these slabs, they would be large enough to bury and injure a human.

Avalanche problems

  • Wind Slabs

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

    New snow accumulations will range from 3 to 10 inches across the forecast area, with an additional 2 to 9 inches overnight. Winds will continue to climb with speeds averaging 15 mph out of the southwest, transporting new snow onto leeward aspects. I expect freshly formed wind slabs to be mostly small and manageable today, although some may grow large enough to bury and injure a human overnight. The exception is if you find yourself in an area that receives more than 6 inches of new snow. If you only see a few inches of new snow accumulate today, and conditions are pointing you towards stepping out into steeper terrain, hedge your bets on slopes that are sheltered from the wind.

Avalanche Discussion

Thanks to all the recent observations, we have a good understanding of surface conditions going into this quick-hitting storm. In all three forecast zones, we received reports of surface hoar on sheltered aspects at middle and upper elevations, sun crusts forming on solar aspects below roughly 6500’, and a rain crust that stretches up to roughly 4600’. So, how do we use this information and how might it change your travel plans?

Winds will transport new snow onto aspects likely containing surface hoar. This finicky weak layer is notorious for producing touchy avalanche conditions during loading events and can persist for a long time. Today, track snow totals and plan to stick to slopes less than 35 degrees if you see more than 6 inches of new snowfall. Slabs will be more dangerous on wind-loaded terrain features.

Expect new snow to sluff easily on solar aspects containing a sun crust, and at low elevations where a rain crust formed. Sluffs will likely be harmless in size, but worth noting if you plan to step out into more exposed, windward terrain that faces south today. Manage your sluff with defensive riding strategies.

An older generation of wind slabs remain a concern of ours. Although trending towards unreactive, hedge your bets by avoiding large, upper elevation start zones that face north through east. These will be the same aspects that will receive additional loading today. There is plenty of good riding to be had on slopes sheltered from the wind.

You will notice we removed persistent slab from the problem list. We feel confident in doing so after no observed naturals containing old snow occurred with the last storm. However, large and very large avalanches occurred on faceted crusts near the ground just over the border in Canada. This may be more of a concern if your travels take you to the far northern part of the Whiteish Range.

Regions covered