Avalanche forecast

Flathead Range & Glacier NP

Flathead Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Steer around drifted snow and overhanging cornices along ridgelines. Choose terrain less than 35 degrees in steepness and avoid traveling above terrain traps like cliffs and gullies. Whumpfing collapses are a sign that it is still possible to trigger an avalanche on weak layers buried near the ground.  Loose snow can sluff easily on firm surfaces.

Avalanche problems

  • Wind Slabs

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

    Cooler weather and precipitation have left plenty of snow available for transport. Fortunately, winds have remained surprisingly light the past couple of days. Southwest winds are increasing and will drift snow onto leeward aspects throughout the day. Expect to encounter thin slabs on the downwind side of ridgelines and saddles or the sidewalls of cross-loaded gullies. You may find isolated slabs on mid-elevation slopes favored by southwest flow, such as John F. Stevens Canyon. You can identify this surface problem by a denser snow surface that you may find yourself riding on top of. Choose sheltered terrain for a safer experience and more enjoyable riding. 

    (12/30/2022)

    Wind loading in JFS canyon. 

    Photo: Adam Clark

  • Persistent Slabs

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

    We continue to receive mixed messages from weak snow buried near the ground. Overall, evidence supports that it is becoming increasingly difficult to trigger a slide on the November facet layer.  However, even scattered signs of instability  - like whumpfing collapses or shooting cracks - are a reason to remain skeptical. You are most likely to get surprised on slopes steeper than 35 degrees, convex rollovers, or areas with shallow snow due to sun or wind scouring.  Your outcome will be the most severe above terrain traps like cliffs, gullies, and exposed rocks and trees.

  • Loose Dry

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

    Recent snowfall is unconsolidated and caps a crust in many locations. Skiers triggered sluffs large enough to knock a person over or pin them to a tree Friday. Slides may run far where the crust is closer to the surface. This problem is generally confined to steep slopes around 38 degrees or steeper with eight inches or more loose snow. Choose lines free of terrain traps where snow can pile up deep. Opt for slopes clear of surface obstacles you or your machine could encounter if you lose footing. Manage your sluff if you are planning to step out into steep terrain.

Avalanche Discussion

Well, how did everyone  do in 2022?  Things got a little weird for a minute there. Queue up the music and let’s roll that year-in-review montage..

We enjoyed some exceptional early season coverage, and speculated about the role the November facets would play this season.  Then, we felt an impending sense of doom as “rolling thunder” rang out on this weak layer.  Finally, we endured a frigid visit from the North Pole and even fit in a quick rain-on-snow event.  We packed a whole winter into just November and December!  Now we’ve got fast and dry riding conditions to close-out the year.  We’re on the up and up.

Call it what you will – “The Santa Soaker”, “The Holiday Hosing”, or simply “Crust-mas” – last week’s rain left us with a crust of variable thickness up to just above 7000 feet.  This crust combined with waning observations of collapsing had me optimistic that we could leave our persistent slab problem behind us. However, Cam’s report  of whumpfing from the Northern Swan and Blase’s saw tests in the Southern Whitefish suggest that this bad habit will be sticking with us into the new year.  

What are some good habits we can set our sights on for 2023?  Avoiding travel above terrain traps like cliffs, gullies or exposed rocks and trees.  Also, watch for cornices and give them a wide berth as you navigate on or under ridge lines.  They appear to have gained some weight over the holidays and are looking a little tipsy.

Training: Make 2023 the year of companion rescue skills. Transceiver parks are open at Whitefish Mountain Resort, one at the summit and one adjacent to Grey Wolf. Both are accessible to snowmachines. You can get more details about training and education opportunities events on our events calendar.

Regions covered