Lawinenlagebericht

Whitefish Range

Flathead Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
2 · Mässig
Waldgrenze
1 · Gering
Unterhalb
1 · Gering
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Kernpunkte

There's plenty of great riding out there, on most aspects and elevations. In steeper terrain, you can still trigger avalanches that break 1.5 to 3 feet deep on weak layers buried before Christmas. This hazard is more widespread and will involve larger avalanches at upper elevations. 

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–3

    The hazard of triggering slabs that release on old, weak snow lingers. Triggered slabs can break 18 to 36 inches deep on a variety of persistent weak layers. On sunny slopes, the primary concern is facets above a melt-freeze crust. On shaded slopes, it's surface hoar buried in early December, or facets buried around Dec. 18th. 

    Sticking to slopes that aren't steep enough to slide is the simplest way to reduce your exposure to this hazard. Variability in snowpack structure makes steeper terrain a riskier proposition.  Before committing to steep slopes, evaluate the possibility and consequences of a slide. Steep, convex slopes and slopes scoured and drifted will have more potential trigger points. Slopes that end in rocks, trees, or gullies are more likely to result in trauma or deep burial to anyone caught. Whumpfing collapses are a clear sign that the structure for triggering slabs exists.

    (12/30/2024)

    A rider triggered avalanche that failed on facets buried in mid-December. 

    Photo: Cam Johnson

Avalanche Discussion

Rare conditions. But before any gushing about the riding, it's critical to note that you can still trigger dangerous avalanches. The storm snow may be more sensitive to the weight of a snowmachine or rider today, as it consolidates into soft slabs. Or gets stiffened by winds and drifted into slabs. Slope-specific evaluation of conditions can help you enjoy the new snow and the rest of the new year.

Most of Tuesday's observations highlighted deep, cohesionless powder. A few also noted that the snow seemed to be settling into slabs as the day progressed, and you can see that at weather stations, which recorded 2 to 5 inch drops in snow height. Slabs involving new snow can be surprisingly soft, so look for the subtle signs that indicate the new snow is consolidating and can act like a slab - cracking and test slopes or hand pits that release in chunks rather than loose powder. While loose dry avalanches become less likely as the snow settles, they remain a hazard in very steep, confined terrain.

Lastly, we've only had one recent report of a triggered slide that broke on old snow. This involved facets over a melt-freeze crust on a southerly aspect in the southern Whitefish Range. A similar sturcture has been noted in John F. Stevens Canyon. The surface hoar buried on Dec. 7th remains a concern as well. I'd be leery of any steep terrain where digging revealed a distinct grey stripe beneath the recent snow.

Ok, the gushing. Remarkable coverage for this time of year. The November AR and recent storms have laid down even some old-growth alder. And the snowpack is generally right-side up, with few reactive weak layers. And the riding... bottomless, low-density snow that's unaffected by wind or sun. Happy New Year, indeed. 

Downloaded the app yet? 

You can now access our region's forecasts, observations, and weather data directly from the Avy App (IOS; Android). Many features are accessible offline, so you can doublecheck danger ratings and travel advice on the drive to the trailhead or in the backcountry. 

Events and Education:

Want to start your New Year on the right foot? Sign up for a Partner Rescue Clinic for motorized Riders on January 4. Check out our calendar for other upcoming events. 

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