Lawinenlagebericht

Flathead Range & Glacier NP

Flathead Avalanche Center
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Lawinengefahr

Sat
Hochgebirge
1 · Gering
Waldgrenze
1 · Gering
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

You're likely to encounter wind-stiffened snow on exposed, upper elevation slopes. Many drifts will be old and hard; a few little slabs may have formed over the past two days. Though you probably won't trigger a slab large enough to injure you, assess leeward terrain for cracking in stiff snow before stepping out. Sheltered, shady, mid-elevation slopes offer soft snow, better riding, and less hazard.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely
    Größe
    1–2

    Wind-hardened snow is widespread above about 6500 feet. Cam and I rode wind-affected slopes on Mt. Brown Wednesday and only triggered tiny drifts. Cam was in the Swan Thursday and found similar conditions. The caveats are on isolated, steep terrain at the highest elevations. Very large avalanches ran from upper elevation, leeward terrain in the Flathead/Glacier Park zone on Monday or Tuesday when new snow and wind built drifts on top of crusts or weak facets. A few small slabs may have developed since then near upper elevation ridgelines and in the tops of couloirs. Assess that kind of terrain if you step out onto steep, upper elevation slopes.

    (3/9/2022) null Photo: Clancy Nelson

Avalanche Discussion

Observers have reported several large to very large slab avalanches running from upper elevations in the Flathead Range and central Glacier Park. These likely ran early in the week during the last wind and snow event. They may have failed due to wind drifted snow forming cohesive slabs on top of near-surface facets and crusts. Though these broke widely, they appear to be isolated. Thursday, one observer sent us a picture of blowing snow in the Essex area, while another skied Snowshed Mountain and found zero signs of instability to their high point of 7300 feet. Riders have been finding wind-affected snow above 6500 feet for a few days now, but they’ve been mentioning crumby riding conditions more than instability. Winds continue to blow from the west into Saturday. A few inches of new snow Friday night may add fuel to the slab machine allowing fresh small drifts to develop. 

Below about 7400 feet, thick hard crusts are covered by 3 to 16 inches of snow from early in the week. The recent snow is deepest at upper elevations and further north. Guy and blase found up to 24 inches in the northern Whitefish on Tuesday, Cam and I found up to 6 inches on Mt. Brown Wednesday. Thursday, riders found 8 in the Swan range (example 1, example 2). It’s dust on crust below about 5500 feet. You can expect to find soft snow and good riding in terrain sheltered from the wind and sun. Solar aspects have a sun crust at or near the surface. 

The Friends of The Flathead Avalanche Center and FVCC are hosting the last Intro to Avalanches next weekend. And on March 22, join us online for a Community Chat where we review recent conditions and debrief a near miss.

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