Bollettino valanghe

Flathead Range & Glacier NP

Flathead Avalanche Center
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Pericolo valanghe

Sat
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
1 · Debole
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In sintesi

Dangerous conditions exist at mid and upper elevations today because of widespread wet snow avalanche hazards. Triggered and natural wet snow avalanches are likely on steep slopes; these can run long distances and endanger you even in low angle terrain. Safe riding today means staying off of and out from under steep slopes, corniced ridges, and glide cracks.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2.5

    With a shallow-at-best refreeze overnight, wet snow avalanches are likely on and below steep slopes at mid and upper elevations. These may be largest in terrain that typically stays cold enough to preserve dry snow, because more snow has accumulated in this terrain since early April. Roller balls and pinwheels of wet snow fanning downslope are a clear sign that the snow surface is wet and unstable. Avoid traveling on or below steep slopes where you see these. You can't mitigate your exposure to this hazard by timing your travel today, because of the lack of refreeze overnight.

    (4/7/2022)

    The snow in terrain like this will be wet today, and long-running loose wet avalanches have replaced wind slabs (note crown) as the primary hazard. Note the glide cracks lower on the face.

    Photo: Zach Miller/ USGS

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Don't linger under cornices, even those well above you or at upper elevations. These are weakening and sagging in the balmy temperatures, and the chances of large chunks falling off are increasing. If you're traveling on a ridge, stay well away from the leeward side, because cornice chunks can snap surprisingly far back from their edges.

    (4/3/2022)

    Large seasonal cornices still cap many ridgelines in the Middle Fork despite recent warm sunny weather.

    Photo: Mark Dundas

Avalanche Discussion

After a cold morning, freezing levels spiked above 8000 feet overnight. Temperatures at mid and upper elevations remain in the mid 30s this morning. A shallow inversion is in place, with temperatures below freezing at stations below about 4000 feet. Wind speeds have been in the mid teens above about 7000 feet, but light below that.

A party near Marias Pass Thursday reported existing melt-freeze crusts softened rapidly mid day, thanks to intense solar radiation. They also reported some small wet snow sluffs on south and east aspects. I doubt the snow surface refroze solidly overnight, even with clear skies. That means no window today before wet snow avalanches become a hazard. Triggering wet loose avalanches will be likely on all aspects at mid and upper elevations from the get-go today, with natural slides possible. These will mostly involve snow that's accumulated above the early April melt-freeze crust. They'll be largest on shaded aspects, where the 4-20 inches of recent snow is wetting for the first time. Slides in this terrain could definitely entrain enough wet debris to be dangerous, particularly on slopes with long, continuously steep pitches. 

The warming probably hasn't been sustained enough to create a wet slab avalanche problem. We've had scattered reports of glide cracks opening, and a few of these could fail with this warming. Stay out from under frowning cracks. These don't seem as widespread this season as usual. Most reports have been from slopes that face east through south to west.

Cold temperatures arrive tonight, shutting off meltwater production altogether Saturday. A few inches of new snow tonight and more tomorrow will make for a return to winter avalanche hazards this weekend. Likely Wind Slab and Loose Dry avalanche problems. Temperatures may bottom out in the single digits Sunday. Yes, that cold. A more significant low pressure system may develop early next week. 

Sunday, April 10 marks the last daily avalanche forecast for the season. We'll continue to issue conditions updates as needed into early May. Expect these at least twice a week, though we'll publish more frequently if conditions warrant. We'll post these in the afternoons.

Regioni coperte