Bollettino valanghe

Flathead Range & Glacier NP

Flathead Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Riders remotely triggered a slab avalanche Wednesday, and wind-drifted snow may be reactive to the weight of a rider today. Sheltered terrain offers a softer and safer experience. As the day heats up, fresh rollerballs are a sign directing you to a different aspect or to end your day early. 

Problemi valanghivi

  • Wind Slabs

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

    Southwesterly winds continue to ramp up and will drift loose snow not capped by sun or rain crusts. Yesterday (Thursday), riders reported variable and gusty winds, meaning you might find pockets of drifted snow in unusual locations. Freshly formed slabs on persistent weak layers may break wider than expected, be remotely triggered, or wrap around terrain features.  Cracking around your skis or machine is a sign of wind-drifted snow and a good reason to fall back on safe travel techniques like riding one at a time while your partner watches.  You can further reduce your risk by selecting terrain that is sheltered from the wind.

    (1/12/2023)

    Blowing snow off the cornice along ridgelines.

Avalanche Discussion

A variety of surfaces makes for a mixture of potential hazards today. Where the snow surface is not capped by rain or sun crusts, anticipate pockets of wind-drifted snow. Likewise, in the absence of crusts, you can expect loose, dry snow affected by rising temperatures to moisten and potentially slide as a loose wet avalanche. Yesterday (Thursday), parties in the Flathead Range were able to navigate both these issues and find exceptional riding. Both parties reported gusty and variable winds, and one encountered widespread rollerballs running below 6000 feet due to rising temperatures and rain on snow.  

Surface hoar and faceted snow have been well documented during the recent dry weather. Snowfall last weekend buried these weak surfaces up to roughly one foot deep. A report of a remotely-triggered avalanche in the Northern Swan Range is our first indication of instability at the old snow surface and our first human-triggered avalanche since before Christmas. This slide occurred just below the ridge on a mid-elevation, wind-loaded slope. A quick hand pit is an efficient way to look for buried surface hoar or facets under the recent snow. Shooting cracks and whumpfing collapses are signals that these layers are sensitive to the weight of a skier. Consider moving to lower-angle terrain if you find these layers or encounter such feedback

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