Bollettino valanghe

Banff Yoho Kootenay

Mar 17, 2019Parks Canada
Vedi sulla mappa
Archiviato · scaduto 8 years ago

Pericolo valanghe

Mon
Tue
Alta quota
4 · Forte
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
Apri la mappa completa

In sintesi

Watch for solar heating to weaken the snowpack Sunday with a rise in the freezing levels to follow. Surface slabs and sluffs have been serious enough in the last several days... there is significant uncertainty as to how deeper weak layers will react

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2.5
    Strong SW-W winds have built wind slabs in open areas above treeline. In may cases, these slabs initiate a larger loose dry avalanche as they run. In a few examples these slides have gouged to the deep persistent layers near the base of the snowpack

  • Loose Dry

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2.5
    The faceted snow is easily initiated as a sluff in steep terrain that will entrain all available loose snow until it hits lower angled terrain. If a windslab or cornice initiates these, expect increased width, mass, momentum and reach.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1–2
    While moist snow avalanches will start to become a problem themselves at lower elevations, as solar heating starts to take hold, consider a wider range of possible triggers to be available for the avalanche problems at upper elevations as well.

Weather Forecast

Despite a stiff breeze and thin cloud Saturday, solar heating was strong. Sunday will dawn clear and winds will likely diminish: expect a significant solar shock to the snowpack. This begins a significant warming trend that will bring freezing levels to 3000m later in the week. Both size and likelihood of avalanches are expected to increase.

Snowpack Summary

15- 50cm has accumulated since March 7. Modertate to strong SW-W winds have redistributed this snow treeline and above. This snow sits over previous widespread wind effect in the alpine, suncrusts on steep S aspects and 30-50cm of sugary facets everywhere else. While a tough midpack exists in thicker areas, facets to ground are seen in many others.

Avalanche Summary

Several Natural (eg 1, 2) and human triggered eg (1, 2) slabs have been seen over the last two days. South aspects have been the most active: increased sensitivity due to solar heating, buried crusts, and slab formation due to rapid settlement are all likely factors here. Loose wet activity also started up at around 15:00 as solar heating peaked.

Confidence

Timing or intensity of solar radiation is uncertain on Sunday

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