Bollettino valanghe

Banff Yoho Kootenay

Dec 28 – 29, 2025Avalanche Canada
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Archiviato · scaduto 9 months ago

Pericolo valanghe

Tue
Wed
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole

In sintesi

Snowfall has finally ended but the snowpack will still take time to adjust to the recent loading.

Use extra caution when approaching or exposed to alpine terrain where windslabs are fresh, and the deep persistent slab problem is the most prevalent.

Temperatures are cold. Factor this into your decision-making.

Problemi valanghivi

  • Wind Slabs

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

    Moderate- strong southerly and westerly winds have created fresh wind slabs in alpine and open treeline terrain as the significant amounts of recent snow are redistributed. Lake Louise had small soft slabs that propagated well up to sz 1.5. SSV reported several sz 1s that ran far but started slow.

  • Loose Dry

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely - Very Likely
    Dimensione
    1–1.5

    New snow has piled up in mushrooms, rock faces, and along ridge crests. Manage your sluff carefully and consider others in steep terrain. Climbers should be cautious about getting pushed off, even in relatively small terrain.

    Remember, these events could trigger the other avalanche problems.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–4

    The natural avalanche cycle on this layer has ended but concern for skier triggering on this layer remains. The natural and controlled avalanches observed on this layer have often been large with many reaching below treeline terrain. Be wary of shallow areas: triggering 'thin to thick'.

Confidence

Avalanche Summary

Helicopter avalanche control on the 93S at Mt Whymper and Vermilion Peak produced mainly small slabs up to sz 2 within surface instabilities. Vermillion Peak S had a sz 2.5 that remoted into a thin area on the upper face and ran far. No results with Gasex on Mt Bourgeau last night.

The SSV ski patrol reported the Bourgeau Right-Hand avalanche path went sz 3 at approx 15:00 Saturday afternoon. Investigation of the start zone indicates this was likely triggered by goats.

Snowpack Summary

10-20cm of snow overnight brings storm totals to 30-60 cm in the last 4 days, while moderate southerly and westerly winds have created fresh windslabs in alpine and open treeline terrain.

There is 40-80 cm over the Dec 15 melt-freeze crust (which is present to ~1800 - 2000m).

The significant snow load that accumulated so far this December continues to settle over the weak November facet/crust interface now down 80-160 cm.

Treeline snow depths range from 100-200cm plus.

Weather Summary

As a high-pressure system takes over. Clear and cold replaces the prolonged snowy weather we have had.

A northwest flow will bring light winds overnight that may increase Sunday to moderate at ridgetop. Temperatures increase from near -20C at valley bottom to -15C through the day.

Sunday evening may bring a further increase in the temps and in the winds, which will shift to west.

Link to weather forecast

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
  • Be mindful that deep instabilities are still present and have produced recent large avalanches.

Regioni coperte