Boletín de aludes

Kootenay Boundary

Mar 13 – 15, 2020Avalanche Canada
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Archivado · caducó 7 years ago

Peligro de aludes

Sun
Mon
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Lo esencial

New snow and strong east wind will form new wind slabs in exposed terrain. This snow is continuing to load buried weak layers that have surprised people.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible - Likely
    Tamaño
    1–2

    Around 5 to 15 cm of snow is forecast for the region, with the most forecast for Kootenay Pass and for the Okanagan Valley. The snow will fall with strong easterly wind. East wind is atypical, so you may find wind slabs in terrain features that don't typically have them. This snow will further load deeper layers, meaning there is potential for step-down avalanche activity.

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1.5–2.5

    Around 60 to 80 cm of snow overlies a weak layer of surface hoar. This layer has been most problematic on northwest to northeast aspects between 1600 m and 2300 m, but it may exist on all aspects and at all elevations. Assess the layer prior to committing to avalanche terrain or adopt a conservative mindset to avoid the problem.

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

FRIDAY NIGHT: Cloudy with snowfall, accumulation 5 to 10 cm, moderate to strong east wind, alpine temperature -17 C.

SATURDAY: Cloudy with snowfall then clearing, accumulation 2 to 5 cm, light to moderate east wind, alpine temperature -16 C.

SUNDAY: Clear skies, light northeast wind, alpine temperature -10 C.

MONDAY: Clear skies, light northeast wind, alpine temperature -5 C, freezing level rising to 1500 m.

Avalanche Summary

A few wind slab avalanches were triggered by humans on Friday. They were in alpine terrain and on north and east aspects, about 40 cm deep. One of the wind slabs stepped down to the surface hoar layer described in the Snowpack Summary.

Many wind slab avalanches were triggered by explosives and naturally on Thursday. They occurred on all aspects, at alpine elevations, and were 20 to 40 cm thick.

Widespread avalanche activity is starting to quiet down on the surface hoar layer described in the Snowpack Summary. Over the past two weeks, small to large (size 1 to 2) avalanches have released on this surface hoar layer. They have most often released between 1800 and 2300 m on northwest to east aspects.

Snowpack Summary

Snowfall and strong easterly wind will form new wind slabs in exposed terrain. This wind direction is atypical, so terrain features that don't typically have wind slabs may this weekend. Wind slabs may still linger in north to east terrain from the storm earlier in the week.

The upper snowpack is relatively complex. A few different layers of surface hoar and melt-freeze crust exist, which have recently acted as sliding layers. One such layer buried about a week ago may be found about 20 to 40 cm deep. The most widespread layer was buried late February and is now buried 60 to 80 cm. This layer is most commonly found in open trees (e.g. in this MIN) or sheltered terrain around the upper part of below treeline, treeline, and lower alpine elevations. This layer may only remain a concern in the north and east parts of the region.

The remainder of the snowpack is strong and well-settled.

Terrain and Travel

  • Watch for avalanche hazard to increase throughout the day.
  • Use careful route-finding and stick to moderate slope angles with low consequences.
  • Avoid freshly wind loaded terrain features.
  • Be aware of the potential for large avalanches due to the presence of buried surface hoar.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

Regiones cubiertas