Bulletin d’avalanche

Northwest Coastal

Jan 16, 2019Avalanche Canada
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Archivé · expiré 8 years ago

Danger d’avalanche

Thu
Fri
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Danger will be highest on slopes that face the sun and where winds have recently blown the snow into slabs. Expected outflow winds could locally increase avalanche danger.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–2.5
    Wind slabs from the previous storm exist on north to east aspect. Outflow winds blowing from the east may set up new wind slabs on westerly aspects where new snow is available for wind transport.

Confidence

Moderate - Wind speed and direction is uncertain

Weather Forecast

TUESDAY NIGHT: Dry with clear spells. Cooling.WEDNESDAY: Dry with a mix of sun and cloud. Treeline temperatures around -5C. Easterly outflow winds are expected at 1300 m and below in large valleys that drain towards the west; in other areas winds are expected to be light.THURSDAY: Dry with a mix of sun and cloud. Treeline temperatures around -8C. Easterly outflow winds continuing.FRIDAY: Dry with cloud increasing through the day. Treeline temperatures around -8C. Moderate southeasterly winds.

Avalanche Summary

Storm slab avalanches up to size 3 continued to be reported into Sunday due to the warm and wet storm that has affected this region. Storm and wind slabs are likely gaining strength, except on slopes facing the sun and where wind effect is pronounced.An avalanche incident was reported in the Shames backcountry area last Thursday. The incident involved two skier triggered avalanches occurring in succession with two people involved and partially buried. The details can be found on the Mountain Information Network. (here) An very large (size 3.5) natural avalanche occurred in the north of the region on Sunday that is believed to have initiated on a buried layer of surface hoar then stepped down to the weak layer from early December.

Snowpack Summary

A warm and wet storm brought up to 100 mm precipitation between Wednesday and Sunday last week, with rain falling as high as 1500 m. Precipitation has now ended and temperatures have started to cool. New snow from the storm is likely to have blown into wind slab deposits at higher elevations. The snow is crusty at lower elevations.In some sheltered areas the new snow is sitting on a weak layer of surface hoar (feathery crystals). For most of the region, a weak layer of facets (sugary snow) buried in early December exists down 180-250 cm. The likelihood of triggering this layer is decreasing, but it could be triggered by humans in shallow snowpack areas, particularly in the north of the region. The potential may also exist for storm slab avalanches to step down to this layer, resulting in large avalanches.

Régions couvertes