Bulletin d’avalanche

Sea To Sky

Mar 23 – 24, 2012Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Sun
Mon
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

Strong solar radiation and mild temperatures this weekend will result in elevated avalanche danger during the day, particularly on sun-exposed slopes.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Wind slabs lurk below ridges, behind terrain features and in gullies. They may be buried by new snow, making them hard to spot.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–4
    Loose wet avalanches are likely on steep sun-exposed slopes during the day. There is potential for these heavy wet slides to step down to deeper weaknesses and create a large slab avalanche.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–8
    Persistent weaknesses still have the potential to create very large, destructive avalanches if triggered. Possible triggering mechanisms include a person/sled on a thin snowpack spot, cornice fall, or step-down avalanche.

Confidence

Fair

Weather Forecast

A ridge of high pressure should maintain sunny and dry conditions for Saturday and Sunday. Freezing levels should rise to 1500m on Saturday and 1600-1800m on Sunday, with cool temperatures overnight. Winds are generally light from the south. A weak system could bring light to moderate precipitation on Monday, but the timing and strength of this system is still a little uncertain. The freezing level should drop to around 1200m as the system approaches.

Avalanche Summary

Recent avalanche activity includes skier and explosive controlled avalanches to Size 1.5 from exposed wind-loaded features. The average depth was around 15-30cm. There were also several cornice failures reported but most did not trigger slabs below.

Snowpack Summary

Solar aspects are likely going through a melt-freeze cycle with frozen snow overnight becoming moist through the day. Snow and wind created fresh wind slabs and storm slabs on Tuesday. Heavy snow which fell last week is settling rapidly and gaining strength. Cornices are large and threaten slopes below. A persistent weakness, formed in mid-February, continues to produce hard, sudden planar results in snowpack tests. The likelihood of triggering this layer has gone down, but very large avalanches remain possible, which could be triggered by a shallower avalanche or cornice fall. The snowpack depth at treeline is 350-500cm.

Régions couvertes