Bulletin d’avalanche

Northwest Inland

Dec 4 – 5, 2011Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Tue
Wed
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Big westerly winds combined with new snow will create fresh sensitive windslabs on lee aspects. These new windslabs will be burying old hard windslabs that may still be sensitive to human triggers.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    Storm slabs will be an increasing problem throughout the day Monday. Carefully re-evaluate each run to account for changing conditions.

Confidence

Poor - Due to limited field observations

Weather Forecast

A radical above freezing layer is forecasted for Sunday night into Monday. Freezing levels as high as 2800m are possible. A cold front sweeps across the NW coast bringing as much as 30mm to the more coastal locations Monday afternoon as ridgetop winds build to 80 - 95 km/h out of the W. Freezing levels lower Monday as the cold front moves inland.Cold post frontal air keeps the region dry & cool on Tuesday. Ridge of high pressure rebuilds Wednesday & Thursday with an outflow pattern. Another above freezing layer is forecasted for later in the week.

Avalanche Summary

Natural and explosive controlled avalanches up to size 4.0 releasing in the storm snow. Some of the larger releases have been from glide avalanches. Most of this activity is in the West of the region closer to the coast. We don't have any new reports from the Interior.

Snowpack Summary

Very strong W-SW winds have probably wreaked havoc in any exposed terrain. Expect to find scoured areas, sastrugi, and hard or stiff wind slabs. The average snowpack depth at treeline is over 200cm. The mid and lower snowpack are generally quite strong. Watch for clues of instability like whumpfs or shooting cracks, and if observed back off any steeper objectives.

Régions couvertes