Bulletin d’avalanche

Northwest Coastal

Feb 10 – 11, 2016Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

A gradual cooling trend with forecast precipitation, should bring snow to the alpine and then slowly to lower elevations. Persistent weak layers continue to be a concern for large destructive avalanches.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–6
    Recent storm loading, solar radiation and skyrocketing freezing levels have increased the likelihood of waking-up deep and destructive persistent weak layers. Cornice falls may also trigger a persistent slab avalanche.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    New storm slabs are expected to develop with forecast new snow and wind.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    Elevated freezing levels may promote ongoing loose wet avalanche activity. Loose wet avalanches may also step down to deeper, more destructive layers

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Expect 5-10 cm of new snow above 1200 metres overnight combined with strong southwest winds. Chance of broken skies on Thursday with moderate-strong southwest winds. 5-10 cm by Friday morning with moderate southerly winds and freezing levels around 1200 metres. Light precipitation and moderate southwest winds continuing during the day on Friday. Another light pulse of precipitation early Saturday morning with moderate southwest winds and freezing levels down to about 600 metres.

Avalanche Summary

No new reports of avalanche activity. Reports of activity during the recent storm of slab avalanches up to size 4.0 releasing in the storm snow or on the deeply buried persistent weak layer from early January. Cooling with help reduce avalanche activity; however, the forecast cooling trend is so gradual it's tough to say exactly when or to what extent.

Snowpack Summary

On Sunday a warm, wet and windy storm added mass and reactivity to recently formed storm slabs. 24 hour snow totals were around 40cm in the Terrace area with closer to 70cm falling in the mountains around Stewart. Rain on Monday, and then rising freezing levels and solar radiation on Tuesday have likely left most surfaces moist or wet. This warming has had a significant destabilizing effect on the snowpack. The January 9th surface hoar/facet layer is down 70-200 cm and remains a concern, especially with heavy and/or thin-spot triggers. Around the same depth you may also find a surface hoar/facet interface from around New Years. There continues to be a lot of uncertainty regarding the reactivity and distribution of this destructive persistent avalanche problem; however, warm temperatures have increased the likelihood of triggering these layers where they still exist. A very conservative approach to mountain travel is still required.

Régions couvertes