Bulletin d’avalanche

Northwest Coastal

Feb 6 – 7, 2016Avalanche Canada
Voir sur la carte
Archivé · expiré 11 years ago

Danger d’avalanche

Mon
Tue
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
4 · Fort
Ouvrir la carte complète

Points saillants

Stormy conditions are elevating the avalanche danger to HIGH. Strong winds, rising freezing levels and heavy precipitation may trigger very large avalanches.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–6
    Heavy storm loading from snow or rain may trigger deeply buried persistent weak layers resulting in very large avalanches with wide propagations.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–4
    A potent storm forecast for Sunday and Monday will form deep and reactive storm slabs. Storm slabs may be extra touchy due to recently buried surface hoar.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    Heavy rain forecast for Sunday and Monday will promote loose wet avalanche activity in steep lower elevation terrain. Destructive wet slab avalanches are also possible.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Sunday

Weather Forecast

On Sunday and Monday another wet, warm and windy storm will impact the region. Expect between 30-50mm of precipitation per 24 hour period with freezing levels climbing from 500m on Sunday morning to 1800m by Monday afternoon. On Tuesday, expect a mix of sun and cloud with the freezing level shooting up to 2500m. Ridgetop winds should remain strong to extreme from the southwest for the forecast period.

Avalanche Summary

Avalanche observations have been quite limited in recent days, mostly due to stormy weather. However, in the mountains near Stewart fairly widespread storm slab activity (mostly size 2 with a few to size 3) was reported on Friday. Looking forward, a juicy storm on Sunday and Monday is forecast to promote widespread storm slab avalanches. New snow will also increase the likelihood of destructive persistent slab avalanches. At elevations where rain falls loose wet and wet slab avalanches are also likely.

Snowpack Summary

A warm, wet and windy storm forecast for Sunday will create deep new storm slabs throughout the day adding to an ongoing storm slab problem. Freezing levels are expected to rise dramatically throughout Sunday leaving surfaces at treeline and below saturated by the afternoon. Recent storm accumulations may be especially touchy as they are sitting on a new surface hoar layer that was buried on February 3rd. The January 9th surface hoar/facet layer is down 70-150 cm in most places, and remains a concern on all aspects and elevations, 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, warming and forecast heavy storm loading will increase the likelihood of triggering these layers where they still exist. A conservative approach to mountain travel is still required.

Régions couvertes