Bulletin d’avalanche

Northwest Coastal

Nov 25 – 26, 2015Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Fri
Sat
Alpin
Sans niveau
Limite forestière
Sans niveau
Sous la limite
Sans niveau
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Points saillants

The snowpack is extremely variable depending on aspect and elevation and does not adjust well to rapid change. Watch for rising alpine temperatures to well above zero. Check out the Mountain Information Network. Give info, get info!

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Watch for new wind slabs on opposite slopes due to changing winds from the north. Destructive wind slabs from last weekends storm may still exist, watch for wide propagations, especially in the lee of ridgecrests.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Increasing and strengthening warm air aloft (above 1000 m) may deteriorate snow surfaces initiating loose wet avalanches. Smaller avalanches could dig down to deeper layers, especially at higher elevations, initiating larger slab avalanches.

Weather Forecast

The high pressure ridge continues to dominate the coastal regions. Strong alpine temperature inversions will be prominent with warm air above 1000 m ranging from 0-5 degrees. Moderate to strong outflow winds will prevail in coastal valleys. Valley cloud will accompany the strengthening temperature inversion. Outflow diminishing Saturday as pacific air starts to move into the north. By Sunday the weather pattern may see change, however; timing and intensity of the next Pacific system is hard to pin point due to disagreement between the Canadian model and the GFS.

Avalanche Summary

No new avalanche observations reported.

Snowpack Summary

The snowpack is extremely variable depending on aspect and elevation, with new wind slabs developing on reverse loaded southerly slopes and widespread surface crusts on all aspects at lower elevations. In the alpine, last weekends storm produced stiff wind slabs on northerly aspects, especially in the northern parts of the region. The snowpack doesn't adjust well to rapid change, so it may take several days to adjust and settle with the warm temperatures at higher elevations. Due to limited observations, I have very little confidence in what that underlying structure may be, although I suspect faceting, crusts and surface hoar may exist. However; how are they reacting as shears? Are they visually distinct and reacting like a cash register when tested? Or are they becoming hard to find with a more resistant shear characteristic? If I were traveling in the mountains, I'd maintain an investigative approach and dig down to test for weak layers before committing to a slope.

Régions couvertes