Bulletin d’avalanche

Northwest Inland

Jan 13 – 14, 2013Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Tue
Wed
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Be aware of rapid warming already happening and forecasted solar radiation which will weaken the snow surface and possibly act as an avalanche trigger.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–5
    Be aware of rapid warming and solar radiation which will weaken the snow surface, possibly triggering an avalanche on the surface hoar layer down 80 cm or down to the deeper persistent weak layer from early November.

Confidence

Poor - Intensity of incoming weather is uncertain

Weather Forecast

Sunday night and Monday: The ridge of high pressure that has brought cold temperatures lately is being replaced by a warm front pushing in the interior at the end of the day making temperatures warm up significantly, bringing freezing levels unseasonably high and an inversion will keep  the peaks above zero degrees as well. Cloud cover should also dissipate in the alpine with some mid-level clouds. Winds are forecasted to be strong from the Northwest.Tuesday: Similar situation for Tuesday with alpine temperatures being well above normal and strong sun radiation. Winds are expected to be strong from the Southwest.Wednesday:  Temperatures should start cooling in the alpine and a couple disturbances could bring some light precipitation with light Southwest winds.

Avalanche Summary

Numerous glide cracks and a few size 2 avalanches were reported at treeline and below treeline.

Snowpack Summary

The upper snowpack instabilities will most likely become unstable again with the rapid warming that has already started and additional solar radiation on Tuesday. The trigger of a surface instability could step down to the deeper persistent instability creating bigger avalanches. Read the forecaster's blog to learn more about this process. Indeed, the 25 cm of last week's snow is sitting over a weak, faceted old snow surface and a surface hoar layer in some areas. Loose dry sluffing is likely in steep terrain sheltered from the wind. In wind-affected areas, wind slabs have formed behind terrain breaks such as ridges and ribs. A strong mid-pack overlies a weak base layer of facets and the remnants of a crust.

Régions couvertes