Bulletin d’avalanche

Jasper

Dec 12 – 13, 2012Parks Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
1 · Faible
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Points saillants

Touchy wind slabs are found on a wide range of aspects.  Stick to sheltered tree line slopes or glades for the best turns. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–3
    Wind slab is present on all open lee slopes from the alpine into tree line elevations. Several natural slab avalanches have been observed on this layer today.  Watch for reverse loading patterns and increasing natural activity.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–3
    A persistent facetted weakness can be found around a mid-pack crust.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–3
    Slab avalanches and large cornice failures have triggered this weakness on E to W aspects in the alpine.  Shallow snowpack areas  and along the edges of snow pockets will be likely trigger spots.

Weather Forecast

Moderate NW winds will ease through Wednesday to light from the SW by the afternoon.  A few cm of snow are possible overnight and through the day on Wednesday.  Expect seasonal temperatures (Highs -8, Lows -15) and cloudy skies.

Snowpack Summary

Moderate to strong winds have continued, shifting from the NW to the SW.  Wind slab can be found on most lee slopes extending from the Alpine well into tree line elevations.  Expect variable wind loading patterns as directions vary with local terrain influences.  Cornices are well developed.

Avalanche Summary

An avalanche cycle has occurred in the past 24-48 hrs.  Slab avalanches to size 3 have occurred on E to W aspects at alpine and tree line elevations and have stepped down to the basal facet layer.  Large cornice failure has triggered large avalanches on the basal facet layer as well.  Winds will ease, however, expect touchy conditions to continue.

Confidence

Due to the number and quality of field observations

Régions couvertes