Bulletin d’avalanche

Jasper

Apr 5 – 6, 2017Parks Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

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

Cautious route-finding and conservative decisions is critical  the next few days. Thursday to Friday's precipitation will be rain at lower elevations raising the potential for loose wet avalanches below  treeline locations.   

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    Expect wind-slab formation by current strong SW winds particularly off alpine ridges and cross-loaded gullies. If triggered, could step down to the deep persistent slab.

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3
    Cornice failure is hard to predict but is more likely with inputs like solar radiation and wind-loading. Some very large cornices out there.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–4
    This problem is unlikely to disappear. It can be triggered by large loads like cornice fall or wind-slab avalanche. Human triggering is most likely from shallow spots or on steep unsupported slopes.

Weather Forecast

Thursday to Friday freezing level may be 2200m, rain in valley bottom with possibly 15cm of snow in higher elevations by Friday afternoon. Winds may shift Easterly on Friday afternoon with a second pulse of precipitation. Possibly a slight cooling trend on Saturday.

Snowpack Summary

Good skiing between 1900-2400m in sheltered areas. Wind-slab along lee ridge-lines and cross-loaded gully features from strong SW winds. Mid-pack bridging basal weakness. Lower snowpack is weak with a combination of facets, Nov rain crust and depth hoar. Below tree line a supportive 20cm melt freeze crust sits above a weak facet layer to ground.

Avalanche Summary

Helicopter flight from Jasper to Sunwapta Resort to Maligne. No new avalanches noted on this flight and visibility was good but very windy at ridge-tops. Tuesday's Bald Hill patrol also did not note any new avalanches. Previous cornice and wind-slab failures have triggered the deep persistent slab resulting large full path avalanches.

Confidence

Freezing levels are uncertain

Régions couvertes