Bulletin d’avalanche

Jasper

Dec 27 – 28, 2021
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Archivé · expiré 5 years ago

Danger d’avalanche

Tue
Wed
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Happy Holidays to everyone from Jasper Visitor Safety team! 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Up to 35cm of new snow Dec 22-23rd with moderate to strong winds created wind slabs on lee and cross loaded features. Winds have shifted Northerly so expect reverse loading patterns. A rain crust 30cm down is a suspect weak layer in BTL.

  • Loose Dry

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    A Dry loose problem persists with 35cm of new snow from Dec 23rd and ongoing accumulations from flurries. Extra vigilance is warranted in steep terrain, ice climbs, and gully terrain traps where small avalanches can build into significant volumes.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–3

    This problem, although stubborn, persists in isolated alpine terrain and may initiate with a large trigger or rapid loading. Use extra caution in thin areas were humans are most likely to trigger this high consequence layer.

Weather Forecast

Monday will be a mix of sun and cloud, no new snow, -22C and Westerly light winds. Tuesday will bring sun and flurries, -30 to -20 C, and light Northerly ridge winds. Wednesday will be similar to Tuesday.

Snowpack Summary

35cm of snow arrived Dec 22-23 with moderate to strong SW winds. Wind slab developed in the alpine and on exposed terrain features at treeline. The winds have shifted Northerly so expect reverse loading. The mid-pack is supportive with an exception of a weak rain crust 30-40 cm down found up to 1950m. Cold temperatures will accelerate faceting.

Avalanche Summary

Friday's avalanche control produced numerous 30cm thick wind slabs up to size 2 on wind loaded open tree line features. One result buried the road 2m deep for a 100m. Surprisingly, explosives did not trigger the deeper instabilities. Numerous loose dry explosive triggered and natural activity also occurred up to size 1.5. No patrols since 24th.

Confidence

Due to the number of field observations

Régions couvertes