Bulletin d’avalanche

Jasper

Dec 8 – 9, 2024Avalanche Canada
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Archivé · expiré 2 years ago

Danger d’avalanche

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

Points saillants

Up to 25cm of new snow and strong winds have formed windslabs in leeward areas. Avalanches may have the potential to step down to deep persistent instabilities.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2.5

    New snow and increased south and southwest winds have developed windslabs in leeward features. The new snow needs time to settle and bond. Avoid wind loaded pockets and avoid being under slopes that the wind is loading.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1–2.5

    This layer is most reactive where it has been loaded by wind transported snow. This problem includes the Oct 18 crust and the Nov 8th crust and surface hoar. There’s uncertainty around its distribution and sensitivity.

Confidence

Moderate

Avalanche Summary

Avalanche control on Saturday December 7th produced windslabs up to size 2 near Parkers ridge.

At Marmot Basin size 2 avalanches have been produced that are failing on the facets above the October 18 melt-freeze crust, over the past couple days . These have been produced by large explosives in the alpine.

Snowpack Summary

Up to 25cm of new snow sits on a thin melt freeze crust. Strong winds have redistributed this snow into windslabs that may fail on the crust or on deeper layers. Three weak layers exist in the snowpack; the Nov 8th crust and facets that are down 30-40 cm at tree-line and below, surface hoar that has been found down 70cm at 2500m and the October crust which is found near the base of the snow pack with facets above and below. Snow depth is roughly 80 cm at treeline and tapers rapidly below.

Weather Summary

Sunday

A mix of sun and cloud with isolated flurries (trace). Alpine High -8 °C with mostly light ridge wind occasionally gusting to 45 km/h. Freezing level at valley bottom.

Monday

A mix of sun and cloud. Alpine Low -13 °C and High -10 °C. Ridge wind west (10 km/h). Freezing level at valley bottom.

Terrain and Travel Advice

  • Be mindful that deep instabilities are still present in the snowpack.
  • Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.

Régions couvertes