Bulletin d’avalanche

Jasper

May 7 – 8, 2019Parks Canada
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Archivé · expiré 7 years ago

Danger d’avalanche

Thu
Fri
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Points saillants

As Spring finally re-asserts itself, expect to see increasing activity with daytime warming. Meanwhile, incremental loading by small snowfalls has maintained winter-like avalanche problems on shaded slopes.

Problèmes avalancheux

  • Wind Slabs

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

    Wind slabs are more prevalent in the Marmot/Maligne areas than the icefields, as they received more recent snowfall and wind.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1.5–3

    Weak mid-pack facets, in isolated pockets on shaded, wind-sheltered alpine slopes. May also exist on shaded upper treeline features; and on solar aspects there is a (smaller) possibility of these failing on facets over a buried crust down 15-40cm.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Springs' increasing influence is encouraging the upper snowpack to shed recent snowfall, in loose snow avalanches. Snowballing or sticky snow are indicators of this problem.

Weather Forecast

Wednesday: A mix of sun and cloud. Treeline: High 4 °C. Ridge wind NE: 10-20 km/h. Freezing level: 2500m

Thursday: A mix of sun and cloud. Treeline temperature: Low 0 °C, High 9 °C. Ridge wind NW: 10-30 km/h. Freezing level: 3000m

Friday: A mix of sun and cloud. Treeline temperature: Low 4 °C, High 11 °C.  Freezing level: 3300m

Snowpack Summary

Regular small, warm snowfalls have sustained Windslab and loose snow avalanche problems. This recent snow is settling rapidly, but overlies crusts and facets in the upper snowpack. The crusts are thick/strong on solar aspects. Occasional whumpfing at upper treeline & alpine. The snowpack remains faceted on shady aspects, and weak in shallow areas.

Avalanche Summary

On Sunday, a large natural slab avalanche was observed at 2400m on a NE aspect. This was on Pyramid mountain near Jasper, and was most likely a recent Wind Slab (size 2.5). Numerous small (size 1), natural loose dry avalanches were also observed on steep shaded alpine terrain near Marmot Basin.

Confidence

Due to the number and quality of field observations

Régions couvertes