Bulletin d’avalanche

Jasper

Feb 24 – 25, 2019Parks Canada
Voir sur la carte
Archivé · expiré 8 years ago

Danger d’avalanche

Mon
Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
Ouvrir la carte complète

Points saillants

Fresh windslabs have formed on a variety of aspects on the 93N, while surface snow remains unaffected by wind in the Marmot / Whistler / Tonquin Creek region.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2.5
    Strong SW winds blew for 24 hours yesterday in the columbia Icefields area, and have now switched to steady moderate from N. In the southern areas of the bulletin region, expect a cornucopia of windslabs on a variety of aspects.

  • Loose Dry

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1–1.5
    This problem is probably isolated to terrain where surface snow doesn't show signs of previous wind affect : all elevations at the north end of the bulletin region, but only lower elevations in the Columbia Icefields region

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1.5–3
    Although natural deep persistent slab avalanches have been few and far between lately, they are still possible in isolated places. Steep, unsupported, and thin/variable depth are factors to be wary of.

Weather Forecast

Sunday will be sun with clouds, no precipitation, Treeline Low -21, High -16, and light ridge winds. Monday will be similar, but with alpine temperatures dropping and winds rising toward moderate through the afternoon.  Little change for Tuesday, except the coldest morning of the lot! Mountain weather forecast available at Avalanche Canada.

Snowpack Summary

Fresh windslabs have formed in exposed terrain, lee to SW then N winds.  Remnants of a surface hoar layer (Jan 18) down 40cm could be reactive in isolated areas treeline and below. A strong midpack exists in thick snowpack areas, but is weaker in thinner snow-pack zones over weak basal depth hoar, consistently giving hard, sudden results in  tests.

Avalanche Summary

No field patrol Saturday, nothing new reported. Thursdays field team (Nigel Pass area, Columbia Icefields Region) observed two avalanches triggered by small cornice failures;  one triggered a size 1.5 deep persistent slab  (steep, unsupported N aspect, at 2700m), the other triggered only a loose dry avalanche in a large planar slope.

Confidence

Wind effect is extremely variable

Régions couvertes