Bulletin d’avalanche

Jasper

Jan 20 – 21, 2013Parks Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Sun
Mon
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Winds have raked the landscape and not much left for winds to move. Good skiing is hard to find. If freezing levels are higher than forecasted for Monday, the danger rating may rise correspondingly. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Wind slabs have developed on a variety of lee aspects overlying a buried surface hoar in locations from Jan 6th. Avalanches have been observed on thin, steep, lee slopes in the alpine some with wide propagations or stepping down.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–4
    Wind slabs avalanches have triggered this weakness thus gaining significant mass. This situation will more likely occur in shallow snowpack areas. Less activity today due to cooler temperatures but expect some steep slopes remain primed. 

Weather Forecast

Sunday: ridgetop winds NW 40km/hr, surface freezing level with light snow. Monday: NW 75km/hr, 1900m freezing level, no snow and cloudy periods but mainly sun. Tuesday: SW 25km/hr, afternoon freezing level 1400m and no snow. 

Snowpack Summary

Extreme NW winds have stripped alpine and tree line fetch zones. Hard wind slabs are present on treeline and above lee slopes. Buried surface hoar is found at some locations 10-40cm down depending on windloading patterns. Weak basal facets dominate thin areas. Below tree line, the old storm snow is moist over rotten facets.

Avalanche Summary

On Friday, in the Whistler's area, numerous full depth natural slab avalanches occurred on thin, steep, lee alpine slopes. In the days preceding, we were seeing up to size 3 from wind loading. They were running far in paths with steep run outs. Saturday's patrol no new avalanches were observed on hy 93 as  slightly cooler temps helped to stabilize.

Confidence

Freezing levels are uncertain on Monday

Régions couvertes