Bulletin d’avalanche

Jasper

Apr 9 – 10, 2014Parks Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

Pay Close attention to daytime warming and wind slab development. Good skiing can be found between 2,300 - 1,800 m in sheltered lower angle terrain.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Strong South and Westerly winds are transporting the 10-15cm of new snow from the 8th. Rain fell below 1,800m. Field tests at 2,300m produced an easy shear above an old sun crust on the 9th. At lower elevations the slab is less well developed.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    Solar effect and day warming will destabilize the snowpack on all slopes in the valley bottom. The danger will increase as it does. Travel below 1700m will be ugly. With increasing elevation and slopes that don't face south this effect will diminish.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–3
    Most avalanches regardless of initial form are stepping down to ground. These are most common from shallow snowpack areas where there is little bridging strength in the midpack and the thermal energy is greatest. Rocky areas are also dicey.

Weather Forecast

Below freezing overnight temperatures into the weekend with day time freezing levels not extending into the alpine. Some snow may arrive on Friday and into the weekend. Winds will be westerly over the next 36 hours.

Snowpack Summary

At treeline and below warming temperatures and rain has increased the temperature of the snowpack. Moist snow in the upper pack can be anticipated. Surface crusts will form when temps drop. Solar facing slopes close to treeline may have buried crusts with slab snow above. Deeply buried weaknesses near ground. Windslabs in the alpine & treeline.

Avalanche Summary

Slab avalanches observed Tuesday and Wednesday up to size 2.5 from treeline and low alpine. All events are stepping to ground. Most are being triggered by wind loading with one cornice failure. Strong WSW winds are developing wind slabs. Afternoon warming and solar radiation is producing point and wet slab releases from below treeline.

Confidence

Timing or intensity of solar radiation is uncertain on Thursday

Régions couvertes