Bulletin d’avalanche

Jasper

Apr 3 – 4, 2013Parks Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

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

  If the forecast precipitation falls as rain rather snow expect the avalanche danger to rise rapidly at low elevations.Road closures after mid day along the Maligne Lake Road and Icefields Parkway can be expected if we see significant rain.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    These heavy and unstable features can fall unexpectedly triggering deep large avalanches. These are commonly, but not exclusively, found above east facing slopes at ridge top elevations.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    Cooling temperatures over the next 3 days will reduce magnitude, frequency and distribution of these events. Pay close attention to the increasing air temperature and met freeze crust thickness. When crusts are gone you should head for safer slopes.

  • Wet Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–3
    These events have been observed up to 2600m on south facing slopes. Cool temps over the next few days will reduce the magnitude and distribution. These events are most likely in the afternoon when the sun is out or during periods of significant rain.

Weather Forecast

A possibility of light rain at lower elevations and snow near treeline. Up to 30cm of new snow could fall by Saturday evening as cool easterly air is confronted by an upper elevation westerly flow. Valley bottom temperatures will warm during the day producing convective uplift and more snow. Glacial out flow will cool the valleys overnight.

Snowpack Summary

Below Treeline a supportive 15cm melt freeze crust provides temporary stability above a wet and unconsolidated snowpack. The crust thins with elevation and on slopes which are not South facing. By mid afternoon, or earlier on very hot days, this crust will melt and the avalanche danger will  increase considerably. The base of the snowpack is weak.

Avalanche Summary

Avalanche activity will be at its greatest by mid afternoon or during rain events. During the morning a strong crust prevents natural avalanches. As the crust melts the danger increases. At that time avalanches up to size 2 can be expected. Falling cornices can trigger full snowpack slabs of size 3 from the alpine. Cool temps reduce the danger.

Confidence

Freezing levels are uncertain

Régions couvertes