Bulletin d’avalanche

Jasper

Apr 30 – May 1, 2013Parks Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

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

Good "dust on crust" skiing can be found on moderate terrain at treeline. Watch for the effects of daytime warming such as the snow becoming less supportive and snowballing. Solar warming will rapidly destabilize the snowpack increasing the danger.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–3
    Recent snow and strong NW winds will continue to build cornices. On failure deep releases  may run far into the valley bottom. With poor visibility high in the mountains stay well back from potential cornice features above steep drop offs.

  • Loose Dry

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2
    The recent storm snow will be sluffing off steep terrain as point release avalanches. Typically this is of most concern to alpine and ice climbers who need to be particularly mindful of this hazard under the current conditions.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    40cm of storm snow has fallen in the past 72hrs. West and NW winds have moved this snow onto lee aspects. South facing aspects are particularly likely trigger areas where the bonding of the new snow to the old melt freeze crust is weakest.

Weather Forecast

A continuation of the cool W & NW upper air flow pattern with strong winds. Temps will drop below freezing overnight in the valley bottom and remain cool at treeline elevations with a freezing level in the afternoon close to 1800m. This will creep higher into the alpine as the weekend approaches. Localized convective snow flurries are anticipated.

Snowpack Summary

40cm of new snow has fallen in the Icefields area since Saturday. This has formed pockets of windslab at and above treeline. Bonding of this slab on Southerly slopes should be considered suspect. Below the new snow  thick melt freeze crust layers cap isothermal snow below. Sun crusts extend high into the alpine on South facing slopes.

Avalanche Summary

With limited visibility at and above treeline no recent avalanches observed have been reported. Spindrift loose snow avalanches can be anticipated from steep and rocky terrain at treeline and above. Bonding between the new storm slabs and the old sun crust should be regarded as touchy with the potential of trigger of slab avalanches is possible.

Confidence

Timing or intensity of solar radiation is uncertain on Thursday

Régions couvertes