Bulletin d’avalanche

Jasper

Mar 23 – 24, 2017Parks Canada
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Archivé · expiré 10 years ago

Danger d’avalanche

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

Several triggers are at play including solar radiation, wind loading and falling cornices. Pay close attention to changing condition, particularly warming, after all it is spring time.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–3
    Significant snow is available for transport at treeline and above as witnessed at the Icefields today.  Avalanche to size 2.5 have been observed and may step down to deeper layers  running far into the valley below. Bonding appears to be improving.

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–3
    Large cornices on lee features with some visibly detached. Those that may release would likely trigger a large avalanche. Give them a wide berth.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–4
    The lower snowpack is riddled with weaknesses particularly where the  snow  is shallow over rocky terrain.  Today a  large cornice failure triggered a size 3 slab on a NE treeline feature. Debris is running far into the valley bottom.

Weather Forecast

Unsettled weather with a SW flow L-S winds. Tree line highs -5, Lows -10. Some sunny periods and up to 10cm of snow. Icefields freezing level between 1,450m and valley bottom.

Snowpack Summary

Thick wind slabs at and above treeline which stiffen into alpine. Large cornices are present. The mid-pack has several weaknesses but is providing some bridging strength above the weak base. This is highly faceted with a lingering rain crust and depth hoar below. On southerly slopes a melt freezing crust is developing as the pack warms.

Avalanche Summary

Although the visibility was poor several new slab avalanches were recorded at treeline and into the alpine. A class 3 triggered by a falling chunk of cornice on a NE facing slope. A size 2 from a S facing slope was likely triggered by solar radiation. A skier appeared to have triggered another size 2 on a N slope.

Confidence

Timing or intensity of solar radiation is uncertain on Saturday

Régions couvertes