Bulletin d’avalanche

Waterton Lakes

Apr 7 – 10, 2014Parks Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Even short periods of solar heating or rain may cause an increase in the hazard beyond the posted Danger Ratings. Be conservative Tuesday as the snowpack will be stressed by the highest freezing level encountered yet this season.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    Skiers looking for dry snow on the shaded aspects should frequently test the surface layers. A shear persists down about 30 cm with preserved stellars and surface hoar. Recent winds and new snow have contributed to the growth of these slabs.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–3
    With significant heating in the forecast for Tuesday deep slabs may become active. Large loads such as falling cornices or smaller avalanches could trigger large avalanches on the March crusts or even the February facets.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–3
    Daily heating and the sun will create moist snow at low elevations and on solar aspects. As crusts break down Loose Moist or even Wet Slab avalanches will result. Cornices will also be affected by this heating and could trigger persistent slabs.

Weather Forecast

Freezing level rose to 2800m Monday. With a poor overnight recovery forecast, and more solar heating into Tuesday, the snowpack will be weakened further. Overnight rain with snow above 1800m and strong winds will add heat at low elevations and windloading above for Wed when more sun is expected. A better recovery is seen Wed Pm with more sun Thurs.

Snowpack Summary

Surface crusts on East through West aspects have formed with the daily heating pattern and rain below 1700m. Down 30 to 40cm on shaded aspects a shear persists on the 0325 interface. The strong March crusts are found down 70 to 100cm on all but North aspects above treeline and overlie the Feb facets that remain weak at about 1m above the ground.

Avalanche Summary

Widespread superficial loose moist activity has been seen over the last few days as a result of heating. On Sunday heating was strong enough that one of these triggered a 40 cm deep slab on an E aspect. Expect this activity to increase Tuesday. On shaded aspects and at higher elevations a few windslabs have been seen following modest new snow input

Confidence

Timing or intensity of solar radiation is uncertain

Régions couvertes