Bulletin d’avalanche

Northwest Inland

Jan 22 – 23, 2012Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Tue
Wed
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–4
    Stiff windslabs have developed during the strong northeast outflow winds. New soft windslabs continue to develop due to southwest winds and new snow.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Dry light snow falling at the beginning of the storm may become heavier as the temperatures rise, and develop a storm slab that may not bond to the old cold surface. If temperatures stay cool, expect sluffing in the new snow.

Confidence

Good - -1

Weather Forecast

Light flurries on Sunday are expected to become moderate snowfall overnight into Monday morning, bringing 10-15 cm to the mountains near Terrace, and 5-10 cm more inland near Smithers. Moderate south winds on Sunday night are forecast to swing to the southeast by Monday morning and then shift to southwest and build to about 35 km/hr at ridgetops by Monday afternoon. This is a relatively fast moving low pressure between two week ridges of high pressure. The next big event is forecast for Tuesday morning, when freezing levels are expected to begin to rise and heavy precipitation combined with strong southwest winds will move into the region from the Pacific. Freezing levels are expected to briefly rise as high as 1500 metres by Tuesday afternoon. Temperatures should cool and snow should continue on Wednesday.

Avalanche Summary

No new reports of avalanches observed.

Snowpack Summary

The new storm has brought about 15 cm to the Interior. The snowpack in the Seaton Basin is reported to be 250 cm at 1650 metres, with a moderate shear down 40 cm on a facet layer. The snowpack depth in the Smithers-Hankin area is about 250-275 cm at the upper extent of the treeline elevation band. Some surface facetting has been observed above treeline, and some surface hoar observed below treeline. Very strong northeast outflow winds have scoured north and east aspects and reduced previous cornice growth. The snow has been transported into stiff windslabs on south through west aspects. These windslabs should be stiff enough in most areas that the forecast southerly winds will not be able to re-distribute the snow. The mid-december crust has been observed to have bonded to the mid-pack in most areas, but may be found to have become facetted in areas with a shallow snowpack. The mid-pack is considered to be strong and well settled in most areas. No basal weak layers of concern have been reported.

Régions couvertes