Lawinenlagebericht

Northwest Coastal

Dec 18 – 19, 2011Avalanche Canada
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Archiviert · abgelaufen 15 years ago

Lawinengefahr

Tue
Wed
Hochgebirge
4 · Gross
Waldgrenze
4 · Gross
Unterhalb
4 · Gross
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Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely
    Größe
    1–5
    With forecast weather large wind slabs will form on cross-loaded and lee slopes. Due to high winds, loading may occur low on the slope or in other unsuspecting locations. They will be touchy and destructive in many parts of the region.

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely
    Größe
    1–4
    Forecast wind and snow will create storm slabs at all elevations. They will be touchy and destructive; especially in areas with a weak buried surface hoar/crust/facet interface. Storm slabs can run fast and be destructive.

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Monday

Weather Forecast

On monday an intense frontal system is forecast for the region. Snowfall amounts are in the 30-60cm range for many parts of the region. Expect strong to extreme wind values and freezing levels between 500-1000m.On tuesday expect light to moderate snowfall with light westerly winds in the morning with clearing late in the day. Forecast freezing levels at about 400m.Clearing is forecast for wednesday with light to moderate southwest winds and freezing levels at surface.

Avalanche Summary

Numerous size 2 naturals were observed in steep terrain on all aspects in the Bear Pass area on saturday. Near Shames recent size 2 naturals were observed as were significant whumphing and cracking.With the intense wind and snow forecast for monday we can expect another significant natural avalanche cycle.

Snowpack Summary

The southern part of the region has received up to 70-90cm of snow over the past week (Kasiks, Terrace areas) and less snowfall to the north. This has formed storm slabs at all elevations. This new snow has been blown around by strong southwest winds creating new wind slabs on lee slopes. Buried beneath the new snow sits a variety of weak snow surfaces (melt-freeze crust, surface hoar above the crust and facetted snow below the crust) that are a result of rain and then the early December dry spell. This crust is up to 20cm in thickness and extends up to alpine elevations in the south, and around 1000m in the north. The surface hoar growing on the crust was sized up to 10mm. Widespread avalanche activity has occurred throughout many parts of the region and the surface hoar may have been cleaned-out as a result. In more snow-deprived parts of the region, more incremental loading is taking place and these weak layers are gradually reaching their threshold.The mid and lower snowpack are well settled and strong.On monday an intense frontal system is forecast for the region (see weather forecast). Expect significant further wind and storm slab development.

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