Avalanche forecast

Northwest Coastal

Mar 4 – 5, 2017Avalanche Canada
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Avalanche danger

Sun
Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Storm slabs are very reactive to human triggers. Conservative terrain selection is crucial.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Fresh storm slabs are reactive and have a poor bond to the old snow surfaces. Deeper deposits of wind slabs may also exist on leeward slopes and behind terrain features.

Confidence

High - Due to the quality of field observations

Weather Forecast

SUNDAY: Light flurries confined to coastal areas, 20-30 km/h south winds, alpine temperatures around -12 C.MONDAY: Cloudy with scattered flurries and 3-5 cm of new snow, 30-50 km/h south winds, alpine temperatures around -12 C.TUESDAY: Stormy with 15-20 cm of new snow, 30-50 km/h south winds, alpine temperatures around -12 C.

Avalanche Summary

On Friday, storms slabs were very reactive to human triggers producing numerous size 1-1.5 avalanches and widespread whumpfing and cracking in flat terrain. Explosive control resulted in numerous size 2-2.5 slab avalanches. A widespread natural cycle occurred during the peak of the storm with up to size 2.5 slabs on a variety of elevations and aspects. Conditions will remain touchy as the recent storm snow settles and stiffens.

Snowpack Summary

60-80 cm of recent storm snow has buried a variety of old snow surfaces including surface hoar, facets, crusts, stiff wind slabs and a melt-freeze crust below 1600 m. The storm snow has been very reactive on this interface including widespread whumpfing and cracking in flat terrain. Below this interface the snowpack is generally settled and strong with the exception in shallow snowpack areas around Bear Pass and Ningunsaw where basal facets remain an ongoing concern.

Regions covered