Avalanche forecast

Northwest Coastal

Jan 30 – 31, 2013Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–6
    Over the past week up to meter of new snow has fallen on a crust/facet/surface hoar interface. This interface may be found most reactive in sheltered areas over convex rolls or steep terrain. Dig down and see how reactive it is in your riding area.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–5
    New snow will continue to build storm slabs. Strong shifting winds will build touchy wind slabs that are likely found behind terrain breaks such as ridges and ribs and on lee slopes. Natural avalanches are possible and rider triggers are likely.

Confidence

Fair - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

Thursday: Storm snow 10-25 cm with heaviest amounts West of Terrace. Ridgetop winds blowing 30-60 km/hr from the West. Alpine temperatures near -4 and freezing levels rising to 600 m.Friday: Continued cloudy skies and snow amounts near 5 cm. Ridgetop winds light from the SW. Alpine temperatures near -2 with freezing levels rising to 900 m.Saturday: Moderate-heavy precipitation. Ridgetop winds light from the South. Alpine temperatures -3.0 with freezing levels near 800 m.

Avalanche Summary

Two slab avalanches size 2.5 naturals occurred out of steep wind loaded terrain on an East aspects. Numerous size 2.0 loose and moist avalanches occurred naturally on steeper solar aspects in the afternoon.

Snowpack Summary

The region has received close to a meter of recent storm snow. This new snow has been building storm and wind slabs over a variety of old snow surfaces (old wind slabs, melt-freeze crusts, surface hoar and scoured slopes). Much of the recent snow is being drifted into big wind slabs by strong NW wind.  Reports generally indicate that the bulk of this storm snow seems to be settling quickly, which is a good. However, with a continued stormy pattern I would wait out the storms and watch how the snowpack adapts.Lingering beneath the new snow sits two persistent weaknesses comprising of surface hoar/ facets and a melt-freeze crust. I suggest you keep these on your radar in regards to reactivity and sensitivity with the additional loading pattern. If reactive, with up to a meter of new snow regionally,  these buried weaknesses may be susceptible to producing large avalanches. The mid and lower snowpack is generally well settled and strong, although basal facets remain a concern in the northern part of the region.

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