Avalanche forecast

Northwest Coastal

Apr 13 – 14, 2015Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
4 · High
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Localized solar radiation, snow amounts and wind values may be higher than forecast. Avoid avalanche terrain during periods of heavy loading by snow, rain and wind.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    Additional storm snow loading on the mid- March persistent weak layer could bring it back to life. Smaller storm slab avalanches may step down to this layer, initiating large, destructive avalanches.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–3
    Storm slabs are touchy especially where they sit on a buried  facet, surface hoar and/ or crust interface. Strong winds have built wind slabs in lee terrain in the alpine and at treeline. Use caution and watch for reverse loaded slopes.

Confidence

Fair - Due to the number of field observations

Weather Forecast

Winter continues in the North as another intense storm moves onto the coast tonight resulting in very strong winds and moderate precipitation amounts. Very unstable air will result in unsettled conditions on Tuesday where localized heavy precipitation is possible (10-30 mm) accompanied by strong west winds and freezing levels near 1000 m. On Wednesday, precipitation amounts could see up to another 25 mm, freezing levels and winds consistent with Tuesday. There will be a lull in the weather pattern Thursday before things redevelop on Friday as another storm tracks across northern BC.

Avalanche Summary

Recent explosive control has produced loose dry avalanches up to size 1.0. With continued snow, rain, and strong winds natural avalanche activity will occur on Tuesday, touchy wind slab and storm slab avalanches size 2 or greater will likely be the primary concern.

Snowpack Summary

At upper elevations 25- 40 cm of recent low density storm snow has been redistributed by strong south west winds into wind slabs on lee slopes. With recent changing winds from the NE, you may find some reverse loaded pockets in unsuspecting places. The lack of bond between the new wind slabs and storm slabs over the older snow surfaces buried on April 9 th (surface hoar, crusts and facets) are the primary concerns. The March 25th surface hoar / crust layer is reportedly unreactive, however; with the new load of wind and snow this should remain on your radar as it may re-awaken, initiating very-large and destructive avalanches.

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