Avalanche forecast

Lizard-Flathead

Mar 7, 2017Avalanche Canada
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Archived · expired 10 years ago

Avalanche danger

Tue
Wed
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

A week of heavy snowfall and strong winds has left large storm slabs and cornices primed for human triggering. Avoid overhead hazards and stick to mellow terrain.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Always look up and avoid exposure to overhead cornices.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Storm slabs remain likely for rider triggering, especially on leeward slopes and behind terrain features that are wind loaded.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

We're looking at occasional flurries and cool temperatures throughout the forecast period. TUESDAY: Flurries with up to 5 cm of new snow, 20-40 km/h southeast winds, alpine temperatures around -9 C. WEDNESDAY: Flurries with 5-10 cm of new snow, 20-30 km/h east winds, alpine temperatures around -8 C. THURSDAY: Cloudy with scattered flurries and up to 3-5 cm of new snow, 30-50 km/h east winds, alpine temperatures around -12 C.

Avalanche Summary

Cornices are large and remain easy to trigger. See here for a great MIN post from Sunday illustrating just how surprising the results can be.Several size 1.5 to 3 natural and explosives triggered avalanches were reported on Saturday. Aspects were east through northwest, from 1500m to ridgetop.A widespread natural avalanche cycle occurred on Friday night, with many size 2-3 cornice triggered avalanches on north and east aspects. Natural activity is expected to taper off, but storm slabs will remain possible for human triggering.

Snowpack Summary

Another 10-20 cm of snow fell on Sunday into Monday, bringing the weekly total to over 115 cm. Strong southwest winds have extensively redistributed the snow and formed large brittle cornices.The new snow came in "upside down" (heavier, denser snow over lighter snow) and is rapidly settling into a slab which sits over a variety of old surfaces including surface hoar, facets, stiff wind slabs, sun crusts, and a rain crust below 1900 m.Isolated basal weaknesses may still exist in shallow snowpack areas and appear to isolated to north-northeast aspects in the alpine.

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