Avalanche forecast

Lizard-Flathead

Mar 24 – 25, 2018Avalanche Canada
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Archived · expired 9 years ago

Avalanche danger

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

Up to 35 cm of recent storm snow is being redistributed by the predominant southwest wind will likely build thicker, reactive slabs on leeward slopes. If the sun pokes out it may initiate a natural avalanche cycle in the recent storm snow.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–2
    Changing winds from East-West continue to be strong, redistributing the recent storm snow onto most aspects. Wind slabs will likely be reactive to skier/rider triggers. Loose dry avalanches may occur from steeper terrain features.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2.5
    Large looming cornices exist across ridgelines. Cornices are unpredictable and demand respect. They're more likely to fail during wind events or when the sun comes out.

Confidence

Moderate - Wind speed and direction is uncertain

Weather Forecast

Sunday: Mix of sun and cloud with possible snow amounts 2-5 cm. Ridgetop wind strong from the southwest. Alpine temperatures near -4 and freezing levels 1300 m. Monday: Cloudy with sunny periods. Ridgetop wind strong from the southwest. Alpine temperatures near -4 and freezing levels 1300 m. Tuesday: A mix of sun and cloud. Ridgetop winds strong from the southwest. Freezing levels 1300 m.

Avalanche Summary

Cornice control work showed numerous size 1-2 avalanches on north through southeast ridgelines. above 1900m. The cornice failures produced mostly loose dry avalanches from the slopes below with a few smaller slabs only releasing in the storm snow. On Friday, numerous natural storm slab avalanches were reported from North aspects above 1700 m. Periods of sunshine forecast for Sunday could trigger a round of natural slab avalanches and loose dry/wet avalanches.

Snowpack Summary

Up to 40 cm of recent storm snow will initially have a poor bond to the plethora of old snow surfaces including a melt-freeze crust on sunny aspects and all aspects below 1600 m, surface hoar on north aspects above 1600 m. Wind slabs are building on most aspects due to the changing winds and overhanging cornices exist along ridgelines. Deeper in the snowpack, the mid-December and late-November weak layers are composed of crusts and sugary facets, which are down 150-300 cm. These layers are currently dormant.

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