Avalanche forecast

Sea To Sky

Feb 9 – 11, 2012Avalanche Canada
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Archived · expired 15 years ago

Avalanche danger

Sat
Sun
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Moderate SE winds have formed specific wind slabs in the immediate lee below ridgelines and behind terrain features.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–6
    Cornice fall may trigger slabs on the slopes below. Give cornices a wide berth when traveling on ridgetop, or on slopes below.

Confidence

Fair - Intensity of incoming weather is uncertain on Friday

Weather Forecast

Overnight Thursday: Snow amounts 5-10cms. Ridgetop winds 30-40km/hr from the SE. Friday: Snow amounts 2-5cm. Ridgetop winds 20km/hr from the South. Freezing levels near 1800m. Saturday/Sunday: A ridge will persist through the weekend. Bringing mainly cloudy skies, and accumulations 2-5cms. Freezing levels near 1100m accompanied by moderate SW winds.

Avalanche Summary

On Wednesday natural cornice fall occurred. This large trigger pulled out a size 3 slab avalanche from the slope below. The avalanche occurred on a North aspect @ 1800m. The crown depth was up to 1.5 m, running 800m. No new avalanche activity was reported on Thursday.

Snowpack Summary

Recently, dribs and drabs of snow has fallen on a variety of surface forms. The bond of this new snow will need to be monitored as incremental loading may occur over the next week. The new snow sits on a variety of old surface snow conditions. They consist mainly of crusts that have developed due to melt/freeze conditions, and direct solar impact on steep Southerly aspects. Northerly aspects still host dry, wintery snow. On exposed lee slopes in the alpine there are pencil-4 finger stiff wind slabs. Surface faceting is occurring on sheltered, shady aspects. While shallow, rocky slopes are faceting and weaker; posing a threat to deeper releases. Surface hoar growth is 5-10mm at treeline, and below treeline. These may be our next layers of concern once buried. The Feb 01 (120201) rain crust is down 10-40 cm up to about 2000 meters. The mid-January crust is down between 50-100 cm, and the mid December crust is buried down up to 200 cm. The average snowpack depth at 1650m is near 240cm.

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