Avalanche forecast

Sea To Sky

Apr 5 – 6, 2017Avalanche Canada
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Avalanche danger

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

A series of pacific frontal systems impacting the coast in the coming days will elevate the avalanche danger.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3
    Large cornices may become weak with daytime warming or during periods of stormy weather.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    The combination of new snow, moderate to strong southerly winds and warm temperatures have created reactive storm slabs. These are expected to especially touchy in the lee of exposed terrain features.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Friday

Weather Forecast

THURSDAY: Flurries, accumulation 5-10cm / Moderate south wind / Alpine temperature -2 / Freezing level 1500mFRIDAY: Snow, accumulation 20-25cm / Moderate to strong south wind / Alpine temperature -1 / Freezing level 1500mSATURDAY: Flurries, accumulation 5-10cm / Moderate to strong southwest wind / Alpine temperature -4 / Freezing level 1200m

Avalanche Summary

Reports from Wednesday include explosives triggered storm slabs running to size 2, 30cm deep. On Monday a few natural cornice releases to size 2.5 were observed running to the bottom of their run outs entraining loose snow only. On Sunday, a natural cornice release triggered a size 3 slab avalanche which release down 60 cm and ran to valley bottom. On Thursday, expect newly formed wind and storm slabs to be reactive to human triggering. These slabs are expected to be particularly touchy where they overlie a melt-freeze crust.

Snowpack Summary

20-30cm of new snow at upper elevations sits on widespread melt-freeze crusts on all aspects and elevations except for high elevation north facing terrain. On all aspects below 2000 m and higher on sun exposed slopes, there may be multiple crust layers in the upper snowpack. Moderate to strong alpine wind from the south will have redistributed this new snow and formed additional wind slabs in the alpine and at tree line which may overlie a crust. Large overhanging cornices exist primarily on north aspects in the alpine.

Regions covered