Avalanche forecast

South Coast

Apr 10 – 11, 2015Avalanche Canada
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Avalanche danger

Sun
Mon
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

The hazard may go higher than forecast if precipitation amounts are greater than expected.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    Incoming storms with strong wind will build wind slabs in lee exposed slopes

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    New snow load may tip the balance on existing, large cornice features.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    This slab overlying the March 25 persistent weak layer is still on the radar with professionals in the area.

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

A series of Pacific cold fronts will move into the area late today ( Friday ) and leave 5 to 10 cm of snow at upper elevations., Winds will be moderate to strong from the south west. Freezing levels should drop to 1000m for the next few days, with daytime heating raising the freezing level to 1500m for Sunday and around 1700m for Monday afternoon.  Monday may see another 5  cm of snow at upper elevations.

Avalanche Summary

Little in the way of avalanche activity from yesterday.  Moist loose avalanches had been reported earlier in the week, but with falling temperatures this activity has gone dormant. Expect wind slab activity with new loading and strong winds.

Snowpack Summary

5 to 15cm of incoming precipitation will fall on a variety of crusts and old surfaces including surface hoar and facets  that formed in sheltered locations during the recent clear weather. Moderate to strong south west winds will redistribute the storm snow into wind slabs on the lee sides of ridge tops. A facet/crust layer that was buried in mid-March is now approximately 50-100 cm down. Recently it was found down 55 cm near the Duffey Lake Road, and produced moderate sudden results. This remains a concern in the region because of it's potential for very large avalanches. Cornices are now large and mature and may collapse with increased loading, possibly triggering the deeply buried weak layer.

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