Avalanche forecast

South Coast

Apr 9 – 10, 2015Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Highlights

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

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Daytime warming and sunshine could weaken large overhanging cornices and cause them to fail. These are a hazard alone, but also a potential trigger for deeper weak layers.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    There are two persistent weak layers still present in the upper snowpack. These have not been reactive for a few days now, but intense spring sun , a wind slab avalanche,  or cornice fall could be enough to reawaken this problem.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Expect loose wet activity on steep sun-exposed slopes during the day.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Friday: Increasing cloud with snow beginning late in the day. 10 cm of snow expected overnight with the freezing level coming down to 1200m by morning. Winds forecast moderate to strong from the S-SW. Saturday: Cloudy with snow flurries. The freezing level continues downward to around 1200-1400 m and winds are moderate from the SW.Sunday:  Cloudy with flurries, freezing level around 1000m and winds light to moderate from the south.

Avalanche Summary

Moist loose avalanches have been reported on steep sun-exposed slopes, and one natural cornice fall (size 2) was reported earlier in the week, but didn't trigger a slab release on the slope below.

Snowpack Summary

On shady slopes, 15-25 cm of cold low-density snow sits on a strong and supportive rain crust that was buried last Saturday and extends as high as 2100m. Expect an ongoing melt-freeze cycle on sun-exposed slopes. 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 daytime warming and intense sunshine.

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