Avalanche forecast

South Coast

Feb 13, 2018Avalanche Canada
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Archived · expired 9 years ago

Avalanche danger

Wed
Thu
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Highlights

Maintain elevated caution around areas where wind loading has occurred. Small avalanches can have big consequences around cliffs and other terrain traps.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5
    Wind slabs may have a poor bond to the underlying crust and be reactive at upper alpine elevations. Recent shifting winds may have formed new slabs on a wide range of aspects. Loose dry avalanches are possible from steep alpine terrain features.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–2
    Large cornices have formed and may remain fragile. Cornices are inherently unstable, unpredictable, and demand respect. Give them a wide berth from above and below.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Tuesday: Cloudy with flurries beginning late in the day and bringing 10-15 cm of new snow by Wednesday morning. Moderate to strong southwest winds. Freezing level dropping to 500 metres as the temperature inversion breaks down. Alpine high temperatures of -4.Wednesday: A mix of sun and cloud. Light north winds. Freezing level to 700 metres with alpine high temperatures of -2.Thursday: Mainly cloudy with flurries increasing over the day and bringing approximately 15 cm of new snow by Friday morning. Light southwest winds increasing over the day and overnight. Freezing level to 600 metres with alpine temperatures of -3.

Avalanche Summary

On Saturday, a cornice collapse was the likely cause of a size 2 avalanche on a north facing slope near the West Lion. See here for images and more details. Pockets of thin wind slab may exist in wind-loaded areas in the high alpine and may be sensitive to human triggers.

Snowpack Summary

Rain at the end of the week saturated snow surfaces and only higher alpine elevations were lucky enough to receive a light cover of new snow. With the arrival of cold temperatures, the upper snowpack has locked up as a firm crust. Where new snow exists above the crust, it has been redistributed by recent strong southwest winds. The average snowpack depth at treeline is 300 cm of well settled snow with no significant layers of concern.

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