Avalanche forecast

South Coast

Mar 22 – 23, 2014Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Hazards may be higher than forecast on solar aspects in the afternoon. Pay close attention to danger from cornices.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    Continued small amounts of storm snow have produced wind slabs at tree line and above. Steep solar aspects may become active when the sun comes out on the recent storm snow. A cornice failure could produce a large destructive avalanche.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3–6
    The deep persistent layers seem to be dormant for the time being, but may be reactive with a large load, ( a cornice failure )or a rapid warming event.

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Synopsis: An arctic high pressure ridge in the interior of BC will cool things down before the next Pacific frontal wave arrives on Monday..Tonight: Cloudy with a trace of precipitation, freezing level around 200 metres, winds light, from the north west.Sunday: Sunny with some cloudy periods, no precipitation in the forecast, freezing level around 400 metres, light ridge top winds from the north west.Monday: Cloudy with flurries, freezing level around 400 metres, winds light to moderate from the north.Tuesday: Cloudy with snow, 10 to 15 cm in the forecast, freezing level at 400 metres, winds light, south west.

Avalanche Summary

No reports of avalanche activity from yesterday. Steep south aspects may be of concern in the afternoon. Conditions seem to be improving, but It may be too early to be stepping up to bigger objectives.

Snowpack Summary

Between 35and 60 cm of 7-day storm snow has increased the slab sitting on the persistent weak layers. Wind slabs formed during the storms are reported to be bonding well to the storm slab. The two persistent weak layers that remain a concern are:The March weak layer. A combination of hard wind-scoured slab surfaces in exposed terrain, facets and/or surface hoar in sheltered and north aspects, and sun crust on steep solar aspects and is generally widespread throughout the forecast region. This layer is now down between 70 and 80cm from the surface.A late January/early February crust/facet/surface hoar combo that is still showing up in snowpack tests with hard shear tests, now down 150 to 250cm from the surface. Recent warming temperatures will be good for bonding above and below this layer, but a sudden increase in load, a cornice failure, or a big rain event could "wake up" this layer and result in large avalanches. There are also basal facets at the bottom of the snowpack from cold clear weather in early December, but for the most part these have not been a concern, however, recently, a few large avalanches have stepped down to the basal facets and the ground.

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