Avalanche forecast

Kootenay Boundary

Mar 19 – 20, 2014Avalanche Canada
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Avalanche danger

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

Watch the temperature and solar warming! Heat and cornices are two great ways to shake-up the snowpack over the next couple of days.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Wintery conditions are more likely found in north parts of the region where the mountains are higher and there was less rain. Treeline Hazard may be closer to Considerable in these parts and the South Columbia bulletin is worth reading.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3–5
    The deeply buried weak layers still show "sudden" results in snowpack tests. Triggers for large avalanches on these layers include cornice falls, solar warming, or hitting the wrong place in a thin snowpack area.

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Thursday: Snow should end overnight Wednesday with storm totals around 10 - 15 cm, having fallen with a moderate SW or W wind. Mixed sun and clouds, dry, temperatures below zero near treeline, except freezing level like to climb with solar radiation. Light to moderate NW wind.Friday: Very similar to Thursday except the wind should stay light from the NW.Saturday: A weak system expected to move in backing the wind to the S, increasing the clouds, light precipitation, and slightly warmer.

Avalanche Summary

From the reports we've received, avalanche activity has slowed right down with colder temperatures and the end of precipitation. Only reports from professionals were of snowballing and thin slabs on steep solar aspects.

Snowpack Summary

25 to 40 cm of snow from the previous storm was blown by strong winds into deeper deposits in lee terrain; the variable and shifting direction of those winds mean a complex pattern of lee and cross-loaded slopes. Rain at lower elevations saturated the snowpack. Colder, below freezing temperatures is turning the wet snow into a frozen crust; however, fresh snow above the rain-soaked layer is like a blanket of insulation and delays the freezing. These recent accumulations overlie crusts on sun-exposed slopes (SE - W aspects) and surface hoar in shaded terrain. Deeper in the snowpack is a facet/crust persistent weakness buried at the beginning of February, now down 70 to 160cm, has been highly variable in terms of reactivity but still shows 'sudden' results in snowpack tests. These layers are still difficult to trust and any avalanche at these deeper, persistent interfaces would be large and destructive.,Weak basal facets exist in some areas, but without a large load on the right piece of terrain, triggering is unlikely.

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