Avalanche forecast

South Rockies

Mar 30 – 31, 2015Avalanche Canada
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Avalanche danger

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

Warmth is the main driver of avalanche hazard at the moment. Minimize your exposure to large slopes if the snowpack is becoming moist or wet.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Watch for isolated wind slabs immediately below ridge crest.  Wind slabs in motion may entrain loose snow gaining considerable mass as they move downhill.  Large visor like cornices that overhang many ridge-tops are likely prone to failure.

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    As the snowpack is subjected to ongoing significant warmth, the bond that loose snow, fresh wind slabs and small storm slabs have with the underlying crust should rapidly decay. Potentially large wet avalanches remain possible Tuesday.

Avalanche Summary

On Monday our field team was in the Crown Mountain area where they noticed a few large slab avalanches on an extreme E/NE face that were likely triggered by cornice fall.  On Saturday in the neighboring Lizard Range a size 2.5 avalanche that was likely triggered by cornice fall was observed, but the bulk of the observed activity was limited to minor sluffing and small loose wet avalanches.

Weather Forecast

Tuesday: Freezing level starting around 2500m, lowering to 1500m by days end. Strong SW winds at treeline, Extreme SW winds at ridgetop. No significant precipitation expected.Wednesday: Freezing level hovering around 1500m. Partly cloudy skies all day. Moderate W winds at treeline, Strong W winds at treeline. No significant precipitation.Thursday: Freezing level holding around 1500m. Light variable winds at treeline, light W winds at ridgetop. No significant precipitation expected.

Confidence

Poor

Snowpack Summary

Sustained warm temperatures are helping to rapidly settle the snowpack at and below treeline. Ongoing SW winds have likely left lingering wind slabs on north through east facing features. The mid-March rain crust is down 30-60cm and has shown a good bond with snow above. Old persistent weak layers are still intact in the mid and lower snowpack. There is potential for these layers to wake up with sustained warming and/or significant rain. Recent cornice growth has been reported and these cornices may become fragile with daytime warming.

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