Avalanche forecast

South Columbia

Apr 5 – 6, 2016Avalanche Canada
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Avalanche danger

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

Wednesday is your best bet if you're craving fresh snow, but watch for fresh touchy wind slabs in exposed lee terrain. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    New snow and strong westerly winds have combined to build fresh wind slabs in exposed leeward terrain. Expect any new snow to sluff off easily if the sun pokes out in the afternoon. 

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–5
    Cornices are large and weak and could pop off naturally as temperatures rise and the sunshine returns. 

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–6
    The chance of slabs failing on buried persistent weaknesses will be on the rise this week. Extra caution is necessary if the snow becomes wet and slushy.

Confidence

Moderate

Weather Forecast

WEDNESDAY: Cloudy with light snow to start (5-10 cm), and possible sunny breaks in the afternoon. The freezing climbs to 2300-2400 m late in the day and winds are moderate from the West. THURSDAY: Mainly sunny. The freezing level shoots up to 3400 m. Winds should ease to light and variable. FRIDAY: Mainly sunny. The freezing level stays above 3000 m and winds should remain light.

Avalanche Summary

Cooler temperatures and cloud cover helped reduce avalanche activity on Monday. I suspect isolated wind slabs and fresh loose wet slides were the main concerns on Tuesday. As we move back to warm and sunny weather I would expect renewed loose wet activity on solar aspects, natural cornice falls, and isolated large persistent and wet slab avalanches.

Snowpack Summary

Around 20 cm of new snow fell on Monday (above 1500 m) with cooling temperatures and moderate or strong W-NW winds. Fresh wind slabs are likely in exposed lee and cross-loaded terrain. A new melt-freeze crust may have formed below the fresh snow, which should help temporarily stabilize the snowpack. The March 22nd rain crust is buried 50-60 cm deep up to around 2000 m. We could see more activity on this layer when temperatures soar later in the week. The late February persistent weak layer is now down 60 to 120 cm below the surface. While it may be a concern in isolated terrain, it would probably take a large trigger like a cornice fall or surface avalanche in motion to provoke it.

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