Avalanche forecast

Kootenay Boundary

Jan 18 – 19, 2016Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Reports of whumpfing indicate a weak layer buried at the beginning of January may still be sensitive to light loads. Choose conservative terrain and watch for clues of instability.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Recently formed wind slabs are likely gaining strength, but may still be sensitive to light loads in unsupported lee terrain.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    Recent storm accumulations overlie a weak layer of surface hoar. Touchy conditions are expected in areas where the recent storm snow has settled into a cohesive slab.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Expect a mix of sun and cloud with isolated flurries on Tuesday and Wednesday. Ridgetop winds should be light to moderate from the southwest on Tuesday switching to light and northwesterly on Wednesday. A Pacific system will move into the region on Thursday bringing steady snowfall and strong southwest winds. Freezing levels should sit at or near valley bottom for the forecast period.

Avalanche Summary

Over the weekend we had limited observations of new avalanches. With the forecast static weather pattern I expect a drop in natural avalanche activity; however, human triggered persistent slab avalanches remain a concern in many areas.

Snowpack Summary

10-15 cm of new snow and moderate southerly winds have likely created fresh wind slabs in high elevation lee terrain. 35-60 cm below the surface you'll find a weak layer of well-developed surface hoar and a hard crust on steep solar aspects. Ongoing Mountain Information Network reports of whumpfing and shooting cracks show this layer is still sensitive to light loads. I would anticipate increased reactivity at this interface in areas where the overlying slab is deep and has gained cohesion through wind pressing, warming, and/or settlement. The mid and lower snowpack are generally well settled and strong.

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