Avalanche forecast

Kootenay Boundary

Dec 5 – 6, 2015Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

If the region receives more than 20cm of snow Saturday night and Sunday, the danger will probably rise to HIGH at all elevations Sunday. Please share your observations via the Mountain Information Network. (MIN)

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    Ongoing snowfall should continue to energize the storm slab problem.  Savvy folks will choose terrain that provides lots of simple, well supported options.  I would not be surprised to see large human triggered avalanches in more challenging terrain.

Confidence

Low - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Strong southwesterly flow is expected to continue to drive moist and progressively warmer systems into the Kootenay Boundary. The dynamic nature of the current pattern makes it very difficult to pin down exact timing and corresponding precipitation amounts. As a result the ranges of expected precipitation are quite wide. SATURDAY NIGHT: Freezing level around 1000m, 1 to 15cm of snow possible accompanied by strong southerly winds. SUNDAY: Freezing level starting at 1000m rising to 1500m during the day. 1 to 12cm possible. Continued moderate/strong south/southwest winds expected. SUNDAY NIGHT: 5 to 20cm of snowfall. Freezing level at 1500m. Strong southerly winds. MONDAY: Freezing level climbing to around 2000m. Continued strong southerly winds. 10 to 30 cm of snow possible at upper elevations. TUESDAY: Potential for lots of moisture, but its hard to say how much this far in advance. The freezing level could go as high as 2500m. For a more comprehensive mountain weather forecast visit: avalanche.ca/weather

Avalanche Summary

We're receiving limited reports from the region and visibility has been poor. Recent observations suggest that the storm snow is becoming reactive as a soft slab, at least on convex features. No further details available.

Snowpack Summary

Up to 50 cm of storm snow now rests on a variety of old snow surfaces including stubborn wind slabs, crusts at upper elevations (especially on southerly aspects), loose faceted snow and surface hoar in sheltered areas. In some parts of the region a thick hard crust is reported to exist between 30 and 60 cm below the surface. For the time being, this hard crust is likely adding significant strength to the snowpack. That said, the combination of facets and surface hoar overlying a hard crust could become a reactive weak layer as more and more weight is added to it. There is also a thick crust from early-November deeper in the snowpack. The limited observations we have suggest that this crust is well bonded, but more data is needed before we write it off.

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