Avalanche forecast

Kootenay Boundary

Apr 19 – 20, 2018Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

High overnight freezing levels combined with continued warm temperatures and sunny skies on Friday will increase the likelihood of loose, wet avalanche activity.  These releases can start small and gain mass quickly becoming a big problem.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5
    Sunny skies and warming air temperatures will rapidly weaken the snow surface and increase the likelihood of triggering loose wet avalanches. Expect natural avalanches on steep slopes, particularly south aspects under sunny skies.

Confidence

-

Weather Forecast

TONIGHT: Mostly clear. Ridge wind light, southwest. Alpine temperature near +1. Freezing level 2200 m.FRIDAY: Mostly sunny. Increasing cloud and rain overnight. Precipitation up to 5 mm. Ridge wind light southwest. Alpine temperature near +2. Freezing level 2200 m.SATURDAY: Cloudy, flurries. Accumulation 5-10 cm. Ridge wind moderate to strong, southwest. Alpine temperature near -2. Freezing level 1700 m.SUNDAY: Mix of sun and cloud. Ridge wind light, northwest. Alpine temperature near 0. Freezing level 2000 m.

Avalanche Summary

Wednesday numerous natural loose, wet avalanches (size 1-1.5) were observed on solar (southeast, south, and west) aspects in the southeastern part of the region.On Tuesday there was a report of a skier-triggered storm slab size 1.5 on a north aspect at treeline north of Rossland that failed on a crust. Read MIN report here.On Monday, loose wet avalanches were triggered naturally and by explosives. They were large (size 2 to 2.5) and on all aspects between 1700 m and 2100 m.

Snowpack Summary

Snow and warm temperatures on Thursday have likely moistened the 35 to 60 cm of storm snow that fell earlier in the week.  This snow sits on a melt-freeze crust that formed following rain and warm temperatures on Sunday. Numerous other melt-freeze crusts exist in the upper snowpack from rain, sun, and warming during the spring season. The mid and lower snowpack are generally well-settled and strong.At lower elevations below treeline, a spring snowpack exists.

Regions covered