Avalanche forecast

Kootenay Boundary

Jan 8 – 9, 2014Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    Loading in the coming days could awaken the persistent weak layers that have been unreactive lately. If they reach their tipping point, large avalanches could occur.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    A storm slab will start building with the accumulation of the snow forecasted. Touchy windslabs will also form with the moderate W-SW winds. Watch for sluffing in steeper sheltered terrain.

Confidence

Fair - Intensity of incoming weather systems is uncertain on Saturday

Weather Forecast

Tonight and Thursday: Precipitation intensity should pick up tonight, slow down during the day tomorrow and pick up again Thursday night with the arrival of another system . Around 15-20 mm. in water equivalent is forecasted for that period. Strong winds from the SW are forecasted for the Western part of the region and  light to moderate for the rest of the region. Freezing levels should remain at the surface.Friday: Light precipitation, most of it should fall late Friday night. Moderate W winds for the day. Freezing levels are forecasted to rise close to 1000 m during the day.Saturday: More of the same due to the zonal flow directing multiple systems inside the province. However this system looks stronger and could leave bigger amounts of precipitation than the previous systems. Temperature are expected to be warmer at first and winds to be strong.

Avalanche Summary

No new avalanches were reported yesterday.

Snowpack Summary

The light to moderate amounts of snow forecasted before the weekend and moderate winds from the W-SW will most likely create new windslabs below ridgetop in the alpine and cover older windslabs from previous wind event. Sluffing will also be possible in steep terrain where this new snow will be sitting on a surface hoar layer in sheltered areas below treeline. Note that this new surface hoar layer is sitting on a suncrust on S facing aspects in some areas. The persistent weak layers (PWL) are definitely a concern to avalanche professionals since they keep giving sudden planar results and show good propagation potential when tested. The end of November facet/crust or surface hoar layer down 80 cm (or 40 cm where snowpack is very thin) and the depth hoar or basal facetting are the most worrisome layers. Presently, they do not seem reactive to skier triggering but this situation could change with additional loading from the forecasted snow and wind. 

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