Avalanche forecast

Kootenay Boundary

Feb 14 – 15, 2016Avalanche Canada
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Avalanche danger

Tue
Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Local danger will depend on how much new snow falls on Monday. Expect danger to be considerable or higher if more than 40 cm of storm snow overlies the recently buried crust. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    Heavy loading, warming, and sunny periods could reactivate buried surface hoar. This is more likely in drier areas where surface hoar is found in the upper metre of the snowpack.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–4
    Storm slabs continue to build. The recent snow sits on a melt-freeze crust or surface hoar and could be sensitive to human triggering on Monday.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Loose wet slides are likely on solar aspects if the sun pokes out, and all steep slopes below treeline if we see the forecast warming and rain late on Monday.

Confidence

Moderate - Forecast snowfall amounts are uncertain on Monday

Weather Forecast

Monday: Periods of snow with possible sunny breaks. Kootenay Pass could be in the bullseye with as much as 30-40 cm, while other areas should expect 10-20 cm. The freezing level is around 1500 m spiking to 1800 m late in the day. Winds are moderate to strong from the SW.  Tuesday: Periods of snow (5-10 cm) with possible sunny breaks. The freezing level is around 1800 m and winds ease to light. Wednesday: Showers or flurries. The freezing level is around 1800-2000 m and winds are light.

Avalanche Summary

One size 2 accidentally triggered slab avalanche was reported in the Northern Rossland Range on Saturday. This avalanche was about 40 cm deep and was triggered on a NE aspect. One person was partially buried but escaped unharmed. Reports from other parts of the region included a few size 1 skier-controlled wind slabs and some small loose wet sluffs during a brief sunny break on Saturday.

Snowpack Summary

10-25 cm of new snow sits on a supportive crust at and below treeline, a breakable crust on south-facing slopes in the alpine, buried surface hoar in sheltered terrain, or wind affected surfaces. Moderate southerly winds may have created fresh dense wind slabs on exposed leeward slopes. An older buried crust can be found down 40cm extending well up into the alpine. At the same depth (around 40 cm), a buried surface hoar layer may be reactive on northerly aspects in the Rossland Range. Below this, a thick slab rests on a layer of surface hoar that was buried earlier in January. This layer is 80-130 cm deep and poses a low probability/ high consequence threat. It should remain on your radar, especially during periods of warming or rapid loading.

Regions covered