Avalanche forecast

South Columbia

Feb 16 – 17, 2016Avalanche Canada
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Avalanche danger

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

Check out our new blog post. There is some uncertainty when and if we will see the sun, and how much that will affect the recent storm snow.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Wind slabs may be touchy and easy to trigger in the alpine and at treeline. This problem may result in wide propagations on easterly aspects where the recent storm snow may not be well bonded to the old crust.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Warm temperatures and high freezing levels during the day may result in loose wet avalanches starting in steep terrain like rock bands and gully walls.

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Overcast on Wednesday with light snow, moderate southerly winds, and freezing levels rising from valley bottoms overnight to about 1400 metres during the day. Overcast with moderate snow (5-10 cm) on Thursday combined with moderate southwest wind and freezing levels rising from valley bottoms up to 1300 metres. On Friday, overcast with light snow, moderate southwest winds, and freezing levels rising up to 1400 metres.

Avalanche Summary

On Monday we had reports of natural wind slab and storm slab avalanches up to size 3.0 and accidentally triggered slab avalanches up to size 1.5. Evidence of a natural wind slab avalanche cycle to size 2.5 was observed at treeline and in the alpine on Sunday. Most of the natural activity is thought to have occurred in the height of Saturday night's storm, while wind slab avalanches to size 1.5 were ski cut during the day. Of note, there was a report of a skier-triggered wind slab avalanche in Rogers Pass. The size 2 avalanche failed on a cross-loaded feature at 2150m. Two people went for a ride in the avalanche, one of whom sustained injuries and was rescued by helicopter on Monday morning.

Snowpack Summary

15-20 cm of new snow combined with moderate southwest winds created new wind slabs in the alpine and at treeline by Tuesday morning. The new snow will overlie older wind slabs and settling storm snow from the past few days. About 40-60 cm below the surface, you'll likely find a melt freeze crust. This crust exists in most places except for higher elevation shaded terrain. The bond between the recent storm snow and the crust is variable across the region, east thru southeast aspects have been the most reactive over the past few days. Surface hoar buried in early January now lies up to 200cm below the surface and has become less of a concern. Possible triggers for this deep and destructive layer include a large cornice fall or significant warming.

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