Avalanche forecast

Banff Yoho Kootenay

Feb 4 – 5, 2019Parks Canada
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Archived · expired 8 years ago

Avalanche danger

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

Increased reactivity of the Jan 17 surface hoar/crust layer is due to recent loading of storm snow. Distribution is spotty, so dig down to verify if this layer is present in your local area.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5
    Wind was observed redistributing the recent storm snow in the alpine and creating fresh windslabs in lee areas. These slabs could be up to 70cm deep. For clarity, the storm slab problem has transitioned into the windslab problem.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    The Jan 17 layer is a combination of Surface Hoar and/or a melt freeze crust. Since the recent storm, it has become reactive to skier traffic and can generally be found down 50cm. Dig down, look and test this layer at tree line and below.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–3
    The new snow load may start waking up the deep persistent facet weakness down 80-160 cm. This is of greatest concern in shallow snowpack areas where the basal facets are weakest.

Weather Forecast

Thankfully, today is forecasted to be the coldest day. Temperatures will climb back to a somewhat reasonable level by tomorrow to about the -18 range in the valley. A clearing trend will ensue, and the wind will drop back to light from the West. No snow is forecasted for a while.

Snowpack Summary

30-45cm of recent storm snow is being redistributed into windslabs above treeline. Up to 65cm sits over the Jan.17 surface hoar which has been found up to 2300m. In shallower areas weak facets and depth hoar exist below the Dec 10 interface. In deeper snowpack this basal weaknesses is less pronounced

Avalanche Summary

No avalanches reported or observed today, however yesterday there were two skier accidental avalanches size 1.5. One was on Vermillion Peak (reported on the MIN) the other was at Bow Summit. Both were suspected to have slid on the Jan 17 Surface Hoar. No injuries or lost gear in either slide.

Confidence

Due to the number of field observations on Sunday

Regions covered