Avalanche forecast

Banff Yoho Kootenay

Apr 6 – 7, 2013Parks Canada
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Avalanche danger

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

One more day of minimal overnight recovery of lower elevation crusts.  Monday and Tuesday we will start to return to regular spring conditions.  SH

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Storm slabs will heal with lowered freezing levels, but are still triggerable, especially where they overly harder crusts. See avalanche discussion.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    Below treeline expect near isothermal conditions with little freeze.  At treeline and above, natural loose wet avalanches will occur if the sun comes out and the day heats up.

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    The highest likelihood for deep wet slabs is from daytime warming on solar aspects,  especially from thin areas where slabs overly facets or depth hoar. 

Weather Forecast

Freezing levels to valley bottom Sunday morning, but expect only weak overnight recovery of crusts below treeline as most areas will be under cloud cover.  Freezing levels to 2000m in the afternoon. Expect only light precipitation Sunday.  Monday and Tuesday we should start to see good overnight crust recovery.

Snowpack Summary

10-20cm of new, dense snow in the alpine over the last 48 hours sits over crusts on most aspects except true N. Rain below treeline. Bow summit plot at 2000m today saw mainly isothermal snowpack with little freeze. Hard compression results down 60cm on facets. In that area E of the divide there are still depth hoar and facet layers near the ground.

Avalanche Summary

One size 2 in the alpine on a NE aspect looked to have occurred within the last 24 hours. It appeared to be 60 cm deep but visibility was poor. Failure plane possibly an ice crust formed on March 14. One skier triggered size 2 storm slab on a N aspect in the alpine reported in the Sunshine back country in steep terrain.

Confidence

Freezing levels are uncertain on Sunday

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