Avalanche forecast

Banff Yoho Kootenay

Dec 17 – 18, 2019Parks Canada
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Archived · expired 7 years ago

Avalanche danger

Wed
Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low

Highlights

Increased wind and small amounts of new snow are creating new reactive wind-slabs at ridge top.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–1.5

    Overnight wind transport has created thin wind slabs predominantly on East aspects directly below ridge top. Pay attention to wind values and new snow amounts that contribute to this problem over the next 24 hours.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    The recent snow sits over weak facet and crust layers. As time goes on the chance of triggering is becoming less likely, but there is lots of uncertainty as to where you could trigger an avalanche and what it will take to get it moving.

Weather Forecast

Seasonal temps (-5 in the valley, -10 at the ridge) for the next few days. Light snow is expected totalling 10cm by Thursday midday. Ridgetop wind is expected to be in the strong to extreme range from the W-SW on Tuesday afternoon. Some more significant snow is expected on the weekend, but the outlook is still uncertain.

Snowpack Summary

Reactive, thin (~10cm) new windslabs are being created by increased west wind. Beneath the recent 40-60 cm of storm snow, the snowpack structure is generally weak, consisting of facets and depth hoar. The Nov crust is present up to 2500m and ~30 cm up from ground. Snowpack depths at treeline range from 80-160 cm.

Avalanche Summary

Small windslabs (size 1) were reported near Mt Ogden today. They likely occurred within the last 24 hours. Additionally, a small wind slab was triggered by 2 ice climbers on the half way ledge on Bourgeau Left today.

Confidence

Wind effect is extremely variable on Tuesday

Regions covered