Avalanche forecast

Banff Yoho Kootenay

Apr 16 – 17, 2014Parks Canada
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Avalanche danger

Fri
Sat
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Highlights

A large avalanche (skier remote) was triggered on Mt. Whymper yesterday. This was regarded as an anomaly. Deep persistent slab avalanches are still possible. Continue to make judicious terrain choices as the spring conditions set in.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Hot temperatures will be the incentive for this problem to become more active. A quick blast of solar energy on south aspects at low elevations will be all it takes to get the snow moving.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–3
    As yesterdays avalanche on Mt Whymper demonstrates, large avalanches are still possible. While this is not a widespread problem, deep basal layers are still susceptible to human triggering.

Weather Forecast

Cloudy skies and light precip is forecasted for the region. Generally, there will not be enough accumulation to alter the danger rating. The first increase in temperature is forecasted on Saturday. If this comes to fruition, expect a major cycle with large avalanches running on the basal facets.

Snowpack Summary

A supportive melt-freeze crust exists on all aspects to 1900m and higher on south and west aspects. Dry snow exists on N/NE aspects above this. The snowpack is well settled with no surface instabilities. The deep persistent weak layers are dormant, but may awaken if it warms up. As demonstrated yesterday on Mt. Whymper, (see avalanche table).

Avalanche Summary

Forecasters were very surprised yesterday after hearing a report of a size 3.5 skier remote avalanche on Mt. Whymper. The group heard a whumph and 30 seconds later the slide released taking out the whole slope the party had just climbed up from 70m away. Dimensions: 400m wide x 100cm deep x 1000m long. Reminder, nothing is certain. Picture

Confidence

Regions covered