Avalanche forecast

Banff Yoho Kootenay

Apr 6 – 7, 2018Parks Canada
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Avalanche danger

Sun
Mon
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

A skier triggered avalanche yesterday afternoon highlights the serious nature of the March 15 persistent slab problem. Watch for increasing avalanche hazard through the weekend with incoming new snow.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–2
    Expect to encounter smaller windslabs in the alpine. They range from 20-40cm thick and have been decreasing in sensitivity over the last couple of days. Watch for the incoming storm to establish new slabs Saturday and Sunday.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–2.5
    Dig down to test the bond to the Mar 15 crust, bearing in mind that the bond can vary significantly with subtle changes in slope aspect and steepness. Forecasters suspect this problem is developing with  faceting on the crust due to recent cold temps

Weather Forecast

Continued flurries overnight Friday with more significant snowfall expected on to start mid afternoon Saturday with and increase in temperatures. Expect both the new snow and the increasing temperatures to lead to an increase in the avalanche hazard. Further increases in temperature can be seen in long term forecasts, a significant change to watch.

Snowpack Summary

Trace amounts of new snow in the past 18 hours. Last week's storm brought 15-40cm with moderate S and W winds creating wind slabs in the alpine. The March 15 suncrust is down 25-50cm on south-east through west aspects and has been sensitive to skier triggering over the last few days.

Avalanche Summary

Visitor Safety responded to Sentinel Pass for a skier accidental avalanche reported by the involved party via In-reach at approx 1700hrs April 5. Avalanche failed on March 15 crust persistent layer that has been sensitive to skier triggering for a couple of weeks ... 20-50cm deep at 2575m ,SE aspect, 200mx200m. Impressive save by party members.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Saturday

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