Avalanche Forecast

Issued: Apr 7th, 2018 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Persistent Slabs and Wind Slabs.

stephen holeczi, Parks Canada

Banff Yoho Kootenay.

5-10cm in the forecast for Sunday. It should stay cloudy but watch for local solar input which will increase the danger. We haven't had the big spring warmup yet but early next week could see a spike in temperatures.

Summary

Weather Forecast

Cloudy with light snow overnight into Sunday. We should see 5-10cm with West winds dipping into the moderate range. The East slopes could see some decent warming Monday and Tuesday with increased solar input.

Snowpack Summary

Trace amounts of new snow in the past 24 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

In the last few days, there was a skier accidental avalanche at Sentinel Pass, and another 2.5 avalanche on the S side of Isolated Col in Little Yoho. Both avalanches were in the alpine on solar aspects, and failed on the March 15 crust persistent layer that has been sensitive to skier triggering for a couple of weeks.

Confidence

Timing or intensity of solar radiation is uncertain on Sunday

Problems

Persistent Slabs

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.

Be cautious with convexities and steep slopes on solar aspects.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Wind Slabs

Expect to encounter smaller wind slabs in the alpine. They range from 20-40cm thick and have been decreasing in sensitivity over the last couple of days. Incoming snow and wind could see new small wind slabs near ridge top.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Apr 8th, 2018 4:00PM