Avalanche Forecast

Issued: Apr 2nd, 2018 4:00PM

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

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

Slow improvement in conditions. However, use caution on solar aspects where a windslab overlies the Mar 15 crust. Dig down to test the snow before committing to your line.

Summary

Weather Forecast

Unseasonably cold temperatures remain (below zero) in the Valley bottoms for a few days yet. Until Thursday the ridge temperature will stay in the -15 range. Cloud cover and light amounts of precip are expected to track through the region starting early Tuesday (~5cm). The wind will increase to the moderate range from the SW on Tues.

Snowpack Summary

Last weeks storm brought 15-40cm with moderate S and W winds creating wind slabs in the alpine and into exposed areas at treeline. 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. The mid- pack land basal layers have been dormant for the past while.

Avalanche Summary

A skier remote size 1.5 was observed just outside the Lake Louise ski area boundary on an East aspect this afternoon. It appeared to be a windslab that ran on the Mar 15th crust.

Confidence

Due to the number of field observations on Monday

Problems

Wind Slabs

Expect to encounter windslabs on all aspects at treeline and higher. They range from 20 to 40cm thick. On solar aspects, where the Mar 15 crust exists, potential remains for these wind slabs to be touchier than polar aspects.

Watch for surface cracking and stiffer surface layers of snow.Use caution in lee areas. Recent wind loading have created wind slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Dig down to test the bond between the recent storm snow and the Mar 15 crust. While activity has tapered, forecasters do not have the confidence to remove this problem. Forecasters also suspect faceting on the Mar 15 crust due to recent cold temps.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Apr 3rd, 2018 4:00PM