Avalanche Forecast

Issued: Apr 8th, 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.

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

Be watchful for wind slabs in immediate lee areas at high elevations. Depending on local new snow amounts and wind velocity the slabs could be touchy with wide propagations.

Summary

Weather Forecast

The weather is slowly transitioning to a diurnal cycle from the unseasonably cool spring temperatures. Expect above zero temps in the valleys bottoms (~5 degrees) during the warmest parts of the upcoming days. Monday will bring cloudy skies and very light accumulations of snow (~4cm). Wind will pick up to the moderate range from the W-SW.

Snowpack Summary

Up to 15cm in the past 24 hours that has been redistributed by moderate wind from the SW has produced wind slabs in lee areas in the alpine. The March 15 suncrust is down 30-50cm on south-east through west aspects and has been sensitive to skier triggering over the last few days. No major concerns exist below the Mar 15 crust at this time.

Avalanche Summary

A size 2 windslab was observed on a NE aspect at 2600m near Lake Louise today. No other avalanches were observed or reported.

Confidence

Due to the number of field observations 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

Recent new snow and wind have created new soft wind slabs in immediate lees in the alpine.

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 - 2

Valid until: Apr 9th, 2018 4:00PM