Avalanche Forecast

Issued: Apr 9th, 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.

conrad janzen, Parks Canada

Banff Yoho Kootenay.

Start early to take advantage of good travel conditions and cool temperatures on Tuesday morning. We expect the hazard will rise later in the day as things warm up and the precipitation arrives.

Summary

Weather Forecast

Tuesday will start out as a mix of sun and cloud with below freezing temperatures overnight helping with travel conditions. Some precipitation is expected to arrive Tuesday afternoon with up to 5-10 cm accompanied by strong West winds and freezing levels up to 2300m. Cooler temps and slightly drier conditions with some cloud is expected Wednesday.

Snowpack Summary

Moderate west winds over the past 24 hrs have created wind effect in open areas, and wind slabs in lee areas in the alpine, On solar aspects the March 15 sun crust is down 25-50 cm and has been sensitive to skier triggering over the last week. A temperature crust is present on all aspects below 2000m and higher on solar aspects.

Avalanche Summary

Some loose dry sluffing in the alpine due to strong wind gusts on Monday, as well as thin touchy wind slabs in immediate lee areas at local ski hills. Explosive control at Sunshine produced one size 2 wind slab. On Sunday a size 2 wind slab was observed on a NE aspect at 2600m near Lake Louise and some loose wet sluffing out of steep solar terrain.

Confidence

Timing of incoming weather systems is uncertain on Thursday

Problems

Persistent Slabs

Dig down to find and test the bond of the surface snow with the Mar 15 crust down 25-50 cm on steep solar aspects, bearing in mind that the bond can vary significantly with subtle changes in slope aspect, steepness or warming temperatures.

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 moderate West winds have created wind slabs in immediate lees areas of the alpine that can be triggered by skiers in some locations. This problem may increase later in the day on Tuesday as more snow arrives.

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 10th, 2018 4:00PM