Avalanche Forecast

Issued: Feb 26th, 2018 4:09PM

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

conrad janzen, Parks Canada

Banff Yoho Kootenay.

We have not seen much recent avalanche activity, but keep in mind the potential for power sluffing of the surface facets in steep terrain, and the existence of hard wind slabs at higher elevations.

Summary

Weather Forecast

The forecast is for periods of snow starting on Monday night and continued flurries through Tuesday and Wednesday with total accumulations of up to 10 cm. Temperatures should stay in the -8 to -15 range at treeline and winds will be moderate to strong out of the West, possibly easing off on Wednesday.

Snowpack Summary

A few cm of new snow Sunday night. Wind effect in open areas at treeline and above with faceted surface snow below treeline. Three mid-pack weak layers of surface hoar and/or facets are down 100-130cm and gaining strength, but are worth keeping in mind on bigger slopes. Thin snowpack areas are facetting and weakening with the cold temperatures.

Avalanche Summary

Reports of thin wind slabs triggered by ski cutting and explosives in lee areas at the local ski resorts. We had a rescue response to a skier triggered wind slab in a steep couloir near Taylor Lake on Sunday. Reports of skier triggered sluffs resulting in loose dry avalanches running to mid path in steep terrain in the Kootenay area.

Confidence

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

Problems

Wind Slabs

Hard wind slabs exist in lee areas in the alpine. While they may not be very thick or particularly touchy, they certainly have the potential to carry you into an undesirable location (cliffs/terrain traps) if triggered in steep terrain.

Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

A strong upper snowpack overlies three weak layers in the mid snowpack. All are a mix of sun crust, surface hoar and facets depending on location. We have not had any recent avalanche activity on these layers but keep them in mind in large terrain.

Ride large slopes one at a time and spot your partners from safe locations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Feb 27th, 2018 4:00PM