Avalanche Forecast

Issued: Feb 25th, 2018 4:29PM

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.

garth lemke, Parks Canada

Jasper.

A firm slab, sitting over several persistent weak layers, can be found in isolated areas in the forecast region. Triggering it remains possible and would be a high consequence event.

Summary

Weather Forecast

Monday will be cloudy with sun and flurries, trace amounts of snow, and -14 with light gusting moderate West winds. Tuesday will be sunny periods and flurries, trace snow, -17 to -12 and light gusting strong West winds. Wednesday will be similar to Tuesday with lighter winds.

Snowpack Summary

Strong W and N winds have left wind slabs and wind effect in open areas. The upper snowpack has settled to form a cohesive stiff slab that is sitting on three persistent weak layers mid-pack (down 50 to 80cm) which can be found throughout the forecast region, and did produce many large avalanches during the Feb 8th cycle.

Avalanche Summary

Helicopter patrol down highway 93 noted no new avalanches and visibility was good. This past week there was minimal natural activity yet it is still prudent to treat slopes that did not avalanche in the Feb 8 cycle as being suspect.

Confidence

The weather pattern is stable

Problems

Persistent Slabs

A stiff slab 50 to 80cm thick, sits over sun Crusts (south and west aspects), Surface Hoar (at, and just above treeline) and weak Faceted Crystals (very developed in shallow snowpack features).

Use conservative route selection, stick to supported terrain features, avoid overhead hazards.Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3.5

Wind Slabs

Expect hardslabs in the alpine and a few softer slabs at treeline. The cold has kept these in check and helped them settle over the last few days but some caution is still warranted.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.The best powder will be found in sheltered locations at or below treeline.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 26th, 2018 4:00PM