Avalanche Forecast

Issued: Feb 23rd, 2019 4:00PM

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

jasper snow safety, Parks Canada

Jasper.

Fresh windslabs have formed on a variety of aspects on the 93N, while surface snow remains unaffected by wind in the Marmot / Whistler / Tonquin Creek region.

Summary

Weather Forecast

Sunday will be sun with clouds, no precipitation, Treeline Low -21, High -16, and light ridge winds. Monday will be similar, but with alpine temperatures dropping and winds rising toward moderate through the afternoon. Little change for Tuesday, except the coldest morning of the lot! Mountain weather forecast available at Avalanche Canada.

Snowpack Summary

Fresh windslabs have formed in exposed terrain, lee to SW then N winds. Remnants of a surface hoar layer (Jan 18) down 40cm could be reactive in isolated areas treeline and below. A strong midpack exists in thick snowpack areas, but is weaker in thinner snow-pack zones over weak basal depth hoar, consistently giving hard, sudden results in tests.

Avalanche Summary

No field patrol Saturday, nothing new reported. Thursdays field team (Nigel Pass area, Columbia Icefields Region) observed two avalanches triggered by small cornice failures; one triggered a size 1.5 deep persistent slab (steep, unsupported N aspect, at 2700m), the other triggered only a loose dry avalanche in a large planar slope.

Confidence

Wind effect is extremely variable

Problems

Wind Slabs

Strong SW winds blew for 24 hours yesterday in the columbia Icefields area, and have now switched to steady moderate from N. In the southern areas of the bulletin region, expect a cornucopia of windslabs on a variety of aspects.

Be careful with wind loaded pockets while approaching and climbing ice routes.Variable winds have created pockets of wind slab on all aspects.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Deep Persistent Slabs

Although natural deep persistent slab avalanches have been few and far between lately, they are still possible in isolated places. Steep, unsupported, and thin/variable depth are factors to be wary of.

Be cautious in shallow snowpack areas where triggering is more likely.Minimize exposure to terrain traps where the consequences of an avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Loose Dry

This problem is probably isolated to terrain where surface snow doesn't show signs of previous wind affect : all elevations at the north end of the bulletin region, but only lower elevations in the Columbia Icefields region

Minimize exposure to terrain traps where the consequences of an avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 1.5

Valid until: Feb 24th, 2019 4:00PM