Avalanche Forecast

Issued: Mar 31st, 2017 7:03PM

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

rupert wedgwood, Parks Canada

Jasper.

Solar radiation will rapidly and dramatically increase the avalanche danger at all elevations if it occurs . Pay close attention to freezing levels.

Summary

Weather Forecast

Snow at the icefields over Sat and Sun, total 15cm. Winds Mod SW alpine highs -4. FzL 1,800m

Snowpack Summary

Temp surface crusts below 1,700m on all aspects, extending to treeline on Solar facing slopes. Below the crust at lower elevations the snowpack is turning isothermal. Thin soft wind slabs at ridge features which stiffen and thicken with elevation. The midpack is consolidated and providing bridging strength over a weak and faceted snowpack base.

Avalanche Summary

Several slab avalanches size 2-3 from steep easterly facing alpine terrain. These were likely triggered by cornice failures and stepped down to basal layers running into the valley bottom. Explosive work at lower elevations produced several class 2 moist snow avalanches.

Confidence

Freezing levels are uncertain on Sunday

Problems

Cornices

Large cornices on ridge top lee features continue to build with strong SW winds. Their sheer mass is a problem. Recent alpine releases have resulted in large slab avalanches.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.Give cornices a wide berth when travelling on or below ridges.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Deep Persistent Slabs

The deep persistent slab can be triggered by travelers from shallow or weak locations or naturally from large loads such as cornice failure or windslab avalanches.

Avoid shallow snowpack areas where triggering is more likely.Avoid paths that have not avalanched recently.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Wind Slabs

Strong SW winds in the alpine have produced wind slabs from recent snow fall. These will be most reactive at upper elevations near ridge features. If triggered they may step down to deep basal weakness.

Use caution on open slopes and convex rolls Avoid lee and cross-loaded terrain near ridge crests.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Apr 1st, 2017 4:00PM