Avalanche Forecast

Issued: Apr 2nd, 2017 4:00PM

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

mark herbison, Parks Canada

Jasper.

Weaknesses deep the in the snowpack can be triggered from shallow areas or by large triggers. Daytime and solar heating will weaken cornices, avoid traveling under or to close to them.

Summary

Weather Forecast

Light flurries Monday afternoon with a mix of sun and cloud, light winds from the NW. Freezing level up to 1600m with an alpine high of -5. Clear skies and warming temps for Tuesday and Wednesday.

Snowpack Summary

12cm new snow in the past 36hrs, winds gusting to 60km/hr from SW building slab. The mid-pack is bridging the basal weakness, which consists of weak facets, depth hoar and the Nov rain crust. Isothermal conditions below tree-line on solar aspects.

Avalanche Summary

Recent cornice and windslab failures have triggered the deep persistent slab creating large full path avalanches that are traveling into valley bottoms. Loose wet avalanches have been occurring on steeper south and west aspect below tree-line.

Confidence

Timing or intensity of solar radiation is uncertain on Tuesday

Problems

Wind Slabs

New windslab formed by recent SW winds could be reactive and if triggered, could step down to the deep persistent slab.

Use caution in lee areas. New snowfall mixed with wind loading will created slabs.Be careful with wind loaded pockets while approaching and climbing ice routes.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Cornices

Cornice failure is hard to predict but is more likely with inputs like solar radiation and wind-loading.

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, South.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

This problem is unlikely to disappear. It can be triggered by large loads like cornice fall or windslab failure. Human triggering is most likely from shallow spots or on steep unsupported slopes.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.Be cautious in shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Apr 3rd, 2017 4:00PM