Avalanche Forecast

Issued: Apr 1st, 2017 4:08PM

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

a.l. horton, Parks Canada

Jasper.

Resist the temptation to travel on big slopes that have not yet avalanched. Weaknesses deep in the snowpack can be triggered from shallow snowpack areas and have the potential to run full path.

Summary

Weather Forecast

10 cm of snow expected Saturday night with easing SW winds.Â Freezing level falling to 1300 m.Â Cloudy spring-like weather Sunday and Monday.Â Sun and warm temperatures are predicting starting on Tuesday.

Snowpack Summary

Recent large cornices failures have triggered the deep persistent slab creating size 3 avalanches. Previous S-M SW winds formed windslab on lee aspects. A thick and strengthening mid-pack is bridging basal weakness. The lower snowpack is weak with depth hoar, Nov rain crust and basal facets. 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 well into historic run-outs. 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.

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

Elevations: Alpine.

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.

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.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 2nd, 2017 4:00PM