Avalanche Forecast

Issued: Apr 4th, 2017 4:00PM

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

mark herbison, Parks Canada

Jasper.

Good skiing can be found in sheltered areas between 1900-2400m.Below tree line hazard will be low in the morning, but rising freezing level and solar heating will increase the hazard throughout the day.

Summary

Weather Forecast

Light flurries, 25-40km/hr SW winds with alpine high of -2 for Wednesday. Freezing levels rising to 2100m and forecasted to stay above 1800m until Friday. By the end of the week we might see up to 15cm of new snow at higher elevations.

Snowpack Summary

Good skiing between 1900-2400m in sheltered areas. Windslab along lee ridge-lines and cross-loaded gully features from SW winds. Mid-pack bridging basal weakness. Entire lower snowpack is weak with a combination of facets, Nov rain crust and depth hoar. Below tree line a supportive 20cm melt freeze crust sits above a weak facet layer to ground.

Avalanche Summary

No new avalanche observations on Tuesday. Previous cornice and windslab failures have triggered the deep persistent slab resulting large full path avalanches. Loose wet avalanches have previously occurred on steep south and west aspect below tree-line.

Confidence

Due to the quality of field observations on Tuesday

Problems

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.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 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

Loose Wet

Prolonged solar radiation and rising freezing levels with weaken the snowpack on South and West aspects, especially around steep and rocky areas.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 5th, 2017 4:00PM