Avalanche Forecast

Issued: Apr 10th, 2017 4:00PM

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

garth lemke, Parks Canada

Jasper.

The slopes look inviting but Jasper Forecasters are still leery of big alpine slopes that have not seen ski traffic or previous avalanche activity.

Summary

Weather Forecast

Tuesday and Wednesday nights will dip to -9 and warm up to -3 during the day. Winds may shift Easterly Tuesday night bringing 5-10cm of new snow by Wednesday morning.

Snowpack Summary

Good skiing above 2000m. Icefields has 10cm of soft snow on a solid mid-pack which bridges the weak base above 2000m. The base is a combination of weak facets and depth hoar mixed around a Nov rain crust. A consistent melt-freeze cycle is occurring below tree line. Surface crusts are breaking down by mid morning.

Avalanche Summary

No patrol Monday. On Sunday a couple sz 3 avalanches in steep un-skiable terrain NE alpine where cornice failure has triggered deep persistent slab.

Confidence

Problems

Deep Persistent Slabs

The deep instability could be triggered by large loads such as a cornice failure or a surface avalanche. 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

Unlikely - Possible

Expected Size

2 - 4

Cornices

Cornice failure is hard to predict but likelihood increases with sun, warm temperatures, and wind-loading. There are some very large cornices out there. Wise to give them a wide berth.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Loose Wet

Isothermal conditions are possible as crusts break down by late morning. Gauge the extent of the overnight freeze relative to how quick it will move into being reactive.

Minimize exposure to steep slopes on warm or sunny days.If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Apr 11th, 2017 4:00PM