Avalanche Forecast

Issued: Apr 9th, 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.

a.l. horton, Parks Canada

Jasper.

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

Summary

Weather Forecast

Melt-freeze cycle in the valley bottoms. Light winds and cool temps keeping the surface snow dry above tree-line. Pulses of precipitation (rain below tree-line and snow above) into the week. Starting to see strong diurnal spring temperature cycle developing.

Snowpack Summary

Good skiing above 2000m. Icefields has10cm of settled storm snow. This rests 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. Consistent melt-freeze cycle below tree line. Surface crusts are breaking down by mid morning.

Avalanche Summary

A couple sz 3 avalanches in steep un skiable terrain NE alpine where cornice failure has triggered deep persistent slab.

Confidence

Timing or intensity of solar radiation is uncertain on Tuesday

Problems

Deep Persistent Slabs

This problem will persist. Activity has subsided but, need to keep this on your radar. It can be triggered by large loads such as cornice failures or human triggered from shallow spots or 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

Unlikely - Possible

Expected Size

2 - 4

Cornices

Cornice failure is hard to predict. Some very large cornices are out there so wise to give them a wide berth.

Give cornices a wide berth when travelling on or below ridges.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 possible as melt freeze breaks down by late morning.

Minimize exposure to steep slopes on warm or sunny days.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Apr 10th, 2017 4:00PM