Avalanche Forecast

Issued: Apr 7th, 2017 4:00PM

The alpine rating is considerable, 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.

15cm of warm snow Thursday to Friday enhanced ski quality. Evaluate snow and terrain carefully as human triggering remains possible. Forecasters still do not have much faith in this snowpack.

Summary

Weather Forecast

For the Icefields, Friday night will have a little warm snow. Saturday - Sunday's freezing level will drop to 1500m and then 1100m on Monday. Temperatures will hover around -3 to -8 and light snow Saturday to Monday.

Snowpack Summary

Good skiing between 1900-2400m in sheltered areas. Icefields received 15cm of warm snow. This rests on a solid mid-pack that is bridging a weak base. The base is a combination of weak facets and depth hoar mixed around a Nov rain crust. Below tree line is a supportive 20cm melt freeze crust sitting above a weak facet layer to ground.

Avalanche Summary

No Patrol or public reports on Thursday or Friday. Wednesday's helicopter flight from Jasper to Sunwapta Resort to Maligne lake reported no new avalanches noted and visibility was good. Tuesday's patrol at Bald Hills also did not note any new avalanches. Despite natural activity subsiding forecasters have low confidence in the deep basal weakness.

Confidence

Due to the number of field observations on Saturday

Problems

Deep Persistent Slabs

This problem will persist. Activity has subsided but with all the variables beyond our control, 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

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

Possible

Expected Size

2 - 3

Loose Wet

This problem will be reduced next few days as temperatures get cooler ; however, light rain may continue on Saturday. Keep this on your radar. Caution is warranted for ice climbers in gullies.

Make your travel plans to take advantage of overnight freezing.Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 8th, 2017 4:00PM