Avalanche Forecast

Issued: Mar 31st, 2018 4:46PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs, Cornices and Persistent Slabs.

rupert wedgwood, Parks Canada

Jasper.

Good skiing in wind sheltered treeline locations.

Summary

Weather Forecast

Cooling temps overnight as the arctic air takes dominance. Light shifting winds from S to E will leave some good snow in sheltered treeline locations for Sunday. This will be topped up by snow flurries of up to 5cm under mostly cloudy skies. Freezing levels are expected to stay near valley bottom elevations.

Snowpack Summary

A variety of slab conditions exist on most aspects at treeline and above. 10-20cm of recent storm snow has created a soft storm slab. This storm slab is up to 30cm thick . Below this, older slabs up to 60cm thick sit on a sun-crust on solar aspects and facets on polar aspects. Below treeline the snow is shallow.

Avalanche Summary

Explosive work today in the Icefields area produced numerous soft slab up to size 2.5 from all aspects. Although mostly thin storm stabs some of these stepped down to the March 15th interface. Also noted at TL and above from the past 36hr numerous; point release from steep rocky terrain, cornice failures and slab releases up to size 2.5.

Confidence

Due to the number of field observations

Problems

Storm Slabs

Explosive work today produced numerous results on this storm slab interface. Typically 50m or less but with larger triggers up to 100m. It is expected this instability will settle out quickly as there is no significant sliding interface.

Be careful with wind loaded pockets while approaching and climbing ice routes.Use caution on open slopes and convex rolls

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Cornices

Cornices are growing with fresh snow additions. Several failures were noted from the past 36hrs triggering slabs below

Pay attention to overhead hazards like cornices which could easily trigger deep slabs.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2.5

Persistent Slabs

Wind slabs sit on a hard melt-freeze crust on solar aspects, and facets on polar aspects. Assess the bond at these interfaces carefully before committing to to a slope.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Avoid shallow snowpack areas where triggering is more likely.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Apr 1st, 2018 4:00PM