Avalanche Forecast

Issued: Nov 29th, 2018 4:41PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is below threshold. Known problems include Wind Slabs and Deep Persistent Slabs.

Ruari MacFarlane, Parks Canada

Jasper.

Strong winds have raked the Alpine, with hard wind affected snow the norm. Pockets of softer snow are available near Treeline. Hazard will decrease daily with a dry, cooling trend.

Summary

Weather Forecast

Friday: Valley fog clearing. Calm winds. Treeline High -8, no precipitation.Saturday: Cloudy. Light NE winds. Treeline high -9, flurries (trace amounts).On Sunday, a brief NE upslope further ramps up cloud cover and drags down temps, but promises little snowfall.Click here for the Avalanche Canada mountain weather forecast.

Snowpack Summary

Previous Strong SW winds left the Alpine heavily wind affected. The October 25 crust, found towards the bottom of the snowpack, has not produced recent avalanches in the region. This crust is predominantly in deep snowpack areas, such as N & E facing lee features. Facets and Depth Hoar below this layer have given broken results in snowpack tests.

Avalanche Summary

A road patrol of the Icefields Parkway in good visibility revealed only one avalanche, a Large (size 2) natural in the Alpine (2400m) on a N aspect. This was likely a wind slab, possibly cornice triggered, occurring during strong winds on Wednesday.

Confidence

Due to the number of field observations

Problems

Wind Slabs

Strong to extreme winds early-mid week have left widely scoured surfaces with pockets of hard windslab. These are suspected to be stubborn to unreactive to human triggering, but if triggered may propagate wider than expected.

Watch for areas of hard wind slab in steep alpine features.Convex features and steep unsupported slopes will be most prone to triggering.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Deep Persistent Slabs

Although it seems currently dormant, it would be wise to assess the strength of the interfaces above & below the October 25 crust before entering committing lines. This layer exists in most skiable slopes. See forecast details for more info.

Watch for whumpfing, hollow sounds, and shooting cracks.Ride slopes one at a time and spot for your partners from safe locations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Valid until: Nov 30th, 2018 4:00PM