Avalanche Forecast

Issued: Apr 3rd, 2018 4:00PM

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

deryl kelly, Parks Canada

Jasper.

Good riding on dry snow for the time being. Persistent instabilities, will persist for the remainder of the season.

Summary

Weather Forecast

"La Nina" spring continuing. A slow shift into 'spring-like' weather for the Rockies. Gradually, the NW flow is being replaced with a western zonal flow. This will eventually push the arctic air out, but temperatures and freezing levels are not expected to rise above valley bottom before Friday. Light winds with a trace of precip for the region.

Snowpack Summary

A variety of slab conditions exist on most aspects at treeline and above. 10-20cm of recent storm snow has created a settled new wind slab. This slab can be 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

No new avalanches reported or observed.

Confidence

Due to the number of field observations

Problems

Wind Slabs

In most cases this interface presents as a manageable surface instability and is expected to go dormant pretty quickly. Pay close attention to any fellow travelers above and/or below you as enter fresh terrain.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2.5

Cornices

Cornices are growing with fresh snow additions. Several failures were noted, in most cases triggering a slab below.

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

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

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.

Avoid shallow snowpack areas where triggering is more likely.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2.5

Valid until: Apr 4th, 2018 4:00PM