Avalanche Forecast

Issued: Apr 28th, 2018 4:00PM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Loose Wet, Persistent Slabs and Cornices.

jasper snow safety, Parks Canada

Jasper.

Summary

Weather Forecast

Saturday night will be wet flurries, 6cm of snow, -3 degrees, light North wind, and 1800m freezing level. There may be a weak temperature inversion Saturday night and Sunday. Sunday will be flurries, 8cm of snow, high of -3, light E winds, and 1900m freezing level. Monday will be sun and cloud, no precipitation, and 2300m freezing level.

Snowpack Summary

Moist/wet snow extends to treeline on all but the most Northerly slopes. Persistent slabs are on most aspects at treeline and above. They have been reactive to triggers like cornice falling and larger loose wet avalanches. Below 2200m the snowpack is isothermal as there has been no overnight freeze except for Northerly aspects.

Avalanche Summary

The spring avalanche cycle is in full swing with temperatures reaching 17 degrees. Large destructive avalanche are running from all elevations and going far into the valley bottom.

Confidence

Problems

Loose Wet

With most of the snowpack below 1,900m being isothermal expect these avalanches to start early on solar slopes at all elevations. Incoming precipitation may be rain adding to this problem.

If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 3

Persistent Slabs

With warm temperatures and solar radiation these events are occurring. Cornices falling are acting as triggers. These events can run far into the valley below

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1.5 - 3.5

Cornices

All cornices should be considered unstable. Give them a wide berth and don't end up below them.

Pay attention to overhead hazards like cornices which could easily trigger persistent slabs.Avoid steep slopes below cornices.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Very Likely

Expected Size

1.5 - 3

Valid until: Apr 29th, 2018 4:00PM