Avalanche Forecast

Issued: Apr 23rd, 2018 4:23PM

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

jasper snow safety, Parks Canada

Jasper.

Solar triggered avalanches and cornice failures will increase in frequency the next few days as each day will be warmer than the previous. Temperatures expected to spike Wednesday and Thursday.

Summary

Weather Forecast

Tuesday will be sun and cloud, no snow, high of 3 C, light winds, and 2600m or higher freezing level. Wednesday will be similar but warmer and with a slightly higher freezing level. Thursday will be sunny and very warm with freezing level up to 3600m and 10 C temperatures.

Snowpack Summary

Sun or temperature crusts extend to treeline and into the alpine on southerly slopes. Persistent slabs can be found on most aspects at treeline and above. These have been reactive to large triggers like cornice failures. Below 1,900m the snowpack is going isothermal on a daily basis.

Avalanche Summary

Monday there was a report of a size 2 above upper weeping wall stopped at the trees. Another size 2 was noted on the Churchill slide path. Things are waking up with the rising temperatures. Sunday size 2 slab avalanche occurred on the E slopes of Lectern, initiating in the alpine and running to treeline. Loose wet activity is also increasing.

Confidence

Problems

Loose Wet

The next few nights and days will be progressively warmer increasing the probability of loose wet avalanches. Start and end early plus be vigilant of overhead hazard as these avalanches have been gaining mass and running far.

Use extra caution on solar slopes or if the snow is moist or wet.If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

Triggering this slab would have serious consequences. Cornice failures are acting as triggers.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1.5 - 3

Cornices

Rising temperatures are causing cornices to fall triggering slopes below. Give them a wide berth.

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

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Likely

Expected Size

1.5 - 3

Valid until: Apr 24th, 2018 4:00PM