Avalanche Forecast

Issued: Apr 22nd, 2017 4:00PM

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

garth lemke, Parks Canada

Jasper.

Travel early and be off slopes by mid-day.

Summary

Weather Forecast

Next few days will be slightly cooler than previous with some Arctic air, lower freezing levels, and light E winds. The sky will be mix sun and cloud with light flurries or rain in the valley. Accumulations will be minimal.

Snowpack Summary

10-20 cm snow Thursday night has settled into place. The upper snowpack is moist or wet by the afternoon depending on aspect and elevation. The mid-pack is solid and bridging the weak base. The bottom 30cm of the snowpack consists of weak facets and depth hoar mixed around the Nov rain crust. Below 1500m there is no snow.

Avalanche Summary

No field patrol today and no public reports. Maligne Road was closed Friday afternoon due to increasing loose wet avalanche hazard on a very warm sunny afternoon.

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Loose Wet

Warm temperatures and direct solar radiation influence the distribution and magnitude. Freezing overnight temperatures decrease the danger in the morning until it warms up increasing the hazard. Most widespread on solar facing slopes.

Start and finish early before the surface crusts melt.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

The deep instability could be triggered by a cornice failure. It is well bridged by a solid mid-pack; however, consider this problem becoming more active particularly on South aspects as the day warms up or the sun comes out.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Cornices

Cornice failures are still being noted periodically on West aspects 2500-2800m. Give them a wide berth as their failure is hard to predict but increases with sun, warmth, wind-loading, or new snow.

Give cornices a wide berth when travelling on or below ridges.Avoid travel on slopes that are exposed to cornices overhead.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Apr 23rd, 2017 4:00PM