Avalanche Forecast

Issued: Mar 28th, 2013 7:38PM

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

a.l. horton, Parks Canada

Jasper.

Spring conditions exist. Now is the time to start early and finish early in the afternoon before the snowpack heats ups and starts moving.

Summary

Weather Forecast

The freezing level is expected to go above 2000m with light westerlies winds and mostly sunny skies.

Snowpack Summary

A 15 to 20 cm melt freeze crust on solar aspects below treeline appears to be maintaining its strength until late in the afternoon. Isothermal conditions are beginning on shallow south facing slopes at treeline. The alpine snowpack is relatively stable where it is thicker especially on polar aspects.

Avalanche Summary

Numerous wet loose avalanches were observed along the Parkway on all solar aspects from treeline to valley bottom. Slides ranged from 0.5 to large 2 in size.

Confidence

Timing or intensity of solar radiation is uncertain on Friday

Problems

Loose Wet

Without a good overnight freeze, this problem will wake up by early afternoon.

Start and finish early before the surface crusts melt.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

Large triggers such as cornice fall has triggered this weakness. We expect to see large avalanches on steep slopes with warm temperatures rising into the alpine and intense solar radiation.

Travel early before the heat of the day, and avoid big slopes in the afternoon.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Cornices

Warm alpine temperatures will weaken the large cornices out there. Large loads have the potential to trigger the persistent slab weakness on loaded lee slopes.

Cornices become weak with daytime heating, so travel early on exposed slopes.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 29th, 2013 4:00PM