Avalanche Forecast

Issued: Apr 7th, 2013 4:00PM

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

garth lemke, Parks Canada

Jasper.

Daytime and nightime temperatures are staying cooler. Winds have been variable directions so assess for reverse loading patterns on a buried smooth temperature crust. Tuesday's forecasted sun may briefly increase danger rating in the afternoon.

Summary

Weather Forecast

Sunday evening freezing level will be valley bottom rising to 1300m on Monday and light East winds. Expect a good freeze Monday night. Tuesday will be sunny, light Westerlies, with rising afternoon freezing level. Tuesday night will have less overnight freeze, 100km/hr Westerlies at 3000m, and moderate precipitation into Wednesday.

Snowpack Summary

Melt freeze crust below treeline provides stability above a wet and unconsolidated snowpack. Watch for daytime heating breaking the crust down and increasing the danger. Alpine cornices are large and looming. The snowpack is supportive above treeline with a light dusting of snow over a temperature crust particularly on South aspects.

Avalanche Summary

No new avalanches reported on Sunday. On Friday, several loose avalanches were observed from steep rock cliffs. Steep, Southerly aspects below 1600m are mostly melted out.

Confidence

The weather pattern is stable on Monday

Problems

Loose Wet

This is less of a concern with cooler temperatures but increases its probability if the sun comes out. New snow rests on a buried smooth temperature crust particularly on South aspects. The surface snow can quickly become wet and active with heat.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Cornices

These heavy features can fall unexpectedly triggering deep large avalanches. Select your route to avoid these features. Probability of cornice failure increases with daytime heating and sun.

Pay attention to overhead hazards like cornices.Cornices become weak with daytime heating.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Apr 8th, 2013 4:00PM