Avalanche Forecast

Issued: Apr 18th, 2015 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 and Cornices.

conrad janzen, Parks Canada

Banff Yoho Kootenay.

Good spring skiing with fresh snow over a supportive base. Travel is fast and it is a good time for longer objectives. Start early when the hazard is Low and finish before the solar aspects get hot. Expect a winter like snowpack on high N aspects.

Summary

Weather Forecast

Generally clear skies Saturday night with a mix of sun and cloud on Sunday. Expect a good freeze Saturday night with freezing levels climbing to 2100m late Sunday afternoon. Monday and Tuesday will see temperatures begin to climb with potential for 3000m freezing levels by Tuesday afternoon.

Snowpack Summary

Supportive crust on solar aspects for most of the day with 5-10cm of new snow at higher elevations. Previous wind effect in alpine areas. Mid pack is well settled with no significant shears. The basal facets remain the main weakness in the snowpack, but we expect only large loads or a dramatic rise in temperatures to cause failures on this layer.

Avalanche Summary

Wet loose natural avalanches up to size 2 were seen Friday afternoon due to the warm temperatures with less activity on Saturday. Isolated whumpfing in the alpine was still noted on a steep solar aspect today in the Mt Hector area. Several recent cornice failures have triggered slabs on the basal facets and cornices remain a significant concern.

Confidence

Problems

Loose Wet

Expect solar triggered avalanche activity on steep solar aspects Sunday afternoon. It is possible that wet slides could trigger the basal facet layers if they have enough mass. Start early and be off steep solar aspects by midday.

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

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Cornices

Many large cornices have formed recently, and there have been numerous reports of cornice failures over the last week. In isolated events these have been big enough to trigger the deep basal facets.

Extra caution needed around cornices with current conditions.Cornices become weak with daytime heating, so travel early on exposed slopes.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 19th, 2015 4:00PM