Avalanche Forecast

Issued: Apr 16th, 2015 4:36PM

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, Wet Slabs and Cornices.

tim haggarty, Parks Canada

Waterton Lakes.

Although Avalanche Hazard will persist as long as snow remains, we will no longer be producing regular avalanche bulletins for the 2014/2015 season. To contact Waterton Lakes National Park Visitor Safety staff call 403 762 1473 during business hours.

Summary

Weather Forecast

Freezing levels are forecast to climb to 3200m Friday. Cooling over the weekend will be short-lived ahead of a return to warm temps next week. This puts us into spring weather patterns with warm, sunny days and cold nights. In weeks to come, watch for spring storms to bring a return to winter conditions especially at upper elevations.

Snowpack Summary

Powerful heating has now created moist surface snow to mountain top. With freezing crusts will form. Recent snow combined with west winds have created hard windslabs in alpine areas over recent crusts that run to at least 2400m on even the shaded slopes. While snow exists as low as 1500m, very little coverage can be found below 2000m.

Avalanche Summary

As freezing levels reached mountain tops today avalanche activity spiked with loose wet avalanches to size 2 out of many of the steeper slopes. While there was some dry slab activity earlier in the week with recent snow failing over buried crusts, loose wet activity today was triggering these same slabs with more of a wet slab character.

Confidence

Problems

Loose Wet

As surface snow melts with heating it becomes weak and will fail. With momentum these events gain size and can easily entrain more snow especially as water lubricates a buried crust. Although these slides move slowly they pack a considerable punch.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Travel early on frozen crusts before the heat of the day.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2

Wet Slabs

Recently formed windslabs and many long buried weak layers will produce slab avalanches as the snowpack heats up and looses strength. Both Loose Wet and Cornice activity could provide a heavy load to a slope acting as a trigger to these waiting slabs

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Cornices

Cornices have grown to be quite large and are susceptible to the powerful solar heating at this time of year. A falling cornice can create a large avalanche on the slope it hits giving them surprising reach in their destructive potential.

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

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 17th, 2015 4:36PM