Avalanche Forecast

Issued: Apr 9th, 2015 4:00PM

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

tim haggarty, Parks Canada

Waterton Lakes.

Following an active week for avalanche activity, cooling this weekend should slow things down. With luck, a bit of snowfall could freshen things up. Snow removal has begun on the Cameron Lake Road although the barriers remain in place.

Summary

Weather Forecast

Friday will bring a return of the strong west winds for the period with freezing levels reaching 2500m following a poor recovery overnight. The clouds that develop Friday will precede a cold front dropping down the West side of the divide Saturday that should bring cooling and up to 10cm of snow above 1900m. Cool temps and cloud will persist Sunday

Snowpack Summary

Early this week, W and N winds created widespread wind slabs Treeline and above with the 20cm of snow that fell this weekend. This snow sits on a solid crust found everywhere but above 2400m on N aspects. New surface crusts have formed everywhere but above 2400m on N aspects and widespread loose dry and wet activity has affected snow surfaces.

Avalanche Summary

Loose dry activity to sz 2 started early this week. As temperatures climbed Tuesday through Thursday, loose wet activity to ridgetops could be seen on all but alpine shaded slopes to sz 1.5. Some significant slab avalanches and cornice failures to sz 2.5 have been seen along ridgecrests faces in alpine and high treeline terrain.

Confidence

Due to the number of field observations

Problems

Wind Slabs

Widespread slabs up to 50cm deep formed over a crust early this week are likely to be found along ridge crests and in cross loaded features within a slope. Watch for these on the hunt for dry high elevation north facing snow.

Use caution in lee areas in the alpine and treeline. Recent storm snow has formed touchy slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

As the freezing levels remain high overnight Thursday and into Friday with the potential for some solar heating watch for continued activity as surface crusts break down. The recent snow has proven to be quite reactive over the buried crust.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Cornices

The recent growth that has developed on the cornices is quite fragile. Several failures have occurred during this week, some pulling windslabs and others triggering loose activity at lower elevations to run a significant distance overall.

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 12th, 2015 4:00PM