Avalanche Forecast

Issued: Apr 17th, 2016 4:41PM

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.

Ruari Macfarlane, Parks Canada

Waterton Lakes.

Summer-like weather will dominate this week. With light winds and high temperatures, you'll be seeking out summery activities! Keep in mind that upper reaches of hiking trails are still snowbound, and travel through avalanche runout zones.

Summary

Weather Forecast

A real heat wave is forecast, with the freezing level climbing steadily on Monday, to hover around 3800m for Tuesday and Wednesday. That's about as high as the top of Mt Robson! Mainly sunny skies and light winds don't promise much cooling, although on the clearest nights we could get some very temporary surface crust recovery.

Snowpack Summary

The snowpack is isothermal (punchy and wet to ground). Surface and near-surface Crusts may recover briefly after cool, clear nights, but will rapidly break down with the new day. North aspects in the alpine may be an exception, where 15cm of recently fallen snow will probably be moist, overlying a crust. Low, sunny slopes in the East are dry.

Avalanche Summary

Numerous small (Size 1 - 1.5) Loose Wet avalanches were observed on Friday and Saturday, as 20cm of cold storm snow became moist. A Size 1 cornice fall was observed on Sunday morning.

Confidence

Problems

Loose Wet

Expect loose wet avalanches initiation to spread to moderate-angled terrain, as the snowpack becomes totally isothermal. Later in the forecast period, these could gouge to ground and entrain alot of mass.

Travel early before the heat of the day, and avoid big slopes.If off-trail travel is deep and punchy, avoid all avalanche terrain, including runouts.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Wet Slabs

The free water generated by snowmelt will make ground surfaces wet, possibly causing areas with existing glide cracks to avalanche to ground. These avalanches would be very large.

Avoid slopes with glide cracks.Avoid exposure to overhead slopes with Glide Cracks. Avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Cornices

We expect increasing occurrences of natural cornice failures, due to sustained high freezing levels.

Minimize exposure to overhead hazard from cornices.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 20th, 2016 4:00PM