Avalanche Forecast

Issued: Apr 28th, 2014 4:00PM

The alpine rating is low, the treeline rating is low, and the below treeline rating is low. Known problems include Wind Slabs and Deep Persistent Slabs.

grant statham, Parks Canada

Banff Yoho Kootenay.

Tuesday will be an excellent day. A good freeze is expected on Monday night followed by a sunny, cool day on Tuesday. BUT, on Wednesday the warm air arrives with freezing levels to 3500m. The first big warm up day usually produces an avalanche cycle.

Summary

Weather Forecast

Clear skies and a low of -10 on Monday night followed by a sunny day on Tuesday with highs of 4. Tuesday is the day to get out there! Wednesday we finally get the big warm up we've been waiting for, with freezing levels expected to reach 3500m, and going higher on Thursday. Highs on Wednesday toÂ 12 degrees, with valley bottoms in the upper teens.

Snowpack Summary

All areas of the park have a strong melt-freeze crust up to about 2400 meters, slightly bit lower on north aspects. Above that, dry snow persists with up to 20 cm of settled powder in shaded areas. Isolated, small windslabs exist in leeward areas in the alpine. Temperatures on Monday of -9 at 3000 m and a light north wind kept the snowpack stable.

Avalanche Summary

No new avalanches were observed or reported on Monday.

Confidence

on Wednesday

Problems

Wind Slabs

Over 20 cm of snow has fallen over the past few days at the higher elevations which has been blown into small pockets of windslab in isolated locations. Today we avoided one that was 40cm deep and directly below a cornice.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Deep Persistent Slabs

Until we go through a major melt-freeze cycle, this problem will remain. While not expected to produce avalanches when the temperatures remain cold, once the warm air arrives we expect another round of large avalanches on this layer. Wednesday?

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

3 - 4

Valid until: Apr 29th, 2014 4:00PM