Avalanche Forecast

Issued: Apr 14th, 2018 4:36PM

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

tim haggarty, Parks Canada

Little Yoho.

Be aware that it is still winter in the alpine! While recent wind and snow has created some touchy new slabs, these have remained quite small to this point, watch for continued snow and slightly warmer temperatures to potentially raise the hazard.

Summary

Weather Forecast

It is still winter up high! A short break following Saturday's wind and snow before another pulse of 10 -20 cm for Sunday through Monday, with what are forecast to be lighter South, shifting East, winds. Freezing levels may crest 2200m Monday and Tuesday with yet another pulse of snow in the forecast for late in the day Tuesday.

Snowpack Summary

10 - 20 cm of new snow over the last 48 hours with wind effect from moderate - strong SW winds. Buried temperature crusts exist to 2000m on all aspects and higher on solar slopes. The March 15 sun crust is down 25-50 cm on solar aspects in the alpine, this, and shallow areas harboring weak facets remain worth watching as temperatures slowly climb.

Avalanche Summary

The recent snow and winds continue to form touchy new slabs: Skiers on the Chickadee - Boom traverse observed a sz 1.5 Na in NE facing alpine terrain and passed on a report of a skier triggered avalanche on the SE slope of the Whymper traverse. Skiers also reported easy triggering of soft slabs on test slopes near around the Crowfoot glades.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Sunday

Problems

Wind Slabs

Gusty winds and new snow have formed touchy soft slabs that are reacting easily to skier traffic and starting to fail as natural events. Watch for another pulse of snow to either contribute to these slabs or potentially hide them.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

While it has been a few days since there has been any confirmed events directly associated with the March 15 crust, other crusts have now become buried in similar locations. Forecasters still voice caution with all of these potential sliding layers.

Be cautious with convexities and steep slopes on solar aspects.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2.5

Cornices

There have been a few recent cornice failures mainly associated with the recent wind and snow but as temperatures climb a bit higher than they have been Monday and Tuesday it would be wise to keep these in mind.

Pay attention to overhead hazards like cornices which could trigger slabs.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 15th, 2018 4:00PM