Avalanche Forecast

Issued: Mar 27th, 2018 4:08PM

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

snow safety, Parks Canada

Little Yoho.

Unexpectedly heavy snow in Little Yoho combined with strong winds produced an avalanche cycle Tuesday. The snowpack is expected to be touchy and tricky for a while. Make conservative choices.

Summary

Weather Forecast

More light snow and strong winds, with moderately cool temperatures are forecast. More snow is expected Friday.

Snowpack Summary

Moderate to strong SW winds are creating wind slabs in alpine and treeline areas and beginning to over load cornices. 40+ cm of recent snow sits over a melt freeze crust on solar aspects with some facets at the crust interface. So far the lower snowpack has few concerns except for basal facets in shallow areas.

Avalanche Summary

Numerous avalanches to size 2.5 were noted on Mt Field and Emerald Pk

Confidence

Problems

Wind Slabs

Wind slabs and wind effect will increase on Tuesday with the arrival of new snow and continued W winds. We expect to see increased natural avalanche activity, especially as cornices get over loaded and fail, and human triggering will be likely.

Pay attention to overhead hazards like cornices which could trigger slabs.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Persistent Slabs

As the new snow increases the load over the March 15 crust on solar aspects we may start to see avalanche activity on this layer. If the facets below the crust also fail, larger propagations will be possible.

Watch for signs of instability such as whumpfing, or cracking. Recent snow may be more sensitive to human triggering on solar aspects where it sits on sun crust

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Mar 28th, 2018 4:00PM