Avalanche Forecast

Issued: Feb 15th, 2019 4:14PM

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

Tim Haggarty, Parks Canada

Little Yoho.

The polar push is back.Expect light snow accumulations and variable winds to affect conditions through the weekend as arctic air moves in from the prairies.

Summary

Weather Forecast

After a brief taste of a westerly flow and mild temperatures, the arctic air is pushing back again late Friday. With this push, temperatures will drop, winds will shift to northerly and light accumulations of cold snow are expected Saturday. Watch for temperatures to drop further into Sunday as skies start to clear.

Snowpack Summary

30 to 40 cm of snow has fallen since Feb 2. This has been affected by variable winds, isolated periods of intense solar radiation and most notably, sustained cold temperatures promoting faceting. Down 50 to 75cm, Jan 17 surface hoar produces sudden planar shears in isolated locations treeline an below. A weak basal snowpack exists in shallow areas

Avalanche Summary

No new avalanches observed or reported.

Confidence

Intensity of incoming weather systems is uncertain on Saturday

Problems

Wind Slabs

Variable winds through the weekend are expected to move alpine snow around. Although slab formation will likely be slow with cold dry snow, the bond to the dry, faceted surface snow will be weak.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Variable winds may create pockets of wind slab in some unexpected locations.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Loose Dry

A sustained period of cold weather has driven the faceting process in the upper snowpack creating weak, dry surface snow. In steep terrain, these are sensitive to small natural and human triggers and can quickly gain enough mass to affect travelers.

Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.Good group management is essential to manage current conditions safely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 1

Valid until: Feb 16th, 2019 4:00PM