Avalanche Forecast

Issued: Feb 24th, 2016 8:00AM

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

ian gale, Parks Canada

Glacier.

The sun should be out today & freezing level is on the rise! With this heat the wind and storm slabs will become more reactive. Limiting exposure to overhead hazards like sunny start zones and cornices are key.

Summary

Weather Forecast

A high pressure system is in place now that will be around until the weekend. Today will bring a mix of sun and cloud and temps are starting to climb up. Alpine highs today of -3, freezing level to 1500m & ridge wind 10-20km/hr.

Snowpack Summary

Previous new snow has been blown around at ridgetop building a variable softslab in the Alpine. This overlies a previous windslab & both these slabs are sensitive to human triggering. There are still easy shears in the storm slab aswell but overall the snowpack is gaining strength. The Feb 10 surface hoar is dn 60-100cm and may still be triggered.

Avalanche Summary

Yesterday we had a few loose moist avalanches from steep South & West facing slopes. On the 21st there was a skier triggered sz 1.5 on Little Sifton col, the skier was involved but uninjured. The slide was 25cm deep, 50m wide & ran 70m. There was also BIG (up to sz 4)avalanches in the Asulkan &Loop valleys from cornices failing during solar warming

Confidence

Problems

Wind Slabs

Touchy windslab in the immediate lee of ridgelines and crossloaded features formed Fri from mod S winds (the skier triggered slide on Sifton col is a good example). This older wind slab is now buried under a new soft Wsl from mondays snow and wind

Use caution in lee areas. Recent wind loading have created wind slabs.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Storm Slabs

Storm slabs are generally gaining strength but may still be sensitive to human triggering given the right terrain feature. Steep planar slopes should be investigated before jumping in. Avoid unsupported or convex terrain.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Persistent Slabs

Feb 10 interface lingers and is becoming difficult to forecast. In some areas there is surface hoar on a crust which is a good recipe for bad avalanches. It may become reactive given prolonged sun or added load such as cornice fall or slab avalanche

Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 25th, 2016 8:00AM