Avalanche Forecast

Issued: Feb 12th, 2017 7:52AM

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

ian gale, Parks Canada

Glacier.

The storm slab remains reactive at all elevations. Rising temperatures and solar heating will increase hazard.

Summary

Weather Forecast

Mainly cloudy today with scattered flurries and no significant precip. The alpine high should be -8*C with 20 km/h southwesterly winds, gusting to 55km/h. Freezing level is forecast to reach 1000m today. Monday/Tuesday a warming trend is forecast for the area with freezing levels possibly reaching above 2000m.

Snowpack Summary

55cm of storm snow and strong S winds have formed reactive storm slabs at treeline & above. On solar aspects this slab buries a suncrust that was showing sudden planer results in snowpack tests before the storm. The storm snow will need time to settle & bond to old snow surfaces. Underneath, the mid & lwr snowpack are unusually weak and facetted

Avalanche Summary

Thursday's storm triggered a massive natural avalanche cycle with avalanches to sz 3.5, most running the full extent of their paths to valley bottom. In Connaught sz 3's were reported from Mt Cheops & Frequent Flyer path ran across the normal uptrack! Artillery controlled avalanches to sz 4 and yesterday fresh naturals to sz 3 were observed again.

Confidence

Freezing levels are uncertain

Problems

Storm Slabs

Widespread reactive storm slabs have formed from previous heavy snowfall and strong winds overnight! If triggered they have potential to run full path. Reports came in of whumphing & low elevation slabs releasing below treeline yesterday.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.New snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

The Jan 25th sun crust is buried down approx 60cm. Previous to the storm it was whumphing, showing easy sudden results and reactive to human triggering. If the storm slab is triggered it has the potential to step down and trigger this layer.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 13th, 2017 8:00AM