Avalanche Forecast

Issued: Dec 7th, 2015 8:04AM

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

percy woods, Parks Canada

Glacier.

We are at the touchy upper end of Considerable trending toward High avalanche danger. Conservative route selection is paramount.

Summary

Weather Forecast

A large pulse of warm precipitation is coming at us from the SW bringing upwards of 40mm of precipitation by Tuesday afternoon. Freezing levels are expected to rise to over the 2000m level.

Snowpack Summary

We are closing in on critical loading on the weak Dec 2 surface hoar layer down anywhere from 25-50cm. The building storm slab will overload this layer resulting in a widespread avalanche cycle. Look for a steadily increasing avalanche danger.

Avalanche Summary

Natural avalanches and skier triggered slides in the 1-1.5 size range were reported yesterday. Numerous avalanches were recorded in the highway corridor. These slides all appeared to be releasing on the Dec 2nd surface hoar layer. Field tests on a SE aspect at 2000m on Grizzly Shoulder gave a Rutch block 3 full block 50cm down on a sun crust.

Confidence

Timing of incoming weather systems is uncertain

Problems

Storm Slabs

The Dec 2nd surface hoar layer is reaching critical overloading by the storm slab. Expect the storm slab to be reactive to both human and natural triggering.

Minimize overhead exposure during periods of heavy loading from new snow, wind.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

Windloading has formed windslabs on alpine and treeline northerly aspects. In some locations these slabs will be resting on the Dec 2nd surface hoar layer and will be sensitive to human triggering.

Use caution in lee areas. Recent wind loading have created wind slabs.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Dec 8th, 2015 8:00AM