Avalanche Forecast

Issued: Apr 12th, 2018 3:33PM

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

jsmith, Avalanche Canada

Northwest Coastal.

Forecast new snow and strong winds Thursday night are expected to create fresh storm slabs reactive to human triggers in wind effected terrain.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

TONIGHT: 5-10 cm new snow. Strong to extreme southeasterly ridgetop winds. Freezing level around 500 m.FRIDAY: 5-10 cm new snow. Strong southerly ridgetop winds. Freezing level around 1000 m.SATURDAY: 5-10 cm new snow. Light southeasterly ridgetop winds. Freezing level around 1000 m.SUNDAY: Mix of sun and cloud. Light northeasterly ridgetop winds. Freezing level rising to around 1300 m.

Avalanche Summary

On Wednesday, a size 2.5 persistent slab avalanche was remotely triggered by a group of skiers on a ridgetop from 10 m away. The avalanche failed on surface hoar about 70 cm deep on a north aspect at 1800 m. A size 2 wet slab was triggered by day-time warming in the same area near Bear Pass.

Snowpack Summary

5-15 cm of new snow and strong southeasterly winds have formed fresh storm slabs.In the south of the region, two layers of surface hoar are buried approximately 70-100 cm deep. The layers are most prominent on north to east aspects and were buried early-March and mid-March. In the north of the region, these layers are around 40 cm deep.Bellow these March layers the mid-pack is generally well-settled and strong. However, shallower parts of the region, such as the far north, have weak sugary facets near the bottom of the snowpack.

Problems

Storm Slabs

New snow may bond poorly to an underlying crust. Watch for fresh storm slabs in leeward areas near ridge crests and convex features.

Watch for signs of instability such as whumphing, cracking, or recent natural avalanching.Use small slopes with low or no consequence to test the bond of the new snow.Use caution in lee areas in the alpine and treeline. Storm snow may form touchy slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Loose Wet

When the sun comes out it will quickly weaken the new snow and cause loose wet avalanching on steep solar slopes.

Avoid steep terrain that is in the sunshine.Watch for signs that the snow is heating up such as pin-wheeling or the surface snow becoming moist.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Apr 13th, 2018 2:00PM