Avalanche Forecast

Issued: Apr 6th, 2018 3:56PM

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

jmcbride, Avalanche Canada

Northwest Inland.

Strong to extreme winds have created wind slabs in leeward areas. Avoid freshly wind-loaded slopes and features, these may be primed for human triggering.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

TONIGHT: Flurries. Accumulation trace. Ridge wind light to moderate, southeast. Alpine temperature near -10. Freezing level valley bottom.SATURDAY: Mix of sun and cloud. Ridge wind strong, southeast. Alpine temperature near -3. Freezing level 1200 m.SUNDAY: Mix of sun and increasing cloud. Ridge wind moderate, southwest. Alpine temperature near -2. Freezing level 1500 m. MONDAY: Mix of sun and cloud, light flurries. Accumulation trace. Ridge wind moderate to strong, southwest. Alpine temperature near -1. Freezing level 1500 m.

Avalanche Summary

A widespread natural avalanche cycle (up to size 2), triggered by intense wind loading was reported from the northern part of region on Thursday.A natural, solar triggered size 2 avalanche was reported on Wednesday morning in the Howson range, as well as skier triggered size 1 storm slab releases on a buried sun crust (30 cm deep) on a southeast aspect at 1700 m.Friday of last week, a natural avalanche cycle up to size 2-3 occurred in response to storm snow loading.

Snowpack Summary

From 20 cm up to 40-50 cm of recent storm snow is being redistributed by strong winds and sits above a variety of crusts on all but high north aspects.Weak layers buried around March 19th are roughly 40 cm below the surface (up to 100 cm in deeper snowpack areas). These weak layers include surface hoar on shaded aspects at high elevations and hard crust layers on solar aspects and below treeline.Near the bottom of the snowpack, weak and sugary facets are found in shallow, rocky snowpack areas. Storm slabs have stepped down to these facets and producing very large avalanches in northern parts of the region.

Problems

Wind Slabs

Strong to extreme winds have created touchy wind slabs on leeward and cross-loaded slopes at treeline and above. While natural activity has likely tapered off, expect these slabs to remain primed for human triggering.

Be careful with wind loaded areas, especially near ridge crests and roll-overs.Use caution in lee areas. Recent wind loading has created wind slabs.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Valid until: Apr 7th, 2018 2:00PM