Avalanche Forecast

Issued: Mar 12th, 2024 4:00PM

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.

CG, Avalanche Canada

Glacier.

Reactive storm slabs are present where wind has stiffened the snow surface at Alpine and Tree-line elevations.

The strong Spring sunshine and warm temps will actively trigger avalanches on sunny slopes in the upcoming days.

Remote triggering of large avalanches is still a concern with a robust crust lurking ~1m below the surface.

Summary

Confidence

Moderate

Avalanche Summary

Natural avalanche activity in the hwy corridor has corresponded with wind spikes in the unsettled weather the last few days. Numerous avalanches up to sz 3 were observed Monday both E and W of the Pass. These were believed to be running in the new storm snow or on the reloaded Feb 3 bed surface.

Last Thursday, we observed naturally-triggered size 3 slab avalanches from Catamount Mtn SE face and Mt. Leda NE face. These were both deep, likely failing on the Feb 3rd crust.

Snowpack Summary

A 30-40cm storm slab now rests upon variable old surfaces: a thin suncrust on South & West aspects; previous wind effect from variable winds in open terrain; and settled powder in sheltered areas.

80-140cm of settled snow sits atop a sugary facet layer. These facets are not bonding well to the widespread, very firm crust from Feb 3rd. This crust is a significant persistent weak layer and will be the main layer of concern for the foreseeable future.

Weather Summary

A ridge builds over BC, resulting in clearing skies, slackening winds, and rising freezing levels (FZL).

Tonight: Clear periods, isolated flurries, trace, low -9Â°C, light W winds, FZL 500m.

Wed: Mix of sun/cloud, Alp high -8Â°C, light W winds, FZL 1300m.

Thurs: Sun/cloud, Alp high -1Â°C, light W winds, FZL 1600m

Fri: Sun/cloud, Alp high 4Â°C,, light NW winds, FZL 2800m

Terrain and Travel Advice

Watch for fresh storm slabs building throughout the day.
Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
Remote triggering is a concern, avoid terrain where triggering slopes from below is possible

Problems

Storm Slabs

Storm snow was accompanied by gusty SW winds. This built reactive soft slabs in lee areas. If triggered, these slabs may provide enough mass to trigger the deeper Persistent Weak Layer.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1.5 - 2.5

Persistent Slabs

This crust-facet combo (Feb 3rd) was created by a rain event followed by an extended cold, clear period without snow earlier this month. 80-140cm now sits on the persistent weak layer. Human-triggered avalanches on this layer remain possible, and resulting avalanches could be very large in size.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Mar 13th, 2024 4:00PM