Avalanche Forecast

Issued: Mar 4th, 2014 8:40AM

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

Avalanche Canada jlammers, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain on Wednesday

Weather Forecast

Overview: A zonal pattern will continue to bring moisture to the Columbia Mountains, particularly for Wednesday and Thursday. Expect higher freezing levels and greater accumulations further south within the region.Wednesday: 10-15cm of snow falling late in the day and overnight / Moderate westerly winds / Freezing level rising from surface to about 800m with the arrival of the system Thursday: Light snowfall / Moderate westerly winds / Freezing level at about 1200mFriday: Overcast skies / Moderate northwest winds / Freezing level at about 1200m

Avalanche Summary

Numerous size 2-2.5 sled-triggered slab avalanches occurred in the Valemount area over the last week. The February 10th interface was the culprit in these events. At the time of publishing, no new avalanche activity had been reported.

Snowpack Summary

In general, about 15-25cm of storm snow overlies small surface hoar crystals in sheltered areas, a sun crust on solar aspects and wind slabs in exposed terrain. Initially, these new accumulations are expected to be reactive as wind slab in pockets of exposed terrain. Once the new slab develops, more widespread storm slab activity can be anticipated.There is ongoing concern for a mix of weak surfaces which were buried on February 10th. This persistent interface lies up to a metre below the surface, and includes weak surface hoar, well developed facets and a mix of hard surfaces which remain widespread at all aspects and elevations. Although natural avalanche activity has tapered-off at this interface, destructive avalanches are still a very real concern with ongoing reports of rider-triggering and sudden snowpack test result results. For the most part, the mid and lower snowpack are strong and well consolidated. Weak basal facets exist in some areas, but triggering has now become unlikely.

Problems

Persistent Slabs

An icon showing Persistent Slabs
A deep, dense slab overlies a variety of weak layers and may still be touchy in some areas. Triggering this weakness would have nasty consequences, so be patient and don't be tempted by large, unsupported terrain.
Avoid convexities or areas with a thin or variable snowpack.>Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Wind Slabs

An icon showing Wind Slabs
Continued snowfall and moderate winds are forming new wind slabs which may overlie existing reactive wind slabs. Watch for triggering in gullies, and in the lee of ridge crests and terrain breaks.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Be careful with wind loaded pockets, especially near ridge crests and roll-overs.>The recent snow may now be hiding windslabs that were easily visible before the snow fell.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 5th, 2014 2:00PM

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