Avalanche Forecast

Issued: Feb 24th, 2014 8:14AM

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

swerner, Avalanche Canada

Kootenay Boundary.

Don't let the improving weather lure you into high risk scenarios. Conditions remain very tricky.Avalanche danger can rise quickly with the first day of full sun.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

The strong arctic ridge will continue to push modified arctic air across the region. Clear and dry conditions will persist until Thursday. Some unstable disturbances are embedded in this flow, bringing some scattered cloud later in the week.Tuesday: Mostly sunny. Treeline temperatures -2.0. Ridgetop winds are light and variable. Freezing levels rising to 1100 m. Wednesday: Sunny in the am with some cloud. Treeline temperatures near 1.0. Ridgetop winds light from the north. Freezing levels 1800 m.Thursday: Mix of sun and cloud. Alpine temperatures near 1.0. Ridgetop winds moderate from the northwest. Freezing levels 1500 m.

Avalanche Summary

On Sunday, a skier triggered size 2.5 was reported. Party of three with two involved. Sadly RCMP reported one fatality and the other suffered serious injuries. The crown was near 100 cm deep and released near ridgetop in storm snow and then stepping down to the persistent weak interface and running a far distance through the trees. Remote triggering and long fracture propagations are occurring on all aspects and elevations. With forecast sun, the avalanche hazard will likely increase on solar slopes.Check out the Forcaster Blog! It shows a photo of a remote triggered size 3 last Friday in the southern part of the Kootenay-Boundary.

Snowpack Summary

Changing winds from the southwest-north may build fresh wind slabs on leeward slopes. Currently there is over a metre of recent storm snow that is sitting on a weak layer comprising of facets, surface hoar, melt-freeze crusts and any combination of these. The weak layer is widespread at all elevations and aspects and continued whumpfing and easy sudden planar snowpack test results are being reported. The storm slab continues to settle and become more cohesive allowing for longer fracture propagations and remote triggering from up to 200 m away, yikes! This persistent weak layer is expected to be a concern for some time; at all elevations and aspects. Treeline and below treeline elevations is catching many people by surprise.With forecast sunny periods, solar aspects will likely see some changes and become more reactive.

Problems

Persistent Slabs

Expect the deeply buried weak layers to continue to produce large and destructive avalanches. Slopes are primed for human triggering and remain a concern on all aspects and elevations.

Use conservative route selection and resist venturing out into complex terrain, even if you observe no obvious signs of unstable snow.>Remote triggering is a big concern, be aware of the potential for wide propagations and large, destructive avalanches at all elevations.>Avoid areas with overhead hazard, especially on solar aspects.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

3 - 6

Wind Slabs

Wind has transported snow and built fresh, touchy wind slabs. Be aware of weak cornices looming over slopes. If they fail, they will likely trigger a large slab avalanche on the slope below.

Caution in lee and cross-loaded terrain near ridge crests.>Avoid freshly wind loaded features.>Extra caution needed around cornices with current conditions.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Feb 25th, 2014 2:00PM