Avalanche Forecast

Issued: Mar 15th, 2018 4:37PM

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

jmcbride, Avalanche Canada

Purcells.

There is some snow on the way but forecasted amounts are not expected to have much impact on hazard ratings. Watch for pockets of lingering wind slab at upper elevations.

Summary

Confidence

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

Weather Forecast

TONIGHT: Flurries. Accumulation 5-10 cm. Ridge wind light, southwest. Alpine Temperature near -5. Freezing level 700 m.FRIDAY: Cloudy, light flurries. Accumulation trace. Ridge wind light, northeast. Alpine Temperature near -6. Freezing level 1700 m.SATURDAY: Mostly cloudy, flurries. Accumulation 5-10 cm. Ridge wind light, east. Alpine Temperature near -4. Freezing level 1600 m.SUNDAY: Mostly cloudy, light flurries. Accumulation 2-6 cm. Ridge wind light, northwest. Alpine Temperature near -5. Freezing level 1500 m.

Avalanche Summary

Numerous wet loose avalanches were observed in the region to size 2.5 over the past several days on sunny aspects. As well as both skier and sledder triggered wind slabs up to size 1.5 on south east to west aspects On Sunday we received reports of a skier caught in a size 2.5 avalanche in the north of the region. The slab was 20-50 cm thick and started on a steep north east aspect immediately below ridge crest at 2300m. See the MIN post for more details.

Snowpack Summary

A light dusting of new snow now covers a crust on all but high elevation northerly aspects which still hold loose, dry snow above a generally well-settled snow pack.A couple of layers buried in mid-late February (down around 40-100 cm) have shown limited reactivity of late. Persistent slabs have been triggered on shady aspects, where surface hoar and/or facets exist. Deeper persistent weak layers from January and December are generally considered dormant, but could wake up with a surface avalanche stepping down, cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets. Facets also linger at the base of the snowpack.

Problems

Wind Slabs

Pockets of reactive wind slab can still be found in leeward areas in the alpine. In the northern part of the region, these slabs may be sitting on a layer of surface hoar on shaded aspects at treeline as well.

Give cornices a wide berth when travelling on or below ridges.Watch for wind loaded pockets near ridge crests and roll overs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 16th, 2018 2:00PM