Avalanche Forecast

Issued: Apr 6th, 2018 4:37PM

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

Avalanche Canada jmcbride, Avalanche Canada

New snow and wind beginning late Saturday afternoon will increase avalanche hazard.  If however, the storm arrives earlier than forecasted, hazard ratings will also increase sooner.

Summary

Confidence

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

Weather Forecast

TONIGHT: Mostly clear. Ridge wind light to moderate, west. Alpine temperature near -5. Freezing level valley bottom.SATURDAY: Increasing cloud, snow beginning in the afternoon. Accumulation 5-15 cm. Ridge wind moderate to strong, south. Alpine temperature near -3. Freezing level 1000 m.SUNDAY: Cloudy, flurries. Accumulation 5-10 cm by Sunday morning. Ridge wind moderate to strong, west. Temperature near 0. Freezing level 1800 m.MONDAY: Mix of sun and cloud. Ridge wind moderate, west. Alpine temperature near 0. Freezing level 1800 m.

Avalanche Summary

Numerous small slab avalanches have been reported in the top 10-25 cm of snow all through this week. It appears as though moderate amounts of new snow with just the right amount of wind have continuously set up thin, but touchy wind slabs in a variety of places. While these have been mostly small (size 1), a size 2 wind slab avalanche was reported near Fernie on Wednesday morning on a northeast aspect at approximately 2000 m.Explosive control work on Friday produced wind slab and cornice releases up to size 2 in alpine terrain.Thursday in the Elkford area, recent small (size 1) loose/dry avalanches were reported on northerly aspects while loose/wet were observed on solar aspects.Also, cornices are large along ridgetops and were actively failing last week.

Snowpack Summary

20-30 cm storm snow sits above a variety of crusts on all but high north aspects. Wind has formed isolated slabs in lee features, and in some cases snow may be poorly bonded to the crusts.There are some reports of a surface hoar layer roughly 80 cm deep on north aspects at treeline, but no recent avalanche activity on this layer. A layer of sugary facets around a crust exists near the bottom of the snowpack, but this layer has been inactive for some time.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs have been a consistent feature for several days and will continue to be an issue in exposed terrain. Shifting winds means you should look out for wind slab on almost all aspects.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Pay attention to overhead hazards like cornices which could easily trigger slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

An icon showing Cornices
Cornices are reported to be large and several cornice failures have recently been noted.
Extra caution needed around cornices with current conditions.Give cornices a wide berth when travelling on or below ridges.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1.5 - 2.5

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