Avalanche Forecast

Issued: Mar 22nd, 2013 10:03AM

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

pgoddard, Avalanche Canada

Sea To Sky.

Avalanche danger may spike on slopes receiving direct sun. Avoid travelling on or underneath sun-baked terrain.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Saturday-Monday: Mainly sunny with clear skies and light winds. Alpine temperatures near -5, dropping overnight.

Avalanche Summary

Natural cornice fall triggered size 1-2.5 slabs within recent storm snow on Thursday. Skiers also triggered wind loaded slopes to size 2. Intense wind-loading triggered several wind slabs, mainly on north aspects at alpine and treeline elevations, on Wednesday. Skiers also triggered size 1-2 storm/wind slabs.

Snowpack Summary

Recent snowfall was redistributed by very strong SE to SW winds, leaving wind slabs 30 cm to 1 m deep on many lee terrain features. Subsequent NW winds may have caused some reverse loading - so keep an eye out for wind slabs on all aspects. The upper snowpack structure is highly variable. On sunny aspects (and all aspects at low elevations), a sun/melt-freeze crust is now buried about 30 cm deep, while on high elevation shady aspects, 50-100 cm snow overlies an older melt-freeze crust. Mid and lower snowpack layers are well bonded.

Problems

Wind Slabs

It may be possible to trigger slabs in steep terrain or on convex shaped slopes. Variable winds may have left slabs on many slopes.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Cornices

Cornices are reported to be very large and may fail with solar warming. They are a danger in themselves and could also trigger a slab avalanche on the slope below.

Avoid steep slopes below cornices.>Stay well to the windward side of corniced ridges.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

3 - 6

Loose Wet

Direct sun may trigger loose snow avalanches on steep sunny slopes.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Be aware of what is above you at all times.>

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Mar 23rd, 2013 2:00PM