Avalanche Forecast

Issued: Mar 23rd, 2013 9:52AM

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

pgoddard, Avalanche Canada

Sea To Sky.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Sunday-Tuesday: A mix of sun and cloud with light winds. A few flurries are possible on Tuesday. Alpine temperatures near -2, dropping during overnight periods.

Avalanche Summary

Skiers triggered size 1 and 2 slabs on convex terrain features on Friday. These were on east and north aspects at alpine and treeline elevations. They failed on crust or old hard wind slab layers. Solar warming also triggered a few small loose wet avalanches on steep sunny slopes.

Snowpack Summary

Wind slabs, which recently formed on a widespread basis, are becoming harder to trigger. Large cornices are looming over some slopes. On sun-baked slopes, a melt-freeze cycle is in play at the snow surface, leaving a crust behind during overnight cooling, which breaks down by day. The upper snowpack structure is highly variable. On sunny aspects (and all aspects at low elevations), a 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. Bonding at both of these crust interfaces appears to be improving, but they are still in the back of professionals’ minds. 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. Cornices are looming in some areas.

Use ridges or ribs to avoid pockets of wind loaded snow.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 5

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.>

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Mar 24th, 2013 2:00PM