Avalanche Forecast

Issued: Mar 18th, 2013 10:55AM

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

pgoddard, Avalanche Canada

South Rockies.

The effect of sunshine could cause a spike in avalanche danger on Tuesday.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Tuesday

Weather Forecast

Monday night: Light snow. Strong W winds. Alpine temperature near -16.Tuesday: No snow. Sunshine. Moderate to strong W winds. Alpine temperature near -10.Wednesday: Moderate snow. Strong to extreme SW winds. Alpine temperature near -4.Thursday: Moderate to heavy snow. Light to moderate SW winds. Alpine temperature near -8.

Avalanche Summary

Observations were limited during Sunday's storm, but large avalanches were heard running in steep terrain. Skiers also triggered small soft slabs which failed on the buried crust.

Snowpack Summary

Up to 50 cm snow overlies a crust, which is supportive to at least 2100 m in most areas. Ridge top winds have been from SW and NW directions, creating pockets of wind slab on a variety of lee and cross-loaded slopes. Deeper in the snowpack, a series of crust layers (or isolated surface hoar) makes up the upper snowpack. The mid-pack is reported to be generally well-settled. Cornices are large and fragile in some areas.

Problems

Wind Slabs

Be alert for wind slabs behind ridges and terrain breaks.

Use ridges or ribs to avoid pockets of wind loaded snow.>Be wary of travelling on loaded fans below steep faces when hill climbing.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Loose Dry

Recent storm snow can slide easily on a buried crust. It may have enough force to trip you up or carry you into a terrain trap.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>On steep slopes, pull over periodically or cut into a new line to manage sluffing.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Loose Wet

Be wary of travelling on or below steep slopes which are being warmed by direct sun. Storm snow may fail naturally with the influence of solar radiation.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Be alert for areas with overhead hazard.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 19th, 2013 2:00PM