Avalanche Forecast

Issued: Mar 27th, 2013 11:00AM

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

mpeter, Avalanche Canada

Northwest Coastal.

Summary

Confidence

Good

Weather Forecast

Thursday: Expect few clouds with light westerly winds and alpine temperatures reaching -2.Friday & Saturday: The pattern continues, with mostly sunny skies, light westerly winds and alpine temperatures climbing to -1 in the afternoons.

Avalanche Summary

Natural and rider triggered avalanches up to 2.5 have been reported, likely triggering on the March 9th layer. Loose wet sluffs up to 2.0 have also been reported

Snowpack Summary

Recent new snow is settling with the influence of warm temperatures. Solar aspects now sport a melt freeze crust. Wind slabs may be found at alpine and treeline elevations on many slope aspects due to variable winds. A layer of surface hoar (buried March 9th; now down about 40-60 cm) is slowly becoming less touchy, but professionals are keeping a wary eye on it. In some places this interface is a crust/facet layer. Triggering this layer is becoming a low probability but high consequence problem. Check out the?Forecaster's Blog?for related discussion. A second surface hoar layer, buried on March 18, is also reported to be gaining strength. The mid snowpack is generally well settled and strong. Cornices are large and untrustworthy, especially when the sun is out.

Problems

Persistent Slabs

While the likelihood of triggering is slowly dropping, the March 9th layer can be triggered from a distance, propagate across large distances and create surprisingly large avalanches.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Choose regroup spots carefully.>Remote triggering is a concern, watch out for adjacent slopes.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 7

Wind Slabs

Watch for wind slabs behind ridges and ribs and in cross-loaded gullies. Cornices are also large and untrustworthy, especially on hot days.

Be cautious as you transition into wind affected terrain.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Loose Wet

Expect loose wet sluffs to trigger in the afternoon when the sun is at its strongest.

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

Likely

Expected Size

1 - 3

Valid until: Mar 28th, 2013 2:00PM