Avalanche Forecast

Issued: Mar 10th, 2013 10:32AM

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

Avalanche Canada slemieux, Avalanche Canada

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

Sunday night and Monday: A quasi-pineapple express is setting over the region that could last till Wednesday. On and off precipitation should start Monday with light to moderate NW winds. Temperatures are forecasted to start to warm up in the alpine (-3 C) and freezing levels to rise to 1300 m.Tuesday: Moderate to heavy precipitation are expected for the region with moderate to strong winds from the SW. Freezing levels rising to 2000 m.Wednesday:  Another frontal system is moving across the region which could give more moderate precipitation and slightly similar mild temperatures but with lighter winds from the same direction.

Avalanche Summary

Widespread natural and skier triggered moist loose avalanche activity on solar aspect up to size 2. There was also report of sluffing on steep northerly aspect.

Snowpack Summary

Recent windslabs have formed on lee features with W and E winds in the alpine and below ridgetops at treeline. These will still be susceptible to sledder and skier triggering. Outside of wind effected areas, I suspect that the top snowpack is generally gaining strength and starting to bond to the underlying surfaces. The 25-30 cm of snow from earlier this week is sitting on an older snow interface above 2000 m. and on a melt freeze crust below that elevation. Up to 80 cm snow overlies a surface hoar and sun crust which is becoming less reactive to skier traffic but that is still a concern to professionals. At the surface, there is a suncrust on SE-S-SW facing slopes all the way up in the alpine, a melt-freeze crust up to 1800 m. and some surface hoar on shaded slopes above that elevation.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs have formed recently and are prone to skier triggering especially where they sit on the buried melt-freeze crust below 2000 m.
Be extra cautious on exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Carefully evaluate bigger terrain features by digging and testing on adjacent, safe slopes.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 5

Persistent Slabs

An icon showing Persistent Slabs
The 80 cm deep surface hoar/sun crust weak layer could be triggered by a cornice fall or an slab avalanche stepping down.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Mar 11th, 2013 2:00PM