Avalanche Forecast

Issued: Apr 5th, 2012 10:36AM

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

mbender, Avalanche Canada

South Columbia.

Summary

Confidence

Good

Weather Forecast

FRIDAY: Broken skies with locally light convective precipitation. Winds are light from the north and switching to the east in the afternoon. Freezing level hovering at 1600m. SATURDAY: A ridge of high pressure builds giving way to broken skies. Light southerly winds. Freezing level 1000-1200m. SUNDAY: The high pressure continues giving mostly clear skies and light west winds. Freezing level rising to 1600m.

Avalanche Summary

Recent reports are generally smaller avalanches (size 2) that are either wind slabs or moist loose slides due to solar warming. Previous reports from last weekend or early in the week include remotely triggered size 3 and a natural avalanche with a 2 km wide crown was reported on an east facing aspect which started in the storm snow and then stepped down to the March 27th crust/facet combo. These shouldn't be forgotten quite yet.

Snowpack Summary

Recent snow accumulations range from 20-40cm in the past 48hours. 90-120cm of snow from the past 7 days is now sitting on a reactive weak layer over a crust. Slopes below 1000 m continue to experience little or no overnight refreeze (recovery). The deeper early february surface hoar layers seem to have been unreactive in the short term but still remain a concern with very heavy triggers such as a cornice fall.

Problems

Storm Slabs

Bigger avalanches relating to a crust 40 to 80 cm deep especially on south facing slopes. Watch the sun and afternoon warming.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 5

Wind Slabs

Recent new snow combined with moderate winds creating new windslabs on northerly downwind slopes and cross-loaded terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Cornices

Large cornices keep getting bigger and more sensitive with continued wind, snow and warm temperatures. Cornices impacting slopes below could be considered enough of a load to trigger some of the deeper buried weaknesses.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 7

Loose Wet

Short periods of sun can be enough to trigger avalanches on sun exposed slopes.

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Apr 6th, 2012 9:00AM