Avalanche Forecast

Issued: Apr 4th, 2012 4:00PM

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

istorm, Avalanche Canada

South Columbia.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

The effect of Wednesday's storm should mostly be from the wind because forecast precipitation amounts are light. Thursday through Saturday should see generally light wind, little to no precipitation beyond local showers, sunshine in the morning with mixed afternoons, and gradually warming daily maximum temperatures. Good freezing overnight with afternoon freezing levels to near 1500m.

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

The most recent storm produced 40 - 100 cm of total snowfall, with the far south of the region receiving the greater accumulations. 80-100cm of storm snow from the past 7 days is sitting on a weak layer of Facets sitting on a crust. This layer seems to be most reactive on sun exposed slopes. 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.

Problems

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

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: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 5

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 ben 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 5th, 2012 9:00AM