Avalanche Forecast

Issued: Apr 6th, 2015 9:10AM

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

bcorrigan, Avalanche Canada

Northwest Coastal.

The forecast hazard may go higher on specific terrain features, especially in the afternoon with daytime heating

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Clear and sunny for the next few days with the next Pacific frontal system forecast to arrive on the coast late Wednesday. Freezing levels will rise with daytime heating to 1300m and drop overnight to near valley bottoms. Winds should be mostly light from the south

Avalanche Summary

Several large natural avalanches have been reported recently, with one of them being a cornice failure. Solar aspects are becoming active with daytime warming and producing point releases that grow up to size 2, and in one case triggered a slab on a weak layers to size 2.5

Snowpack Summary

Recent storm snow varies across the forecast area, with the biggest accumulations near the coast. With warm temperatures the storm snow is bonding to the variety of old snow surfaces including a layer of surface hoar and facets buried on March 25th. This weakness, now down approximately 40 to 60cm has the potential for propagating over large areas. The problems seems more touchy in the northern part of the region, but has been reported throughout the northwest coastal area. Weaknesses have also been found within the recent storm snow with tests producing easy to moderate sudden results in the top 20 to 40cm. The early March facet/crust persistent weakness is now down over a metre and produces hard, sudden planar results in snowpack tests.

Problems

Loose Wet

Clear warm days may present a hazard on sun exposed slopes. Small avalanches may produce enough force to trigger deeply buried weak layers and produce large destructive avalanches.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Avoid exposure to solar aspects overhead, large avalanches may reach the end of run out zones.>Cornices become weak with daytime heating, so travel early on exposed slopes.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

The slab above the March 25th layer is still on the radar and should be treated with caution. It might be triggered by a small wind slab, or a loose wet avalanche on a solar aspect

Choose conservative lines and watch for clues of instability.>Be aware of the potential for large avalanches due to the presence of buried surface hoar.>Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Apr 7th, 2015 2:00PM