03/23/2012 05:16 EDT | Updated 05/23/2012 05:12 EDT

Centre warns of possibly deadly avalanche conditions in B.C.'s backcountry

VANCOUVER - The Canadian Avalanche Centre has issued its fourth special avalanche warning in five weeks after several layers of snow have come down over an unstable base.

Ilya Storm, a forecast co-ordinator for the centre, says over the past few days they've received many reports of very large avalanches.

He says many people with a lot of experience have been surprised by the avalanches, sometimes triggered from significant distances.

On Wednesday, two heli-skiers were killed when a large avalanche rolled over a group of four skiers in a mountain range in southeastern B.C.

The warning includes mountains on South Coast Inland, the North and South Columbias, the Cariboos, the Purcells, the South Rockies, the Lizard Range and the Kootenay Boundary area.

Storm says the weekend forecast calls for clear skies and sunshine and that will entice users to the backcountry, which will have a destabilizing effect on the snowpack.