The Canadian Avalanche Centre has issued an avalanche warning for this weekend for several back country areas in the province. (Canadian Press)

A growing avalanche threat across most of B.C. has prompted the Canadian Avalanche Centre — for the first time ever — to issue its third special slide warning in as many weeks.

"Three warnings in three consecutive weekends is unprecedented," said Karl Klassen, the centre's avalanche bulletins manager.

"Several weak layers in the upper snow pack are proving to be very persistent and show no signs of improvement."

The result is an extreme avalanche threat with the danger of major slides, Klassen said.

He said avalanches have been getting bigger and anyone caught in them would likely have died.

The latest warning includes the North Rockies and the Columbia Mountains from Mackenzie south to the U.S. border and east of Prince George and Kamloops, as well as the South Chilcotin Mountains, north of Pemberton.

The avalanche centre warned people to stay out of avalanche terrain until the snowpack becomes more stable.

Four men have died in avalanches in B.C. since the beginning of the year.