REVELSTOKE, B.C. - A special avalanche warning has been posted for recreational backcountry users in several regions of B.C. and Alberta as warm temperatures make the snowpack unstable.
Avalanche Canada and Parks Canada have issued the advisory to take effect immediately and last through to Monday.
The warning applies to the North and South Columbias, Purcells, Kootenay Boundary, and Glacier, Banff, Yoho and Kootenay National Parks.
It also applies to B.C.'s Sea-to-Sky region and South Coast Inland area from Squamish to Pemberton.
James Floyer, the forecasting program supervisor for Avalanche Canada, says there are weak layers in the mountain snowpack across most of southern B.C. and western Alberta.
He says the combination of the snowpack structure, sunshine and higher temperatures will make natural and human-triggered avalanches much more likely.
The forecasting agency says there have been several close calls reported recently including one last weekend in southeastern B.C. where a large avalanche buried all but the head of a snowmobiler and his companions were able to dig him out alive.
"There is a lot of uncertainty with these weak layers,” says Floyer. "While we have targeted an area where we think there is a higher risk of triggering these deep weak layers, we also urge backcountry users in adjacent regions to exercise caution during this warming period.”