Calgary, Alberta - British Columbia is rolling out the big guns - literally - to control avalanches that are forcing closures on some major roads for the first time in decades as the Western Canadian province grapples with a snowier-than-usual winter.

B.C. was rocked in 2021 by extreme weather events, including a record-breaking heatwave, wildfires and unprecedented rains that washed out highways and cut off Vancouver, its main city and home to Canada's busiest port, from the rest of the country.

The province, Canada's third-largest by population, uses bombs thrown from helicopters, remote-triggered explosives, and a howitzer gun manned by Canada's military to keep roads safe. But frequent closures for avalanche control are disrupting critical routes to Vancouver.

At the start of this month, B.C.'s alpine snowpack was 15% higher than average, according to the Weather Network channel.

Extreme winter weather, including November's torrential precipitation, a deep freeze in late December and an early January thaw, has created weak layers in the snowpack, making steep mountain slopes more prone to avalanches that can release without warning onto valleys below.

"It's been such a volatile fall and winter season so far, we have had rare 'extreme' avalanche warnings go out for parts of (B.C.'s) south coast in December and the risk is still considerable in the interior," said Tyler Hamilton, a Weather Network meteorologist.

Avalanche control missions involve closing sections of highways while teams use explosives to pre-emptively trigger smaller slides, preventing the snowpack from becoming too deep and unstable.

This winter a section of Highway 1 through the Fraser Canyon, 150 km (93 miles) northeast of Vancouver, needed avalanche control for the first time in 25 years, B.C.'s Ministry of Transportation and Infrastructure said.

Along Highway 99 north of Vancouver, avalanche control and risk-reduction activities are three times the seasonal average, with some slide paths producing avalanches big enough to hit the highway for the first time in more than a decade.

Avalanche control in Allison Pass further south on Highway 3, another key route connecting Vancouver to the rest of Canada, has also been above average, the ministry said.

Avalanche control is typically needed until late April or early May, depending on the snowpack, and the Weather Network forecasts above average winter storm systems returning to B.C. in February and March.

"We're still in a La Niña situation," said the Weather Network's Hamilton, referring to a weather pattern that tends to result in above-average precipitation and cold temperatures in B.C.
-Reuters