Wind and rainfall warnings, ferry sailings cancelled as storm moves over B.C. coast

A large storm system passing through coastal British Columbia has already caused power outages, forced ferry cancellations and prompted wind and rainfall warnings from Environment Canada, as well as high streamflow advisories.

A "bomb cyclone" — a low-pressure system that brings rain and powerful winds — hit offshore close to Vancouver Island on Sunday, according to Environment Canada, bringing concerns for potential power outages and flooding over the next few days.

On Monday, a rainfall warning for Howe Sound said up to 65 millimetres of rain could fall in the area.

Gusts as strong as 110 km/h could blast the east coast of Haida Gwaii, while the east coast of Vancouver Island, including the Greater Victoria area is expected to see gusts up to 90 km/h close to the water on Monday morning, Environment Canada said.

Coastal areas of Metro Vancouver could experience gusts up to 70 km/h, the agency warned.

It says the high winds could cause power outages and fallen tree branches, and loose objects could be tossed, causing injury or damage.

B.C. Hydro's website shows wind had knocked out power in dozens of spots along the Sunshine Coast and Vancouver Island by noon Monday.

Early Monday, B.C. Ferries announced the cancellations of some sailings, including several on the busy Tsawwassen-Swartz Bay route, due to windy conditions.

Hullo Ferries, which provides walk-on service between Nanaimo and Vancouver, has also cancelled sailings in both directions.

Environment Canada also said more than 50 millimetres of rain is forecast to hit western parts of Vancouver Island by Tuesday, while Metro Vancouver and other parts of the South Coast will get closer to 30 millimetres.

The forecast has prompted the provincial River Forecast Centre to issue a high streamflow advisory for Vancouver Island, the Sunshine Coast, Howe Sound and the Lower Mainland.

Possibility of falling trees, power outages

The hot, dry summer B.C. has experienced has also made it more vulnerable to storm damage.

Alyssa Charbonneau, a meteorologist with Environment Canada, said there is particular danger for trees breaking and falling as they have been made brittle by the lack of water.

"Even with more modest wind gusts, we could see some more impacts than what we'd normally expect," she said.

B.C. Hydro said in a statement about half of all power outages are caused by fallen trees.

Drought and wildfire exacerbate one another, leaving soil not only parched but also much less absorbent to water when it does fall, said Daniel Sharp, an arborist with Davey Tree Service in Vancouver.

They also damage vegetation and trees, making root systems less stable and trees more likely to fall over or be washed away, he added.

"The reduction in plant matter is going to mean that the water that comes down … those hillsides are going to have nothing to absorb it," said Sharp. "That's when you potentially see things like landslides and flooding in those recently burned areas."

Trees that fall can also down power lines and cause widespread outages, said Sharp, or accumulate and block water drainage, making flooding worse.

Vulnerability to flooding

B.C. residents should be prepared for high winds and fallen trees to cause potential power outages, and make sure they have spare batteries, candles, non perishable food and clean water to hand, said Brent Ward, co-director of Simon Fraser University's Centre for Natural Hazard Studies.

While rain is welcome amid historic drought conditions and wildfires across B.C., Environment Canada says there won't be enough in the north and Interior to completely douse wildfires.

And experts say the heavy rainfall carries flooding risks for already damaged ecosystems on Vancouver Island and across the South Coast.

Ward said B.C. could see localized flooding in some areas, particularly on Metro Vancouver's North Shore in areas like Mosquito Creek and McKay Creek — where water levels can rise quite quickly.

"Because we haven't had a lot of rain in a long time, some culverts might plug around roadways," said Ward. "So you could easily see pooling water on the road surface, which is always a concern."

"I don't think we're going to have enough water to actually trigger landslides. So that's good news," he added.

Storm could help fish, fires

He also said the rain is good news for fish whose spawning cycles have been disrupted by lower water levels this past summer.

Meanwhile, British Columbia's northern Interior, where most of the current wildfires are burning, remains dry and smoky.

Charbonneau said some moisture from the coastal weather system will push into the Interior, but it won't be as widespread.

"Every bit helps,'' she said of rain in the fire zones. "We're not expecting the strong winds though, so that's a positive.''