A large storm system is heading toward the British Columbia coast on Sunday, prompting high flow advisories, wind warnings and concerns about possible power outages and flooding in the coming days.
A bomb cyclone, a low-pressure system bringing rain and powerful winds, is expected to hit the coast near Vancouver Island and continue into Sunday afternoon, according to Environment Canada.
Environment Canada forecasts more than 50 millimeters of rain will hit western parts of Vancouver Island on Tuesday, while Metro Vancouver and other parts of the south coast will approach 30 millimeters.
The forecast has led the Provincial River Forecast Center to issue a high flow warning for Vancouver Island, Sunshine Coast, Howe Sound and the Lower Mainland.
The River Forecast Center has issued a high flow advisory for Vancouver Island and the surrounding area. the south coast, including Metro #Vancouver. The public is advised to stay away from these rivers and fast-flowing waters. potentially unstable banks. More information: https://t.co/7YeiASzcOw #BCFlood #yvr pic.twitter.com/xJ8LUoBX7N
But experts say BC is not likely to experience flooding as devastating as the atmospheric river that submerged parts of Abbotsford and washed away roads in November 2021.
“It will be primarily a wind event with this storm and [it] “It will also bring some rain, but not a rain warning level,” said Louis Kohanyi, a meteorologist with Environment and Climate Change Canada.
“We’re seeing winds gusting to 80 to 100 kilometers per hour, and there will be even more wind on North Vancouver Island.”
The forecaster issued a wind warning for parts of the Sunshine Coast and the northern, eastern and western parts of Vancouver Island on Sunday.
A special weather statement also warns of strong winds on the island’s southern tip, and Environment Canada says the “significant fall storm” means it will still be windy on Monday.
British Columbia residents should be prepared for high winds and downed trees that could cause power outages, with spare batteries, candles, non-perishable food and clean water, said Brent Ward, co-director of the Center for Natural Hazards Studies at Simon Fraser University.
Some vulnerability to flooding
While the rain is welcome amid historic drought and wildfire conditions in British Columbia, Environment Canada says there won’t be enough in the north and inland to completely put out the wildfires.
And experts say the heavy rains carry flooding risks for already damaged ecosystems on Vancouver Island and along the south coast.
Ward said BC could see localized flooding in some areas, particularly on the north coast of Metro Vancouver 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 could get clogged around the roads,” Ward said. “So you could easily see standing water on the road surface, which is always a concern.”
“I don’t think we’re going to have enough water to cause landslides. So that’s good news,” he added.
Drought and wildfires exacerbate each other, leaving the soil not only parched but also much less absorbent to water when it falls, said Daniel Sharpe, an arborist at Davey Tree Service in Vancouver.
They also damage vegetation and trees, making root systems less stable and trees more likely to fall or be blown away, he added.
“The reduction in plant matter will mean that the water coming down…those slopes won’t have anything to absorb it,” Sharpe said. “That’s when you potentially see things like landslides and flooding in recently burned areas.”
Falling trees can also down power lines and cause widespread outages, Sharpe said, or pile up and block water drainage, making flooding worse.
BC Hydro said in a statement that about half of all power outages are caused by downed trees, and it’s on the lookout for more this weekend.
But Ward says the rain is good news, especially for fish whose spawning cycles have been disrupted by lower water levels in several rivers and lakes this past summer.