Forecasters warn heavy rain is expected to sweep across B.C.’s south coast Friday, in some areas dumping twice the average monthly amount of rain in just one day.
Environment and Climate Change Canada (ECCC) issued a rainfall warning for Friday for much of Metro Vancouver, the Sunshine Coast and Howe Sound, where between 50 and 80 millimeters of rain is expected. The warning was later extended to include the Fraser Valley, including Abbotsford.
It said a moisture-laden frontal system will bring rain and strong southerly winds to the south coast Friday morning.
A cold front is expected to arrive later in the day, bringing the heaviest rainfall rates during the afternoon commute. ECCC warns there could be poor visibility on the roads and an increased risk of hydroplaning. While local flooding is possible.
Environment Canada meteorologist Christy Climenhaga said Vancouver typically sees close to 36-millimetres for the entire month of August.
“This is unseasonable for this time of year to see this much rain in a short period of time,” she said.
She said the west part of Vancouver Island could also see between 50-75 millimetres of rain, while the east coast of the island can expect 10 to 20 millimetres.
The B.C. River Forecast Centre issued a high streamflow advisory for the South Coast and North Shore Mountains, saying rivers are expected to rise rapidly on Friday.
The centre said streamflow is already high in rivers fed by glaciers due to recent warm weather, and could become more hazardous because of the forecast rainfall.
Rain is expected to taper off in the south coast through the weekend, with temperatures climbing back to a more seasonal range next week.
Sarah Budd, provincial information officer for the B.C. Wildfire Service, said the rainfall will help firefighters battling wildfires in that part of the province, including the out-of-control Underwood fire. But she said it likely won’t be enough to address the severe dryness and underlying drought conditions fueling the fires.
She compared the landscape to a dry sponge sitting by a kitchen sink.
“You really have to submerge the sponge to get it to absorb the water,” said Budd. “We would need a more prolonged and consistent bout of rain to change the fire weather indices in that area.”
The Underwood fire south of Port Alberni had grown to more than 34-square kilometres as of Thursday and has prompted multiple evacuation orders and alerts for nearby properties.
