Environment and Climate Change Canada has issued a rainfall warning for Metro Vancouver as an atmospheric river system arriving Friday is set to drench southwest British Columbia.
The warning said heavy rain is expected to continue into Saturday. Storm totals of 40-70 millimetres are expected in Metro Vancouver and near the mountains of the western Fraser Valley, according to the weather agency.
The North Shore Mountains could potentially get about 100 millimetres of rain and 70-100 millimetres are possible in the Sea-to-Sky corridor.
Environment Canada has also issued alerts for the Coquihalla Highway from Hope to Merritt and the Sea-to-Sky Highway from Squamish to Whistler.
The weather agency is warning of water pooling on the roads, swollen rivers and creeks, increased risk of washouts, rockfall and landslides, as well as possible power outages from tree damage due to strong winds.
The River Forecast Centre has placed the South Coast, Central Coast, Vancouver Island and Lower Fraser tributaries under a flood watch, with high streamflow advisories for the North Coast and Interior mountains.
It’s a term that became more widely known after record-setting flooding hit B.C. in November 2021, but as meteorologist Johanna Wagstaffe explains, atmospheric rivers are not new to west coast of North America.
Environment Canada said rain will begin Friday morning and intensify through the afternoon and evening, with the heaviest rain expected Saturday morning and early afternoon.
Rain should ease Saturday evening, but it said a second pulse of rain is expected Sunday.