Another powerful storm is headed for B.C.'s South Coast, triggering rainfall warnings in Metro Vancouver, the Fraser Valley and parts of Vancouver Island.

Environment Canada is forecasting heavy rain will start pouring Wednesday evening and Thursday as a "moisture-laden frontal wave" reaches the region.

Up to 90 millimetres of rainfall is expected in some areas of the mainland through Thursday night, and Environment Canada cautions there could be more localized flooding.

"Heavy downpours can cause flash floods and water pooling on roads," the weather agency said in a warning. "If visibility is reduced while driving, turn on your lights and maintain a safe following distance. Watch for possible washouts near rivers, creeks and culverts."

People in Vancouver, Burnaby, New Westminster, Coquitlam, Maple Ridge, West Vancouver, North Vancouver and Abbotsford are all being told to be extra careful on the roads.

On Vancouver Island, Environment Canada is forecasting up to 50 millimetres of rainfall between Qualicum Beach and Fanny Bay Wednesday, though the frontal wave is expected to depart overnight.

Snow is possible further inland, including along the Coquihalla Highway between Hope and Merritt. A snowfall warning issued Wednesday suggests as much as 40 centimetres could fall by the time the storm has passed.

The snow is expected to start Wednesday and intensify overnight, easing late Thursday evening. The warning is in effect for the Boundary, East and West Columbia, Fraser Valley, Fraser Canyon, Kootenay Lake, Nicola, Shuswap and West Kootenay regions of B.C.

The storm comes a day after another downpour caused issues across Metro Vancouver, washing out busy streets and flooding a SkyTrain station along TransLink’s Expo Line.

Buildings in parts of Vancouver also suffered flood damage, and BC Ferries was forced to cancel a morning sailing from Tsawwassen to Victoria.

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