Between 50 to 80 millimetres of rain are expected in the next 24 hours.
Environment Canada is warning that flash floods and pooling water will affect the Lower Mainland and the Sea to Sky, including Squamish.
A rainfall warning has been issued for Howe Sound, Metro Vancouver, and west and central Fraser Valley.
The agency says a subtropical plume of moisture has taken aim at B.C.
Rain will blanket coastal B.C. today and tonight before easing off Friday morning.
