Environment Canada issued a rainfall warning for Metro Vancouver and the Fraser Valley Saturday morning, noting that the heaviest rain was expected in the late afternoon and evening.

Rainfall totalling as much as 50 millimetres was expected, according to the federal agency, which also warned about the possibility of heavy downpours causing flash floods and water pooling on roads.

In Vancouver, extra crews were called in to help clear catch basins and monitor "priority locations" in preparation for heavy rainfall.

"We are prepared to activate the Departmental Operations Centre in the event of heavy rainfall resulting in flooding," the city said in a statement to CTV News Vancouver.

"If residents encounter non-emergency flooding on city streets and sidewalks, fallen tree branches or other issues, they can report it via the VanConnect app or online at vancouver.ca/vanconnect," the city said. "If there is an immediate safety issue, residents should please call 311. The city uses resident reports to help inform where response is needed and allow our crews to address issues quickly."

Environment Canada's forecast called for rain to "taper to showers overnight."

"Sunday will remain unsettled with showers and a risk of thunderstorms," the agency said in its rainfall warning.