Rainfall warning in Metro Vancouver: Heavy rain could cause ...

Environment Canada has issued a rainfall warning in Vancouver due to an atmospheric river expected to drench the B.C. coast through the weekend. 

Starting on Friday, Oct. 18, rainfall is expected to begin through the morning across the Lower Mainland, northern areas of Fraser Valley West, Howe Sound, and sections of the Sea to Sky Highway south of Whistler.

Rainfall from the atmospheric river is expected to intensify through Friday afternoon and evening with the heaviest rainfall on Saturday morning and early afternoon.

The heavy rainfall is expected to ease on Saturday night and "a second pulse of rain" is expected Sunday. 

Environment Canada says Metro Vancouver may receive 40 to 70 mm of rainfall, with higher amounts potentially exceeding 100 mm over the North Shore Mountains.

In the Sea to Sky corridor, totals of 70 to 100 mm are possible.

Drivers should brace for possible flash floods and water pooling on roads. Localized flooding in low-lying areas is possible.

Atmospheric rivers are "narrow bands of heavy precipitation" that track north and south, typically measuring 100 to 200 km in width.

Catastrophic flooding in November 2021 was caused by an atmospheric river that brought torrential rain to southern B.C. for days. However, many factors contributed to the damaging event, including high snow banks and significant rainfall before it through the fall.