At least eight people were killed and six people missing after one of the heaviest rain storms in 80 years hit Seoul, flooding streets and subway stations and causing blackouts.

President Yoon Suk-yeol convened an emergency meeting at the country’s National Disaster and Safety Status Control Center Tuesday after the storm dumped as much as 141 millimeters (5.5 inches) of water an hour in parts of South Korea’s capital. Three of the eight victims drowned as their basement apartment filled with water, Yonhap News Agency reported. Local television showed drivers abandoning their cars in the upscale Gangnam district and residents wading in knee-high waters.

Another 300 to 350 millimeters of rain is forecast to fall through Thursday, the Meteorological Administration said, adding to risks of more flooding.