Tropical Storm Podul has reached southern China, dumping more than 70mm of rain an hour on parts of the provinces of Guangdong, Hunan and Jiangxi and disrupting hospitals and law courts in Hong Kong.
The Asian financial hub issued its highest-level "black" weather warning on Thursday, adjourning the hearing of Hong Kong media tycoon and pro-democracy advocate Jimmy Lai until the torrential rain subsides, as a queue formed outside the court for the public gallery.
Medical authorities announced that out-patient clinics across Hong Kong would shut until the "black" rainstorm warning is lifted, with accident and emergency services remaining open. The postal service said it would also suspend operations due to the downpour.
Podul weakened from a typhoon to a tropical storm after making landfall in Taiwan on Wednesday, where winds of up to 118km/h left one person missing and 143 injured, but its residual vortex stands to wreak havoc in southern China, still reeling from the heaviest rains in generations last week.
China, the world's second-largest economy, faces growing threats from extreme weather, which meteorologists link to climate change. Risks that each year stand to wipe out tens of billions of dollars worth of commercial activity, as cities flood, shipping activity stalls, and croplands are washed out.
Podul made landfall on the coast of China's southeastern province of Fujian on Wednesday, and is forecast to move northwest at a speed of 22km/h, according to China's weather authority.