Hong Kong issued the highest "black" rainstorm warning after torrential rains caused flooding and submerged parts of streets, malls, and metro stations.
The Chinese special administrative region saw the highest hourly rainfall since records began 140 years ago.
The black rainstorm warning is the first such warning being issued since October 2021, reported the South China Post.
A trough of low pressure linked to the remnants of Typhoon Haikui brought heavy rain to the coastal Chinese province of Guangdong which borders Hong Kong.
Hong Kong takes precaution
All schools were shut due to "extreme conditions caused by extensive flooding and serious traffic disruption," announced the government.
Authorities asked workers to stay home as well. Videos circulating on social media showed streets turning into raging rivers.
The functioning of the country's rail network was disrupted. The Stock exchange was set to remain closed as long as the black rainstorm warning is in place.
City leader John Lee expressed his deep concern about the flooding and said that he had instructed all departments to respond with "all-out efforts."
According to authorities, rescue operations were being conducted in various flooded districts.
Authorities in China's southeastern state of Shenzhen warned Hong Kong on Thursday that water might have to be discharged from the Shenzhen reservoir, which could cause further flooding the territory's The Standard newspaper reported.
Experts blame climate change
Within the past week, Southern China witnessed two typhoons in quick succession — Saola and Haikui. Hong Kong avoided a feared direct hit.
Experts say climate change has increased the intensity of tropical storms with more rain and stronger gusts leading to flash floods and coastal damage.
Extreme conditions are expected to last in Hong Kong until Friday.
