Footage shows a car being swallowed up by floods, and staff at a metro station wading through waist-high water levels after a record amount of rainfall fell on Hong Kong and the Chinese border city of Shenzhen.

On Thursday night Hong Kong experienced the most rainfall in an hour since records began in 1884, with the Hong Kong Observatory recording 6.2 inches of rainfall between 11pm on Thursday and midnight.

The weather bureau issued a black rainstorm warning last night – the first in nearly two years – which remains in place until midnight on Friday.

All schools in Hong Kong have been forced to shut and authorities told workers to stay at home on Friday as the Asian financial hub’s stock exchange was also shuttered.

Videos showed cascades of water surging down steep hillsides in the former British colony, flooding waist-deep in narrow streets, and inundating malls, metro stations and tunnels.

The extreme weather also brought chaos to the nearby Chinese city of Shenzhen, a tech hub of more than 17.7 million people, with business and transport links across the economically important Pearl River Delta severely hit.

All schools, some subway stations and offices in the Guangdong city of Shenzhen were shut on Friday.

More than 100 pigs in an area near the border with Shenzhen drowned in a flood, local media reported.

A rainfall log showed 465.5mm (1.5ft) of rain fell in Shenzhen over a 12-hour period, the highest since records began in 1952.

Daily rainfall in the city in the Pearl River Delta linking Hong Kong to China’s mainland was expected to exceed 500mm, local media said.

Hong Kong’s weather bureau issued its highest “black” rainstorm warning, and said more than 200mm (7.9 inches) of rain was recorded on Hong Kong’s main island, the Kowloon district and the north-eastern part of the city’s New Territories from late on Thursday.

The city’s leader, John Lee, said he was very concerned about the severe flooding in most parts of the territory and had instructed all departments to respond with “all-out efforts”.

Hong Kong’s cross-harbour tunnel, one of main arteries connecting its island to Kowloon, was inundated and a shopping mall in the Chai Wan district was half-submerged.

Some passenger and cargo clearance operations at two border points between Hong Kong and Shenzhen were suspended due to flooding.

Macau ferry operators in Hong Kong said several sailings would be suspended to the gambling hub.

The torrential rain was brought by Haikui, a typhoon that made landfall in the Chinese province of Fujian on Tuesday.

Although it weakened to a tropical depression, its slow-moving clouds have dumped huge volumes of precipitation on areas still soaked by rain from a super typhoon a week earlier.

Additional reporting by agencies