Typhoon Vicente battered Hong Kong with gale-force winds and torrential rain, grounding flights and shutting port operations.
Authorities hoisted the No. 10 tropical cyclone signal for several hours overnight, making this one of the strongest typhoons to hit the city in the past decade.
Financial markets, schools, businesses and non-essential government services close when a No. 8 signal or above is hoisted, posing a disruption to business in the capitalist hub and former British colony that returned to Chinese rule in 1997.
By 8 a.m. (0000 GMT), the typhoon was veering away from the city and weakening, although the No. 8 signal is expected to remain in force until at least 10 a.m. (0200 GMT), the Hong Kong Observatory said, which would force a closure of the stock market for the morning.
The market will be closed for the day if the No. 8 signal remains in place until noon (0400 GMT). Separately, China's National Meteorological Center issued an orange alert for Typhoon Vicente, the second highest warning level in China's four-tier typhoon warning system, the official Xinhua news agency reported.
Strengthening gale-force winds overturned trees, churned up huge waves in Hong Kong's Victoria Harbour and sent debris flying, injuring some 30 people as Vicente slammed into the city and the western reaches of China's Guangdong province.
Fifteen flights were cancelled and more than 200 delayed late on Monday, aviation authorities said, although Hong Kong's main carrier Cathay Pacific said it planned to resume some flights. Affected airlines are expected to have to clear a sizeable backlog of stranded passengers.
The Hong Kong Observatory raised the No. 10 signal early on Tuesday as typhoon Vicente swept much closer to Hong Kong than initially thought, making this the first time the highest typhoon signal had been raised since 1999.
More than 30,000 Chinese fishing boats were alerted to return to harbour, with 10,560 fishermen taking shelter ashore in Guangdong, Chinese state media reported. Storm surges and sea wave warnings were heightened, with winds of up to 100 kph (60 mph) expected.