The strongest typhoon to hit Hong Kong in 13 years swirled into southern China as a tropical storm Tuesday, still potent enough for mainland authorities to order the evacuation of tens of thousands of people and warn residents of possible flooding.

Vincente departed Hong Kong midmorning, after leaving more than 100 residents injured and paralyzing business in one of the world's leading financial centres. By early afternoon, Hong Kong airport was operating near normal, and the Hong Kong Stock Exchange had resumed trading.

On the mainland, Chinese state media said that even in its weakened condition Vincente could still dump 300 millimetres of rain in Guangxi province, after it passes through Guangdong, adjacent to Hong Kong.

They said that authorities had evacuated more than 42,000 people from the Guangdong city of Maoming, and were preparing to cope with possible "flash floods, mudslides, landslides and other disasters."

High winds in Hong Kong

Vincente made landfall near Hong Kong at 4 a.m. local time after the Hong Kong Observatory issued its No. 10 hurricane signal — the highest — for the first time since 1999.

Fallen trees block a road after the typhoon swept through Hong Kong. (Bobby Yip/Reuters)

By early Tuesday, wind speeds that had reached around 140 km/h moderated to 59 km/h and the observatory lowered its signal, though still warning the territory's residents of strong gales.

The Hong Kong government said that 118 people had been injured during the night, including 52 admitted to hospitals. Flying debris struck several people in the central business district and subway stations around the territory were converted into temporary shelters to accommodate dozens of stranded passengers.

At daybreak, the normally bustling central district resembled a ghost town, with the stock market and major banks closed and businesses shuttered.

Dozens of flights at Hong Kong airport were cancelled or delayed, and ferry services linking Hong Kong island with Kowloon, the New Territories and outlying islands were suspended.

Throughout the morning, cleanup crews struggled to remove fallen trees and branches from major roadways. Some flooding was reported in the New Territories.