Packing maximum sustained winds of 245km/h near its eye, Yagi registers as the world's second-most powerful tropical cyclone in 2024 so far, after the Category 5 Atlantic hurricane Beryl.
More than doubling in strength since devastating northern Philippines earlier this week, Yagi is expected to make landfall along China's coast from Wenchang in Hainan to Leizhou, Guangdong from Friday afternoon.
Winds and rain were accompanied by powerful thunder and lightening across the region overnight and on Friday morning.
Rescuers rest after a landslide caused by Tropical Storm Yagi, which hit the Philippines earlier. (AP PHOTO)
Transport links across southern China were mostly shuttered on Friday with many flights cancelled in Hainan, Guangdong, Hong Kong and Macau. The world's longest sea crossing, the main bridge linking Hong Kong with Macau and Zhuhai in Guangdong, was also closed.
In the financial hub of Hong Kong, the stock exchange was shuttered while schools remained closed.
The typhoon 8 signal, the third-highest, would be in place until at least 12pm on Friday, Hong Kong's observatory said, meaning many businesses would remain shut and transport will be significantly reduced.
"Intense rainbands associated with Yagi will bring heavy squally showers to the territory," it said, warning residents to stay away from the shoreline.
China's government sent task forces to Guangdong and Hainan to guide flood and typhoon prevention, official news agency Xinhua said.
Super Typhoon Yagi's projected landfall in Hainan is rare, as most typhoons landing on the duty-free island are classified as weak. From 1949 to 2023, 106 typhoons landed in Hainan but only nine were classified as super typhoons.
Typhoons are becoming stronger, fuelled by warmer oceans, amid climate change, scientists say. Last week, Typhoon Shanshan slammed into southwestern Japan, the strongest storm to hit the country in decades.
Yagi, which strengthened into a super typhoon on Wednesday night, is the Japanese word for goat and for the constellation of Capricornus, a mythical creature that is half goat, half fish.
