Typhoon Ragasa has made landfall in southern China, where nearly two million people have been evacuated in preparation for its arrival.
It comes after authorities said at least 17 people had been killed and more missing in Taiwan after a lake burst on Tuesday, causing severe flooding in the island's east.
Ragasa was downgraded from a super to a severe typhoon on Wednesday but remains highly destructive, with top winds of 241km/h (150mph) recorded in Taishan county in China's south-eastern Guangdong province.
The equivalent of a Category 5 hurricane, Ragasa is the world's strongest storm this year and has been roaring over the South China Sea for days.
Ahead of making landfall, 90 people were injured in Hong Kong as the storm skirted its coastline, the hospital authority said.
The typhoon made landfall on the coast of Hailing Island, Yanjiang City in Guangdong at about 17:00 local time (9:00 GMT) on Wednesday, according to Chinese state media.
It crossed the mainland with sustained winds of 144km/h and higher gusts. Wind speeds are expected to gradually weaken as the storm moves westwards over land, but rain will be torrential and slow-moving across the region for several more days.
The southern Chinese cities of Zhuhai, Shenzhen, and Guangzhou - all located in Guangdong - were braced for seawater intrusion from about midday local time.
In Zhuhai, police patrolled the streets with sirens and megaphones, telling people to stay at home. Red alerts for landslides were also issued in the mountainous regions of Guangdong province.
Away from the Chinese mainland, authorities in Taiwan are still dealing with the destruction caused by Ragasa, which officials have described as far worse than anticipated.
Premier Cho Jung-Tai has demanded an inquiry into how evacuations were carried out after at least 17 people died after a barrier lake, formed by a landslide in July, burst its banks in Hualien county, causing severe flooding in the town of Guangfu. Others remain missing, the fire department said.
Select community leaders in Taiwan emphasize the severity of the situation in indigenous areas as reports indicate that entire villages have been flooded.
Some geologists described the breach as a tsunami from the mountains, releasing 15.4 million tonnes of water due to the dam burst. The flooding has caused extensive damage, trapping residents and hindering rescue operations.
The government has established a front-line disaster response centre in Hualien, deploying troops to assist with rescue efforts amid widespread devastation.
Typhoon Ragasa has also caused disruption in Hong Kong and the Philippines. Even though the typhoon did not make landfall in Hong Kong, powerful winds and heavy rain led to injuries and disruptions that included suspended flights and services.
With one of the most powerful trajectories seen this year, Typhoon Ragasa's impact will be long-lasting, necessitating comprehensive recovery efforts across the affected regions.
