Typhoon Rammasun is headed for China after battering the northern Philippines, where it killed at least 38 people.
Philippine officials say eight people are also missing after the storm cut a path across the main island of Luzon on Wednesday.
Hundreds of thousands are still without power in the capital, Manila, and surrounding areas, where trees and power lines remain down.
Most of those killed were hit by falling trees or other debris. In the city of Lucena, at least three people died when a wall collapsed on them.
Forecasters believe the storm will regain its category three strength as it moves over the warm waters of the South China Sea in the direction of Hainan Island, which is home to nearly 9 million people.
Rammasun, which means "God of Thunder" in Thai, is now a category one storm, with sustained winds of up to 130 kilometers per hour and gusts of up to 160 kilometers per hour.
The storm, which is moving northwest at about 25 kilometers per hour, is expected to make landfall in southern China sometime on Friday.
China's official Xinhua news agency said strong gales, downpours and high tides are expected along the country's southern coast.
It said shipping will be halted indefinitely starting Thursday morning in the strait between Hainan and China's southern Guangdong Province.
Ahead of the typhoon, Philippine authorities evacuated more than 400,000 people. This was in an effort to prevent a repeat of last November's typhoon Haiyan, which killed 6,300 people with its tsunami-like sea surges.
About 20 major storms hit the Philippines every year.