South Carolina will start evacuating more than a million people from its coast Wednesday as Hurricane Matthew bears down after killing three people, triggering floods and forcing thousands to flee in Haiti, the governor said.

Governor Nikki Haley said Tuesday she had declared a state of emergency. The evacuations will begin as the state gears up for Matthew, expected to hit the South Carolina coast Saturday with 100-mile (160-kilometer) per hour winds.

"We have decided that we will evacuate all coastal communities starting tomorrow," Haley told a news conference.