Hurricane Matthew has been downgraded to a post-tropical cyclone, but the storm is not over for the East Coast.

South Carolina recorded its first fatality related to Hurricane Matthew and its aftermath.

Gov. Nikki Haley says the victim was in a car that was swept away in Florence County.

That death brings to 15 the number of weather-related deaths in the U.S. from Matthew. Seven people died in North Carolina; three were killed in Florida. Four died in Georgia. Some were killed by falling trees, others by carbon monoxide fumes from a generator.

Haley says nearly 750,000 customers remain without power in the state, down from the peak of about 850,000.

The death toll in North Carolina more than doubled, rising from three to seven Sunday morning.

Gov. Pat McCrory also said the state faces "major destruction" in the aftermath of the storm, and he is asking the federal government for help.

Water rescues are underway not only along coastal areas, but inland as well.

The U.S. National Hurricane Center says hurricane-force wind gusts are battering North Carolina's Outer Banks, even though Matthew was downgraded from a hurricane to a post-tropical cyclone early Sunday.

The center said in its 8 a.m. ET Sunday update that the center of the storm was about 60 miles (95 kilometers) east-southeast of Cape Hatteras, North Carolina, and had maximum sustained winds of near 75 mph (120 kpm).

A hurricane watch was still in effect for parts of coastal North Carolina, including Pamlico and Albemarle sounds, for the next 6 to twelve hours.