Hurricane Dorian has caused extensive flooding as it howled over low-lying islands off North Carolina.

With winds down to 90mph, the category one hurricane lashed homes and businesses with wind, rain and floodwaters as the storm’s centre passed just off the islands.

The Coast Guard began landing local law enforcement officers on Ocracoke Island via helicopter and airlifting out the sick, the elderly or others in distress, Hyde County authorities said.

Residents were told to get to the highest point in their homes in the meantime as they waited to be rescued.

“It’s bad,” Ann Warner, who owns Howard’s Pub on the island, said by telephone.

“The water came up to the inside of our bottom floor, which has never had water.”

Hurricane damage
A tornado spun off from Dorian left devastation in its wake in a trailer park on Emerald Isle, North Carolina (Julia Wall/AP)

“We’re safe,” Ms Warner added. “But it’s certainly a mess.”

Another Ocracoke Island resident, bookshop owner Leslie Lanier, texted: “We are flooding like crazy. It is in the houses, and there will be more before it stops.”

“Lots of people are getting water starting in their homes,” Ms Lanier added. “I have been here 32 years and not seen this.”

Hurricane damage
Kayak was the best way to travel down a road in flood waters that hit Charleston, South Carolina (Meg Kinnard/AP)

“There is significant concern about hundreds of people trapped on Ocracoke Island,” governor Roy Cooper said.

Even in good weather, the island is reachable only by boat or air.

Dorian is expected to remain a hurricane as it sweeps up the Eastern Seaboard, far enough offshore that its hurricane-force winds are unlikely to reach land.

More than 370,000 people were without electricity in the Carolinas and Virginia as Dorian moved up the coast.

At least four people were killed in the south east. All were men in Florida or North Carolina who died in falls or by electrocution while trimming trees, putting up storm shutters or otherwise getting ready for the hurricane.

On the Outer Banks, forecasters said large and destructive waves could reach nearly to the ceilings of one-story structures along the 200-mile string of islands.

“Do not let your guard down,” Dare County emergency managers warned people who insisted on riding out the storm.

Hurricane damage
Dorian left mass devastation in its wake in the Bahamas (Ramon Espinosa/AP)

As Dorian closed in, many people on the Outer Banks tied down their boats, removed objects from their yards that could blow away, and hunkered down. Ms Warner said about half the 1,000 residents of Ocracoke stuck it out.

At the start of the week, Dorian slammed the Bahamas with 185mph winds, killing at least 30 people and obliterating countless homes.

From there, it swept past Florida and Georgia at a relatively safe distance, then sideswiped the Carolinas on Thursday, spinning off tornadoes that peeled away roofs and flipped recreational vehicles.

Still, the damage was far less than feared in many parts of the Carolinas, including historic Charleston, South Carolina, which is prone to flooding even from ordinary storms, and Wilmington, North Carolina, the state’s biggest coastal city.

“We prepared for the worst and that didn’t happen. That’s OK. I was a little worried back when it was a category three. We got lucky,” said Ross Page, who walked his dogs in downtown Wilmington on Friday morning.

Joseph Pawlick went out to rake leaves, twigs and other debris blown from the pavement outside his downtown Wilmington home. “I slept like a baby last night. This, thankfully, was not bad,” he said.