Polls opened for early voting on Thursday in North Carolina - a critical battleground in the Nov 5 US presidential election - just weeks after Hurricane Helene left some residents still without power, running water or phone service.

North Carolina could be crucial in determining a winner in the race between US Vice President Kamala Harris, a Democrat, and Republican former President Donald Trump because its voting preferences could swing either way. Polls show a very tight race overall with a handful of swing states likely to determine the winner.

Hurricane Helene, which killed more than 200 people across six states and caused billions of dollars in damage, has sparked questions on how it might impact voter turnout.

Harvey Neal, a 71-year-old retiree, voted at the lone early voting site in Hendersonville, North Carolina, as a steady stream of voters filed in and out of the center on Thursday morning.

Neal cast his vote for Harris. "She's young, she's a Democrat," he said. "And, you know, what's the alternative?"

Neal considers himself relatively fortunate following the hurricane as nothing hit his house, though he had been without power for four or five days.

First-time voter Trevor Miller, a 21-year-old student, said he voted for Trump. "I just want to be able to live the best way possible, and I felt like with my vote that that could happen."

Trump and Harris are in a dead heat in North Carolina, with Trump showing 48% support in state polls, versus 47.5% for Harris, according to poll aggregator FiveThirtyEight.

Some of the state's hardest hit counties lean both Republican and Democratic. For instance, Buncombe County - home to the city of Asheville - supported President Joe Biden in the 2020 election versus Trump, while neighbouring Yancey County favoured Trump.

North Carolina's state elections board has spent weeks assessing storm damage to polling locations. On Thursday, 76 early voting sites were set to open to voters in the 25 western North Carolina counties listed in the federal disaster declaration. That compares to 80 planned before the storm.

Early voting has been the most popular way for North Carolinians to cast a ballot in both the 2020 and 2016 elections, according to the state. Early voting started on Tuesday in Georgia, another closely contested state that was hit by storm damage.

Still, near polling sites in western North Carolina were reminders of the destruction the region has faced, with trees uprooted and debris piled on the sides of roads. In Swannanoa, buildings still lay reduced to rubble and a house-sized chunk of the ground was caved in along a main street.

Gene Dickinson, a 75-year-old resident of Asheville, said he had been planning to vote for Trump this year but has been too busy helping run supplies to those in need since the hurricane to think about voting.

"With everything that's going on, I haven't even thought about that," he said outside of a FEMA recovery centre. "I've heard about it, but we don't have any TV or anything."

In Burnsville, Tina Veitch, a 49-year-old graphic designer, said the road to her family's house was destroyed by the storm. But one of the reasons she has stayed in the area, instead of seeking refuge with family in Florida, is so she can vote.

She said on Wednesday that the process to vote by absentee ballot was too arduous, adding: "The amount of hoops you have to jump through to just do it was not worth it ... So we were like, 'We're just going to stay 'til tomorrow at least and vote'."