Torrential rains from Storm Helene have devastated parts of North Carolina and Tennessee – the latest southeastern US states hit by a disaster that killed at least 63 people.

In North Carolina, the mountain town of Asheville was largely cut off from the power grid by flooding on Saturday, the BBC’s US partner CBS News reported.

More than 400 roads remain closed in the state and ten people have died. According to the state’s governor, Roy Cooper, relief supplies are being airlifted to residents.

Officials continued their daring rescue operations using boats, helicopters and large vehicles to help people stranded in floodwaters – including about 50 workers and patients crowded on the roof of a flooded Tennessee hospital.

In North Carolina, many gas stations are closed and there are long lines at the gas stations that are still open. At least three million customers in five states were affected by power outages.

The storm began as a hurricane – the strongest on record to hit Florida’s Big Bend – and moved north into Georgia and the Carolinas after making landfall overnight Thursday.

In pictures: Destruction caused by Hurricane Helene

Although Helene has weakened significantly, meteorologists warn that strong winds, flooding and the threat of tornadoes could continue.

Damage is estimated at $95 billion to $110 billion (£71 billion to £82 billion). Gov. Cooper called it “one of the worst storms in modern history” to hit North Carolina.

Asheville, home to about 94,000 people and a popular tourism and arts center, was crowded and eerily quiet on Saturday, CBS reported.

The search for survivors continues and federal emergencies have been declared in six states, including Florida and Georgia.

In Tennessee, 58 patients and staff were stranded on the roof of a hospital in the town of Erwin on Friday. The fast-flowing waters of the Nolichucky River prevented boats from conducting rescue operations, and strong winds prevented helicopter operations.

The group was later brought to safety after Tennessee National Guard and Virginia State Police helicopters responded.

“The devastation we are experiencing in the wake of Hurricane Helene has been overwhelming,” President Joe Biden said Saturday.

He was briefed by Deanne Criswell, head of the Federal Emergency Management Agency, who he directed to expedite support for storm survivors, including sending additional teams to North Carolina.

There could be up to 25 named storms in 2024, the National Oceanic and Atmospheric Administration warned earlier this year.

Between eight and 13 of these storms could develop into hurricanes, and a handful, including Helene, have already done so.

Officials warned that more storms could be on the horizon, with the official end of hurricane season not until November 30.