At least 30 people have been killed as Hurricane Helene barrelled its way across southeastern US.
Emergency crews are racing to rescue people trapped in flooded homes after Helene struck the coast of Florida overnight as a highly destructive Category 4 storm.
It generated a massive storm surge and knocked out power to millions of customers in Florida and neighbouring states.
It struck with maximum sustained winds of 140 mph (225 kph) in the rural Big Bend area, the northwestern part of Florida.
The National Hurricane Center said preliminary information shows water levels reached more than 15ft above ground in that region – but the damage has extended hundreds of miles north.
Helene, which has now been downgraded to a tropical storm, is now over North Carolina with maximum sustained winds of 45mph (72kph).
US President Joe Biden approved emergency declaration requests from the governors of several southern states affected by Helene.
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Georgia, Florida, Alabama, North Carolina and South Carolina will receive help from more than 1,500 emergency response personnel including search and rescue teams, medical support staff and engineering experts.
Georgia Governor Brian Kemp has said dozens of people are still trapped in buildings damaged by the storm.
Meanwhile, Florida Governor Ron DeSantis said the damage from Helene in the area appears to be greater than the combined damage of Idalia and Hurricane Debby in August. “It’s demoralizing,” he said.
Many stranded in places like Tampa could only be reached by boat, with officials warning the water could contain live wires, sewage, sharp objects and other debris.
More than four million properties are without power across Florida, Georgia and the Carolinas according to the logging website, PowerOutage.
Science and technology editor
Despite Helene’s power, this hurricane season has been more remarkable for its lack of activity.
At the start of the hurricane season, which runs from June 1st to November 30th, sea surface temperatures were (and remain) off-the-charts warm.
It’s this ocean heat that fuels tropical storms.
This combined with a developing La Nina phenomenon led the US forecasters to predict 2024 would be a major hurricane season. Between 17 and 24 storms were expected, with 8 to 13 developing into hurricanes.
Hurricane Beryl grazed the coast of Jamaica in July as a Category 5 hurricane. It was the earliest storm of that size ever recorded and was seen as a harbinger of the prediction. But, so far at least, it’s failed to materialise.
There have been just 6 hurricanes so far this year – slightly below average. But why?
It seems to be due to what’s happening on the other side of the Atlantic where ocean warming forced the African monsoon further north than usual.
This led to catastrophic flooding in central and west Africa displacing millions, but it also shifted the weather system that usually spawns hurricanes and spins them across the Atlantic.
There’s already abundant evidence our warming oceans and atmosphere are making storms more intense – but predicting where they will occur and how often is never simple – and perhaps getting even harder as our planet gets hotter.
Prior to the hurricane making landfall, officials in Florida begged residents to evacuate. The sheriff’s office in rural Taylor County issued a chilling warning to those who refused to leave.
“Please write your name, birthday, and important information on your arm or leg in a permanent marker so that you can be identified and family notified,” the post on Facebook said.
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Forecasters now expect the storm to continue weakening as it moves into Tennessee and Kentucky.
But it could drop heavy rain over the Appalachian Mountains, with the risk of mudslides and flash flooding.