Hurricane Helene has made landfall in Florida’s Big Bend region as one of the most powerful storms to hit the state, raising fears of deaths, widespread damage and even worse floods than the severe deluge that preceded its arrival.

Helene hit Florida packing sustained winds of about 210 km/h, the US National Hurricane Centres aid late on Thursday (local time), making it a powerful category four storm.

Even before it made landfall, the storm had flooded the Gulf Coast and knocked out power for at least one million customers in the state.

Officials pleaded with residents in the path of the storm to heed mandatory evacuation orders or face life-threatening conditions.

Helene’s surge – the wall of seawater pushed on land by hurricane-force winds – could rise to as much as six metres in some spots, as tall as a two-storey house, centre’s director Michael Brennan said in a video briefing.

“A really unsurvivable scenario is going to play out” in the coastal area, Brennan said, with water capable of destroying buildings and carrying cars pushing inland.

Strong rain bands were whipping parts of coastal Florida, and rainfall had already lashed Georgia, South Carolina, central and western North Carolina and portions of Tennessee. Atlanta, hundreds of kilometres north of Florida’s Big Bend, was under a tropical storm warning.

Florida Governor Ron DeSantis said late on Thursday the hurricane had already caused one fatality. He gave no details.

In Pinellas County, which is on a peninsula surrounded by Tampa Bay and the Gulf of Mexico, roads were already filling with water before noon.

Officials warned the storm’s impact could be as severe as last year’s Hurricane Idalia, which flooded 1500 homes in the low-lying coastal county.

Videos posted on the county’s social media site showed some swamped beachside roads and water rising over boat docks.

Airports in Tampa, Tallahassee and St Petersburg all suspended operations on Thursday.

Helene is expected to remain a full-fledged hurricane as it rolls through the Macon, Georgia, area on Friday, forecasters said.

It could bring 30 centimetres or more of rain, potentially devastating the state’s cotton and pecan crops, which are in the middle of harvesting season.

“The current forecast for Hurricane Helene suggests this storm will impact every part of our state,” Georgia Governor Brian Kemp said.

11:20pm EDT 26th September — #Hurricane #Helene has made landfall in the Florida Big Bend region at around 11:10pm EDT just E of the mouth of the Aucilla
River.

Max sustained winds at landfall were estimated at 140 mph & a min pressure of 938 mb.

Info: https://t.co/1OTHyJkqja pic.twitter.com/WWohcTqpBa

— National Hurricane Center (@NHC_Atlantic) September 27, 2024

After making landfall across the Florida coast, Helene was expected move more slowly over the Tennessee Valley on Friday and Saturday, the NHC said.

Storm surge was forecast to reach up to six metres in the Big Bend area of Florida’s Panhandle region where the storm came ashore.

Numerous evacuations were ordered along Florida’s Gulf Coast, including Sarasota and Charlotte counties.

In Taylor County, the Sheriff’s Department asked residents who decided not to evacuate to write their names and dates of birth on their arms in ink – so that they could be identified if they were later found dead.