Three people died and more than a million were without power as Hurricane Helene raged across Florida and into Georgia on Friday.

It is the strongest storm ever to hit Florida's Big Bend and is now approaching Atlanta, one of the country's largest cities.

Florida Gov. Ron DeSantis warned that more deaths were “likely” as winds reached 140 mph (225 kph) and six meters (20 feet) of rain fell on land.

On Friday, streets and houses were under water. One family described having to swim out of their home to safety. Insurers and financial institutions said damage caused by the storm could amount to billions of dollars.

Hurricane Helene weakened to a tropical storm after making landfall as a category four hurricane on Thursday evening, but authorities said it still posed a threat to life.

The hurricane is the 14th most violent to hit the United States on record. At about 420 miles wide, it falls just behind only two other hurricanes – Ida in 2017 and Opal in 1996, both of which were 460 miles wide.

Due to its sheer size, the strong winds and heavy rains have widespread impacts across Florida, Georgia and the Carolinas.

Late Thursday, Gov. DeSantis said one person died in Florida after a traffic sign fell on their car.

“You just have to hunker down now,” DeSantis said. “Now is not the time to go out.”

Two people in Wheeler County, Georgia, also died, the county coroner told the BBC's US partner, CBS News. Winds are reported to have increased and a mobile home overturned, NBC News added.

More than 1.3 million homes and businesses were without power in Florida, according to the tracking website poweroutage.us. Florida has a population of approximately 22 million people.

Another 460,000 customers in Georgia, 67,000 in South Carolina and 20,000 in North Carolina lost power, the website added.

In Pasco County, 65 people were rescued and many roads in Lee County are impassable.

Further south along the coast, hotel guests were evacuated from a Ramada Inn in Manatee County because the hotel was flooded with water.

And in Suwannee County, authorities reported “extreme destruction,” with trees falling on homes.

Michael Brennan, director of the National Hurricane Center (NHC), said damaging winds are expected to hit Georgia and the Carolinas throughout Friday, particularly over the higher terrain of the southern Appalachians.

In a speech at the White House on Thursday evening, President Joe Biden urged residents to “listen to local officials and heed evacuation warnings.”

In Taylor County, the sheriff's department required people who refused to evacuate to have their name and date of birth written in permanent ink on their arms “so they can be identified and their family notified.”

Briana Gagnier told the BBC how she and her family saw water entering their home in Holmes Beach, Florida, and began placing their belongings on tables and beds before they heard a loud bang.

“My family and I all looked at each other,” she said. “Then water just started pouring in.”

Ms Gagnier said she grabbed her pets, wallet and some portable chargers and swam out of her home with her family. The water was up to their shoulders.

The hurricane also affected the race for the White House, as Republican vice presidential candidate JD Vance canceled two events in Georgia scheduled for Thursday.

Hurricanes require sea surface temperatures greater than 27 °C (80 °F) to propel them.

Because the waters of the Gulf are exceptionally warm at 30-32 °C (86-89 °F), the sea surface is about two degrees Celsius above normal for this time of year.

Florida's 220-mile (350-kilometer) Big Bend Coast is where Hurricane Idalia made landfall in 2023. The area was also hit by Hurricane Debby last month.

The Florida Department of Emergency Management posted a list of counties where voluntary or mandatory evacuation orders were issued prior to Helene.