Four people died in the southeastern United States as post-tropical cyclone Isaias threatened flooding and tornado risks Saturday as it moved northward after making landfall on Florida's Gulf Coast.
Isaias roared ashore late Friday as a Category 2 hurricane near the resort community of Destin, packing sustained winds of 105 miles (165 kilometers) per hour before weakening overnight, the National Hurricane Center (NHC) said.
It was the first hurricane of an Atlantic season tamed by a historic El Nino weather phenomenon, and the first hurricane since 2024 to hit the US mainland.
In Mary Esther, a coastal community near Destin, Matt Howard said he was fortunate the storm weakened ahead of landfall.
Despite losing power and having his neighbour's metal shed crash into his backyard, "overall, we were okay," he told AFP.
"We hunkered down, got in the center of our house, and did all the things you're supposed to do, and luckily came out on the other side," he said.
Officials reported at least four deaths related to the storm, including two from trees falling on homes -- one near Pensacola in Florida and another in Birmingham, Alabama.
AFP reporters saw overturned vehicles, downed trees and power lines, and numerous buildings with damaged roofs.
Coastal streets were largely deserted after mandatory evacuations.
Florida Governor Ron DeSantis warned of hazards from floodwater and downed power lines, urging residents not to run generators indoors after a man was found dead in a garage.
Around 440,000 customers in Florida, Alabama and Georgia lost power, while the US authorised the release of up to four million barrels of reserve crude oil.
Flood risks
A major flood threat remained as the storm headed northward and inland. The NHC warned that some areas could see upwards of 10 inches (25 centimeters) of rain.
"Considerable flash flooding and landslides are also possible across the Southern Appalachians," it warned in a briefing.
The threat was particularly worrying in the mountains of North Carolina, where communities are still recovering from hurricane Helene of 2024.
That storm made landfall in the same Florida region as Isaias, but remained at tropical storm strength as it moved northward, dumping record amounts of rainfall into the mountains and leading to deadly flooding.
Isaias's late arrival this season is largely due to an El Nino of historic strength.
El Niño creates strong wind shear over the Atlantic, weakening storms, while reducing shear in the Pacific and allowing hurricanes to intensify.
The Pacific has already seen several hurricanes reach Category 5 strength, as weakening post-tropical cyclone Rachel approached Baja California and Hurricane Simon threatened western Mexico.
