Category 2 Hurricane Isaias has made landfall near Destin, Florida, the US National Hurricane Center said in its latest advisory.
"Isaias makes landfall near Destin, Florida," the National Hurricane Center's latest update said late on Friday.
"Life threatening storm surge impacting Gulf coast as dangerous hurricane conditions and flash flooding spread inland."
The hurricane, packing maximum sustained winds of 165 kph, is about 80 km west-northwest of Panama City, Florida, the centre added.
Isaias is the first hurricane of an Atlantic season that kicked off in June, held in check by a historic El Nino phenomenon that typically spurs more major storms in the Pacific.
Fuelled by record-warm Gulf waters heated by climate crisis, it underwent rapid intensification, and is set to become the first hurricane to strike the US mainland since Milton in 2024.
Trump cancels visit
Forecasters expect Isaias to slam into the western Florida panhandle at or near major hurricane strength before weakening over land.
President Donald Trump cancelled his visit to Saturday's college football game between the University of Georgia and the University of Alabama in Tuscaloosa, Alabama because of Hurricane Isaias.
Mandatory evacuation orders are in effect in several Florida counties, but impacts are expected across a swathe of the southeastern United States, with hurricane-force winds up to 160 kilometres inland.
Storm surge combined with the tide is expected to flood normally dry areas, with the NHC warning that water could reach as high as nine feet around the Alabama-Florida border.
Heavy rainfall could trigger flash flooding and push rivers over their banks.
Two airports in northwestern Florida have suspended operations.
Isaias has disrupted oil and gas production in the Gulf of Mexico, with platforms and rigs evacuated.
As of Friday, about 71 percent of the region's oil production had been temporarily halted, taking nearly 1.5 million barrels a day off the market, according to the Marine Minerals Administration (MMA).
About 59 percent of gas production was also suspended.
More than 400,000 customers in Florida and Alabama were without power Friday evening, according to poweroutage.com.
Residents in Panama City, Florida, braved the rain while filling sandbags Friday to protect their houses.
"I mean, it’s just the nature of the beast. It’s Florida," said Corliss Stone, who works for the fire department.
