Hurricane Hermine has torn a path of destruction across Florida, leaving more than 250,000 homes and businesses without power, flooding low-lying areas and raising concerns over the spread of the Zika virus.
The first hurricane to make landfall in Florida since Wilma more than a decade ago, Hermine came ashore early on Friday near St Marks, Florida, 30km south of the capital of Tallahassee, packing winds of 130km/h and churning up a devastating storm surge in coastal areas.
It was set to snarl US Labour Day holiday travel after battering Florida's US$89-billion tourism industry.
The tempest headed toward the Atlantic seaboard on a path where tens of millions of Americans live, causing storm watches and warnings stretching to New Jersey, the National Hurricane Centre (NHC) said.
One homeless man was hit by a tree and died, Florida Governor Rick Scott said, but officials have not confirmed whether the death was storm-related.
"Now is the time to come together. There is a lot of work to do," Scott told a news conference, warning people to look out for downed power lines and avoid driving in pools of standing water.
Concerns over the standing water in which mosquitoes breed intensified as the state battles an outbreak of the Zika virus.
"It is incredibly important that everyone does their part to combat the Zika virus by dumping standing water, no matter how small. Any amount of standing water can serve as a breeding ground for mosquitoes," Scott said.
According to the Florida Department of Health, there have been 47 cases of Zika in people believed to have contracted the virus through local mosquitoes.
As the sun rose on Friday morning on Hudson Beach, just north of Tampa, cars sat askew in the middle of flooded out roads. Palm fronds, tree branches and garbage cans were scattered about.
Overnight, Pasco County crews rescued more than a dozen people and brought them to shelters after their homes were flooded.
A weakening Hermine moved across southern Georgia, blowing winds of 95km/h on Friday morning. The tropical storm was expected to reach the coastal Carolinas later on Friday, then move offshore from North Carolina on Saturday.
Officials in the affected region on Friday warned that homes continued to be threatened by high water and implored people to avoid flooded roads.
On its current path, the storm could dump as much as 38cm of rain on coastal Georgia, and the Carolinas. Forecasters warned of "life-threatening" floods and flash floods.
The governors of Georgia and North Carolina declared emergencies in affected regions.