Two dead as tropical storm lashes Florida

Hurricane Nicole has weakened into a tropical storm after making landfall on Florida's east coast, still carrying a powerful punch with a mix of heavy rains and fierce winds that downed power lines, flooded homes and left at least two people dead.

As many as 350,000 homes and businesses across Florida were without power on Thursday after the storm, packing 120km/h winds, made landfall at 3am EST along the east coast north of Miami as a hurricane, the National Hurricane Center said.

Officials said two people died on Thursday after coming into contact with a wind-downed power line.

About 17,000 utility workers were staged across the state to restore electricity once the storm was over.

The year's eighth Atlantic hurricane and its 14th named cyclone system, Nicole was downgraded to a tropical storm soon after moving inland.

"We're ready and resources are available for the post-storm needs," Florida Governor Ron DeSantis said at a press conference.

"This is still a large storm and it is impacting much of the state. Winds are the main concern with Nicole."

Several beachfront homes collapsed in the upscale community of Wilbur-by-the-Sea, south of Daytona Beach, and several more were left teetering on the brink after surging waves of kicked up by high winds undercut the buildings' foundations.

Volusia and Indian River counties were among several east coast areas hard hit six weeks ago by Hurricane Ian, a catastrophic category four storm that initially struck Florida's Gulf Coast, then swept across the state to the Atlantic, causing some $US60 billion ($A92 billion) in damage and killing more than 140 people.

Kevin Guthrie, Florida's emergency management director, cautioned residents on Thursday to remain indoors, even if the eye of Nicole had passed.

"There are heavy winds and a potential for tornadoes," he said.

Wind gusts clocked at 161km/h at the Kennedy Space Center in Cape Canaveral, about 129km north of Vero Beach, buffeted a new $US4 billion ($A6.1 billion) moon rocket NASA left moored to its launchpad to ride out the storm.

NASA said early inspections showed the spacecraft sustained only minor damage such as loosened caulk and torn weather coverings.

By evening, Nicole had veered to the northwest as it churned over central and northern Florida toward the panhandle on the Gulf Coast, with maximum sustained winds clocked at 65km/h, mainly over the Gulf of Mexico, the National Hurricane Center reported.

Nicole was expected to weaken into a tropical depression Thursday night and dissipate further while remnants of the storm move through Georgia and into the Carolinas in the next two days, bringing heavy rains along the way.

State officials have opened 15 emergency shelters across the region and activated 600 National Guard troops.

Before reaching Florida, Nicole unleashed extensive flooding across much of the Bahamas, including the islands of Grand Bahama, Eleuthera, Andros and the Abacos.