Rescues were underway on Thursday after Hurricane Milton tore a path of destruction across Florida as a Category 3 storm before moving off the east coast into the Atlantic.
The storm left millions without power, spawned numerous tornadoes and dumped as much as 16 inches of rain on St. Petersburg.
At least four deaths were blamed on the storm, the second to hit Florida's Gulf coast in two weeks, as first responders and emergency crews began assessing the full scope of the damage in the morning light.
The deaths came from tornadoes that hit a retirement community in St. Lucie County the Sheriff's Office said in a statement on Thursday morning.
Milton made landfall Wednesday evening at Siesta Key, about 70 miles south of Tampa, with maximum sustained winds of about 120 mph, the National Hurricane Center said.
Flash flooding warnings were posted for central and northern Florida, along with storm surge advisories in effect from Florida to southern Georgia, the agency said.
Residents of Hillsborough, Pinellas, Sarasota and Lee counties on the west coast were advised to remain under shelter because of downed power lines, damaged bridges and debris in the roadways, the Associated Press reported.
"We'll let you know when it's safe to come out," Sheriff Chad Chronister of Hillsborough County, home to Tampa, said on Facebook.
In St. Petersburg, Milton's powerful winds ripped open the roof of Tropicana Field, home of the Tampa Bay Rays baseball team, leaving tattered pieces of fabric flapping from beams on the structure.
A construction crane collapsed in downtown St. Petersburg, crashing into an office building and blocking the street.
Milton dumped about 16 inches of rain in parts of Pinellas and Hillsborough counties in roughly six hours and caused flooding along the coast and on the barrier islands on the Gulf Coast, the Tampa Bay Times reported.
Even before Milton made landfall, it spawned dozens of tornadoes that destroyed about 150 homes and killed residents of St. Lucie County, the publication said.
More than 3.2 million homes and businesses were without power Thursday morning.
Milton struck about the same area of Florida where Hurricane Helene came ashore two weeks ago as a Category 4 storm, lashing the state with strong winds and heavy rains before moving north into Georgia and the Carolinas, and killing at least 230 people.