Meteorologists predicted Irma's center would blow ashore Sunday morning in the perilously low-lying Florida Keys, then hug the state's west coast, plowing into the Tampa Bay area by Monday morning.
Hurricane Irma roared through the Florida Keys on Sunday with punishing 130mph winds and began pushing its way north, knocking out power to more than 1.5 million people across the state and collapsing a construction crane over the Miami skyline.
Read: Mother Nature's wrath: Is climate change making mega-hurricanes the new normal? . Southbound US Route 1 - the only road connecting the Keys - is closed, Florida Keys spokesman Andy Newman said.
On Florida's west coast, resident Charley Ball said he expected a storm surge to completely engulf the island of Sanibel where he lives.
"We are way better than we used to be but we are nowhere near where we could be", he told AFP.
In the Jacksonville area, close to the Georgia line, storm surge brought some of the worst flooding ever seen there, with at least 46 people pulled from swamped homes.
Hurricane Irma hit Florida with brutal force.
Rick Scott is cautioning citizens that the worst of the storm itself may be over, but the storm surge and flash floods still pose a deadly threat. At least 34 people were left dead in the storm's wake across the Caribbean.
Authorities continued to warn of electrocution from downed power lines, sewage leeks, flooding and even snakes and alligators.
As the eye neared the island and Irma forced the area's barometric pressure to drop dramatically, the roommates said they could feel a popping sensation in their ears similar to when a plane descends during landing.
The hurricane's powerful eyewall crossed the Gulf of Mexico island at 3:35 p.m. Sunday as a Category 3 hurricane, after raking Cuba and slamming the Florida Keys.
Hurricane Irma: Eye of storm hits Florida west coast
The US and British Virgin Islands were also pummeled by Irma.
A Navy aircraft carrier was due to anchor off Key West to help in search-and-rescue efforts. Prime Minister Gaston Browne described the result as "total devastation". The company took offline one of two reactors at a nuclear plant south of Miami.
As dawn approached, mayors and emergency responders across the state implored citizens to stay in place and not to venture outside until crews can assess damage and give the all-clear that it's safe to leave their homes.
France said 10 people died on its side, while the Netherlands said the storm killed four on the Dutch side, called Sint Maarten, where 70 percent of the infrastructure has been destroyed.
Irma was the first Category 5 hurricane to hit Camaguey in 85 years, according to the province's state media radio station. It left thousands of homes, businesses and hotels flooded.
A auto sits abandoned in storm surge along North Fort Lauderdale Beach Boulevard in Fort Lauderdale.
Gwinnett County is gearing up as Hurricane Irma moves toward Georgia.
A Miami roof got ripped off because of the winds.
Despite weakening, Irma's winds remain a major risk, particularly because of flooding, forecasters have warned.
"Tonight, I'm sweating", she said.
Irma had triggered orders for more than six million people in the United States to flee to safety, one of the biggest evacuations in the country's history.