Early Monday, Jacksonville, Fla. broke its all-time record, with storm surges bigger than Hurricane Dora in 1964 and is under a Flash Flood Warning until 12:45 pm ET. Floodwaters continue to rise in the cities after heavy rainfall.
More than 180,000 people huddled in shelters in the Sunshine State and officials warned it could take weeks for electricity to be restored to everyone.
While the projected track showed Irma raking the state's Gulf Coast, forecasters warned that the entire Florida peninsula - including the Miami metropolitan area of 6 million people - was in extreme peril from the monstrous storm, nearly 400 miles wide.
Irma, a Category 5 hurricane with 180 miles per hour winds, hit Puerto Rico on Wednesday night after smashing a string of small northern Caribbean islands, leaving many residents without power.
That's because some islands are extremely hard to access.
The main highway into the Florida Keys, Southbound US-1, remained closed Monday afternoon - troopers could only make it as far as Mile Marker 88.
Large debris is blocking access, and a 150-foot stretch "has some buckling", Newman said. "No cell service in at least the lower and middle Keys", said Bill South of the National Oceanic and Atmospheric Administration.
"Pray, pray for everybody in Florida", Gov. Rick Scott said on "Fox News Sunday".
Rough surf churned up buy the approaching hurricane damage the docks at Whale harbour in the Florida Keys as winds and rain from the outer bands of Hurricane Irma arrive in Islamorada, Florida, Sep.
The storm was passing north of the Leeward Islands at 2 p.m. ET Saturday, the hurricane center said, and was moving northwest at 13 miles per hour. Then, there's the lone model taking the storm through The Bahamas before making another Florida landfall. But Shiveley said the water never crested over the city's barriers. But that doesn't mean all Floridians should try to go back home. But we are asking residents to stay where they are.
"The outer wall that we caught, the whole outer sweep, we were very, very lucky. that eastern sweep didn't give us the real bang and eastern punch that would've drowned us", he said.
More than 6 million homes and businesses were still without power in Florida and nearby states.
What else should I know about the hurricane? That's 62 percent of the state's power customers, and there are several counties where 80-90 percent of customers are without power.
A Tropical Storm Warning is in effect for.
At its St Lucie nuclear plant located about 120 miles (190 km) north of Miami, FPL started to reduce power at Unit 1 due to salt buildup from Irma in the switchyard, NRC spokesman Roger Hannah said.
Florida has long dealt with hurricanes, including a stretch of eight hurricanes in two years while Jeb Bush was governor, but Irma's wide reach has proved daunting. The death toll from the storm also rose in the Caribbean, where at least 34 people are confirmed dead. Hurricane Harvey made landfall in Texas in August.