Hurricane Irma's eyewall slammed into the Florida Keys Sunday, lashing the island chain with fearsome wind gusts as it bears down on the state's west coast where a mass exodus has turned cities into ghost towns.
Irma, packing maximum sustained winds of 130 miles (215 kilometers) per hour, was upgraded overnight to a Category Four storm as it closed in on the Keys, the National Hurricane Center said. Six million people — one third of the state's population — have been ordered to evacuate their homes ahead of the monster storm.
The eye of the hurricane was 20 miles east-southeast of Key West as of 8 a.m. local time), threatening dangerous storm surges up to 15 feet — enough to cover a house.
"THE WORST WINDS ARE YET TO COME."
For those still at home, it was too late to flee the wrath of one of the most powerful hurricanes ever to slam storm-prone Florida, after cutting a path of devastation across the Caribbean.
In Key West, police opened a "shelter of last resort" for those who had ignored evacuation orders.
The cities of Naples, Fort Myers and the densely populated peninsulas of Tampa Bay on Florida's west coast were in the crosshairs of the historic storm, which was churning slowly northwest at eight miles per hour.
"It's going to be horrible," Florida Governor Rick Scott said of Irma on NBC television Sunday morning. "Now we have to hunker down and watch out for each other."
More than 430,000 homes and businesses were already without power, mainly in southern Florida, according to utility company Florida Power and Light, which said it had "safely shut down" one of two nuclear reactors at its Turkey Point power plant.
At least 25 people have been killed since Irma began its march through the Caribbean, smashing through a string of islands from tiny Barbuda on Wednesday, to the tropical paradises of St. Barts and St. Martin, the US Virgin Islands, Puerto Rico, the Dominican Republic, Haiti and Turks and Caicos.
Terrified Cubans who rode out Irma in coastal towns — after it made landfall Friday as a maximum-strength Category 5 storm on the Camaguey archipelago — reported "deafening" winds, uprooted trees and power lines, and blown rooftops.
There were no immediate reports of casualties but it caused "significant damage," and enormous waves lashed the Malecon, Havana's emblematic seafront, causing seawaters to penetrate deep into the capital, AFP journalists reported.
Irma was smacking the keys 57 years to the day after Hurricane Donna hit the same area in 1960, destroying nearly 75 percent of the island chain's buildings.
The NWS urged Floridians to keep their shoes on, to take shelter in interior rooms — far from windows — and use helmets, mattresses, pillows or blankets for protection.
At North Collier Regional Park, a shelter outside Naples, anxious evacuees prayed their loved ones would remain safe.
Viviana Sierra, who sought refuge together with her dog, parents and brother, was sanguine about the prospect of finding her home and belongings destroyed.
"You can replace material things but your life is very important so I think it's better that we stay here," she said.
Storm surge, tornado risk
Irma was expected to move along or near Florida's southwest Gulf coast later Sunday and into Monday.
But the hurricane is so wide that authorities were bracing for destructive storm surges on both coasts of Florida and the Keys.
And hurricane-force winds are expected to lash the state as Irma rolls north toward Georgia.
The NHC also warned of tornado risks through Sunday night, with the greatest threat lying in areas east of the storm's path.
Strip malls, fast food restaurants and retail giants were closed for business on both of Florida's coasts.
MacDill Air Force Base in Tampa, the military installation home to US Central Command, issued mandatory evacuation orders ahead of the storm's passage early Monday, while the Kennedy Space Center on the east coast was also closed.
Reprieve from Jose
Warning that Irma would be more powerful than Hurricane Andrew — which killed 65 people in 1992 — Florida's governor had said all 20.6 million of the state's inhabitants should prepare to flee.
But some were determined to ride out the storm.
Scott Abraham, who lives on the fifth floor of a beachfront apartment building in Miami Beach, planned to ignore evacuation orders and stay put with his wife and two kids.
"If I lived in a house I would have left, but if it gets flooded here it's going to take a week at least to come back. I don't want that," he said.
In a welcome reprieve for the Caribbean, a second monster storm, Hurricane Jose — which had been heading toward the same string of islands pummeled by Irma — began to gradually weaken and shift course towards the north.
The deteriorating weather had grounded aircraft and prevented boats from getting relief to hard-hit islands. The US military was mobilizing thousands of troops and deploying several large ships to aid with evacuations and humanitarian relief.