Hurricane Irma has pounded the Caribbean, shredding homes and weather records and leaving at least 10 people dead before honing in on the United States where up to a million people were ordered to flee.
The evacuation of coastal areas of Florida and neighboring Georgia was the biggest seen in the US in a dozen years, as Brock Long, head of the US Federal Emergency Management Agency, warned: "It will be truly devastating.
"The entire southeastern United States better wake up and pay attention."
Barreling across the Caribbean, the rare Category Five Irma yesterday wielded monster winds and torrential rain, wreaking destruction on tiny islands like St Martin, where 60 percent of homes were wrecked, before slamming into the US Virgin Islands.
In its westward rampage, Irma packed winds of up to 185 miles per hour (295 kilometers per hour), an intensity that it sustained for 33 hours -- the longest of any storm since satellite monitoring began in the 1970s.
The latest bulletin from the Miami-based National Hurricane Center put the winds at 175 mph as the storm headed for the Bahamas.
Devastation was left in the storm's wake. The International Red Cross said 1.2 million people had already been hit by Irma, a number that could rise to 26 million.
On many islands, roofs were ripped off buildings as if by a giant's hand, shipping containers were tossed aside like matchsticks and debris flung far and wide, and airports, sea ports and mobile phone networks were knocked out.
At least four people were killed in the US Virgin Islands, officials told AFP, with the toll expected to rise.
"We lost a significant and a good number of assets... In terms of fire stations, police stations," Governor Kenneth Mapp said in a Facebook post, adding that the region's main health facility, the Schneider Regional Medical Center, lost its roof.
St Martin, a pristine island resort divided between France and the Netherlands, also suffered the full fury of the storm.
France said four had died and 50 were injured, two of them seriously. Sixty percent of homes were so damaged that they were uninhabitable.
The Netherlands said the storm killed at least one person and injured several others on the Dutch part of St Martin, where communications were all but cut off.
The Netherlands said it was racing to provide food and water for 40,000 people over the next five days, while France said more than 100,000 packages of combat rations were en route. A 200-member French team flew in to Guadeloupe to coordinate rescue efforts, headed by Overseas Territories Minister Annick Girardin.
Britain said it was sending two warships to help victims in the Caribbean, and earmarking $41 million in aid. The first vessel was expected to reach affected territories on Thursday.
Irma also laid waste to tiny Barbuda which suffered "absolute devastation," with up to 30 percent of properties demolished, Prime Minister Gaston Browne said.
"Barbuda now is literally rubble," Browne added.
One person is known to have died on the island of 1,600 residents, apparently a child whose family was trying to get to safer ground.
More than half of Puerto Rico's population of three million was without power, with rivers breaking their banks in the center and north of the island where Governor Ricardo Rossello activated the National Guard and opened storm shelters sufficient for up to 62,000 people.
As of yesterday evening the eye of the monster storm was located a few dozen miles north of Haiti, churning past Turks and Caicos and heading for the Bahamas.
Poor Haitians were left to face Irma's fury alone as authorities showed little sign of preparing for what forecasters said could be a catastrophic event.
Two people were injured when an uprooted coconut tree crashed onto their home near Cap-Haitien, authorities said, while neighboring Dominican Republic had evacuated about 5,500 people.
Cuba moved 10,000 foreign tourists from beach resorts in the exposed part of the island, and hiked its disaster alert level to maximum.
US President Donald Trump has already declared a state of emergency for Puerto Rico, the US Virgin Islands and Florida, while the southern state of Georgia ordered the mandatory evacuation of the city of Savannah and other coastal areas.
Florida is expecting to face the brunt of the storm from Friday night, with forecasters warning of sea-level surges of up to 25 feet (almost eight meters) above normal tide levels.
Tourists in the popular Key West islands were packing their bags on a mandatory evacuation order, with a similar order for residents due to follow.
"We can't save you once the storm starts," Governor Rick Scott told a press conference.
James Nickolos, a 69-year-old theology professor in Miami, said: "This morning I went to the beach as I do every morning, and it was very empty and beautiful but I had the feeling of watching a great beauty walking on a gang-plank to their death."
Trump said he was "very concerned" about Irma, but added: "Florida is as well prepared as you can be for something like this, now it's just a question of what happens."
Irma hit the Caribbean even as two other storms, Jose in the Atlantic Ocean and Katia in the Gulf of Mexico, were upgraded to hurricane status.
Katia, a Category One storm, is expected to hit the coast of the Mexican state of Veracruz before Friday.
Jose, following in the path of Irma and located east of the Lesser Antilles late Thursday, strengthened to a Category Three event, packing winds of up to 120 miles per hour, the US National Hurricane Center said.