HURRICANE Irma has killed at least seven people, reduced islands to rubble and left hundreds of thousands without power as it tears through the Caribbean.
A two-year-old child was killed on the two-island nation of Antigua and Barbuda as a family tried to escape a damaged home, said prime minister Gaston Browne.
"Barbuda is practically uninhabitable," he said. "It's just total devastation, Barbuda now is literally rubble. It is absolutely heart-wrenching."
The ferocious Category 5 hurricane damaged 95 per cent of the structures on the small island, with more than 800 people left homeless. Mr Browne said the damage was "horrendous", with homes demolished and roads and telecommunications systems destroyed. He said the recovery effort would take months, if not years, and cost at least $100 million.
Irma also flattened 95 per cent of the idyllic French/Dutch resort island St Martin, with major damage to the airport, cars overturned and severe flooding in coastal villages.
St Martin is without drinking water or electricity and in dire need of emergency assistance, said local official Daniel Gibbs. "It's an enormous catastrophe," he told Radio Caribbean International. "I have a population to evacuate."
French President Emmanuel Macron earlier warned "the toll will be harsh and cruel."
There are now three hurricanes in the Atlantic, something that hasn't happened for seven years.
As Irma tracked a path through the Caribbean with wind gusts of up to 360km/h, Hurricane Jose was 1675 kilometres east of the Lesser Antilles in the Atlantic and packing sustained winds of 120km/h, and Katia in the south-western Gulf of Mexico was blowing sustained winds of 121km/h. A hurricane watch was in effect for the coast of the Mexican state of Veracruz, where torrential rain is expected, according to the National Hurricane Centre.
Further west, Irma is tearing up Caribbean islands with historic 297km/h winds and gusts of 360km/h on its way to a potentially devastating hit on Florida.
Governor Rick Scott said he planned to activate 7000 National Guard soldiers by Friday and warned that Irma is "bigger, faster and stronger" than Hurricane Andrew, which pummelled south the state 25 years ago and wiped out entire neighbourhoods with ferocious winds.
Arizona meteorologist John Patrick said Irma had now had winds of almost 300km/h for 34 hours, longer than any other hurricane across the globe, with Typhoon Haiyan holding the record at 24 hrs in 2013. Haiyan killed 6300 people in the Phillippines alone.
"This could easily be the most costly storm in US history, which is saying a lot considering what just happened two weeks ago," said Brian McNoldy, a hurricane researcher at the University of Miami.
"It's a humdinger," said Colorado State University meteorology professor Phil Klotzbach, who warned the Leeward Islands would be destroyed. "This thing is a buzz saw."
By Wednesday evening local time, the centre of the storm was 80km north of San Juan, Puerto Rico's capital, and heading west-northwest at 26km/h. More than half the island - around 900,000 people - was without power and nearly 50,000 people without water. Fourteen hospitals were using generators after losing power, and trees and telegraph poles were strewn across roads.
Blanca Santiago, who works in a beachside hotel in San Juan, said the howl of the wind whipping the coastline sounded "as if there were ghosts inside my home."
On St Thomas in the US Virgin Islands, Laura Strickling spent 12 hours sheltering in a dark, boarded-up basement apartment with her husband and one-year-old daughter. "One of the things we loved about St Thomas is that it was so green. And it's gone," said Ms Strickling, who moved to the island with her husband three years ago from Washington, DC. "It will take years for this community to get back on its feet."
The strongest Atlantic Ocean hurricane ever measured destroyed homes and flooded streets across a chain of small islands in the northern Caribbean, passing west directly over Barbuda and leaving the island of 1700 people virtually incommunicado.