Hurricane Georges has already brought devastation to the Caribbean, where 110 lives have been lost in the past week, most in St Kitts, Antigua and Cuba. Now it threatens southern Florida, starting with the Lower Keys, the chain of islands that is the closest United States land to Cuba.
In Miami, the turquoise mass of water that always seems higher than the land is flecked with white edgings in places, even though, as yet, there are no waves. The palm branches are waving like the arms of a tightrope walker. Those white clouds on the horizon are somehow aberrant; the shapes are wrong, and they are swelling as more banks build.
In South Beach, where every pastel deco building has its history, a few ocean-front cafes are crowded at mid-morning - crowded because the rest are closed. The banging of hammers is all round as workmen nail wooden boards across the plate-glass hotel fronts. A few carefree couples cross the road, beach mats under arm, frolicking in amazed delight that they have the whole expanse of white sand to themselves. But Route 41 is as busy with cars as in the rush hour. Urgently, but without panic, Miami Beach is preparing to abandon itself to the elements.
On local and national television, the recurrent map shows the pendulous shape of Florida, with the long strip of Cuba below like an underlining. In the intervals between the forecasts, the white catherine wheel with the red centre edges across the northern shore of Cuba. Occasionally its projected path is plotted by computer. It could move north across the Florida Keys and up towards the Florida Panhandle; it could move north- east, closer to Miami and the destructive trajectory of its predecessor Hurricane Andrew six years ago. Or it could sweep to the north and east, in a quarter- circle, and back out to sea.
But at the National Hurricane Centre, judiciously sited, since Hurricane Andrew, further inland beyond the western fringe of Miami, the experts fear, and plan for the worst. The worst would be the first, slamming into the Lower and Middle Keys, then heading to the densely populated Panhandle, which is just recovering from a series of tropical storms. That would extend the relief effort on three fronts.
Moving over the warm water of the Gulf would also give the hurricane a chance to pick up speed. With winds of 120mph already forecast, that is the greatest fear.
Teams are already in the US possession of Puerto Rico, which was one of the first places to be struck by Georges. They are readied for southern Florida, but to extend themselves as well to north-western Florida is asking much. Re- inforcements are already being drafted in, with instructions to ensure they get here before the force of the wind halts even military flights.
By midday, the Keys were warned they were the next target; the causeway, the single link with the mainland, would be closed at 4pm and a curfew would be in force from 9pm.
In the previous 24 hours almost 100,000 people were evacuated, most by car along the dual carriageway that links Key West at the south-western tip with Miami.
Only a few stalwarts, and reporters, remain. A vast emergency shelter has been set up to receive them on the university campus that houses the hurricane centre. The Keys are too low-lying to have their own safe shelters.
The experts continue their warnings. "To everyone of you folks living on the Keys, I urge you to get out now; you still have two hours," says Jerry Jerrold, head of the hurricane centre. "After that, if you've made a bad decision, you're on your own." The spokesman for the centre has apocalyptic details in his arsenal of warnings. "Hurricanes bring out the varmint. You'll get alligators, scorpions and snakes coming out, seeking higher ground."
The evacuation is still voluntary, but most of those who would leave have gone. Many of those remaining are the poor who have no choice.
British holiday operators said yesterday that they had evacuated British tourists from south Florida. Flights to Orlando were continuing normally.