Katrina may be strongest hurricane ever seen in Gulf

People drive through a flooded neighbourhood on four wheel vehicles in South Miami, Florida today, after hurricane Katrina struck. Picture / Reuters

Hurricane Katrina gathered force in the warm turbulence of the Gulf of Mexico yesterday after wreaking devastation across southern Florida, and was expected to rebound on the battered state possibly as soon as tomorrow.

The hurricane was upgraded to a category three "major hurricane" yesterday, meaning it carried winds of more than 120mph. There are fears it could bounce back tomorrow as a category four - a hurricane of potentially catastrophic intensity with winds of 130mph, capable of causing widespread damage, US authorities warned.

Alarmed residents who have had barely time to clear up damage inflicted by Hurricane Dennis last month, or Hurricane Ivan last September, were braced this weekend for further destructive tornados, deluges and fierce winds.

At least seven people were killed when Katrina ripped across Florida's southern tip on Friday, four of them struck by flying trees. Fifty homes were flooded, and thousands of trees uprooted.

Ending a week of extreme weather worldwide, the storm was expected to swing northwards on a course heading somewhere between the southern Florida panhandle and the Louisiana coast. In the line of attack are the city of New Orleans, and oil and gas installations. Some oil drilling platforms in the Gulf of Mexico have already been evacuated.

Florida has been pummelled by six powerful hurricanes since last August, in what forecasters describe as an "unusually active season". Environmental campaigners say the turbulence is a product of global warming disrupting world weather patterns. Katrina is the 11th storm of the Atlantic hurricane season, which began on 1 June.

That is seven more than are usually whipped up by this stage of the season in the Atlantic, Caribbean and Gulf of Mexico, the US's National Hurricane Centre said. The season ends on 30 November.

Katrina's advance is being watched closely in Europe, where many people have felt subjected to comparable celestial punishment this week. From deluged south-eastern Europe, where 43 died in tumultuous rainstorms, to tinder-dry Portugal, where 11 new fires flared yesterday despite weeks of desperate firefighting, Europeans have been assaulted by weather extremes unknown for generations.

Hardest hit was Romania, where 31 died, many of whom drowned when water engulfed their homes. Austria, Germany, Bulgaria and Switzerland reported 12 dead, with vast areas under water. Fears remain that floodwaters could cause the Danube to burst its banks and present further hazard.

In the small Swiss town of Thun, the local football stadium was destroyed, a loss given international prominence by the club's qualification last week for the Champions League, in which it will take on Arsenal.

Experts seeking an explanation point to the irregularity of the jet stream, the wriggling ribbon of fast-moving wind that drives Europe's weather from the Atlantic. A convulsive kink last week whipped turbulence into Eastern Europe, and locked Iberia in its pocket of hot tranquillity.

"But the jet stream is a permanent feature, it always wanders around, that's nothing new," said Wayne Elliott, a weather forecaster from the Meteorological Office in Exeter.

"The jet stream moves north in summer, south in winter, and the important thing is that it didn't come as far south as was expected last autumn. That's why the rains failed in Iberia, and why northern Europe is unsettled.

"Such behaviour is consistent with predictions by scientists who argue the climate is changing. Global warming could be the key."

The World Wildlife Fund goes further. "Global warming has started to exacerbate the frequency and intensity of meteorological catastrophes," a WWF spokesman said on Friday.

"Politicians must curb [carbon dioxide] emissions now."

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