MIAMI, Oct 20 (AFP): Hurricane Wilma Wednesday became the most powerful storm ever recorded in the Atlantic as it hurtled toward Mexico and the US coast, packing terrifying 280-kilometer-an-hour (175-mile-an-hour) winds.
Authorities ordered the evacuation of tourist resorts in the path of the monster storm, which the US National Hurricane Center said was "potentially catastrophic".
Alerts were ordered across the Caribbean, but Mexico's Yucatan Peninsula seemed most at risk of becoming Wilma's first target.
Authorities ordered evacuations of high-risk areas along the coast, particularly the island of Mujeres close to the holiday resort of Cancun. Organisers cancelled the MTV Video Music Awards Latin America ceremony, planned for Wednesday night in Cancun, because of the storm.
The peninsula could be hit by Wilma early Friday.
Tourists and non-residents were also told to leave the low-lying Florida Keys island chain off the southern tip of Florida.
The southern US state was bracing for Wilma to arrive late Saturday, and a state of emergency was declared in the Keys. President George W. Bush has been briefed on the storm, a spokesman said, and he called on Americans to heed warnings about Wilma.
At 1500 GMT, Wilma was about 520 kilometers (325 miles) southeast of the Mexican resort of Cozumel on the Yucatan.
The hurricane's barometric pressure, 882 millibars, was "the lowest pressure on record for a hurricane in the Atlantic basin," the center said. The lower the pressure, the stronger the storm is.
At 1200 GMT, winds at the center of the storm were clocked at 280 kilometers (175 miles) per hour. The hurricane center said fluctuations in intensity were likely as the record-matching 21st storm of the Atlantic season moved toward land.
"Wilma is a potentially catastrophic" hurricane, the Miami-based monitoring center said.
Authorities in Cuba, Jamaica, Mexico, Nicaragua and the Cayman Islands have all issued hurricane alerts. Eleven people have been killed in flooding after two weeks of torrential rainfall in much of Haiti over the past two weeks, but authorities made no immediate link to Wilma.
Cuba has ordered 5,000 people evacuated from flood-prone areas along the storm's path.
Honduras also ordered preparations for evacuations as heavy rain began to fall. Widespread flooding was reported in Jamaica from rainfall sparked by the hurricane, and nearly 25 inches (64 centimeters) of rain was expected to drench mountainous areas of Cuba through Friday.
World oil prices have eased, however, amid hopes that Wilma would not hit oil installations on the storm-weary US Gulf Coast.
It is the 12th full-blown hurricane of the Atlantic season, and a series of the storms have left thousands dead in Central America and along the US Gulf Coast.
Hurricane Katrina killed more than 1,200 people on the US Gulf Coast after it struck on August 29, and Hurricane Stan left more than 2,000 dead in Guatemala alone earlier this month. Dozens more were killed by the storm in El Salvador, Nicaragua and Mexico.
Florida has already been battered by hurricanes Dennis and Katrina this year, and the state's governor, Jeb Bush, brother of US President George W. Bush, was downcast at the prospect of a fresh hit.
"Why us?" he said. "How does a storm take a sharp 90-degree turn?"
A climate study released Monday said the continental United States will face more extreme temperatures during the next century and more intense rainfall along the Gulf Coast.
The study, published by the journal Proceedings of the National Academy of Sciences, warned that greenhouse gases will likely be twice current levels by the end of the century.
It predicted that the southwestern United States could endure as much as a 500 percent increase in hot events, leaving less water for the growing population, and that the Gulf Coast region would receive more rainfall over shorter periods of time.