Naples, Fla., Oct. 24 - Hurricane Wilma lashed the southwest coast of Florida with 125-mile an hour winds this morning, causing heavy flooding and power outages, and forecasters warned that the storm was not likely to lose much power as it cuts a path across the Florida peninsula.

Winds from the category three hurricane extended up to 90 miles from its eye wall, toppling power lines and trees and bringing fierce horizontal rain and high seas through a large swath of south Florida - from the Florida Keys to Miami and Ft. Lauderdale on the state's Atlantic Coast. In Miami, winds were tracked at speeds of up to 100 miles per hour this morning. Tropical force winds extended up to 230 miles from the center, according to the National Hurricane Center this morning.

Gov. Jeb Bush requested this morning that 14 Florida counties be granted a major disaster declaration. The hurricane is Florida's eighth in the past 15 months.Wilma, which made landfall at 6:30 a.m. Eastern Daylight Time at Cape Romano, was moving this morning at 20-miles per hour, the hurricane center said on its web site. Cape Romano is about 22 miles south of Naples.

In the Florida Keys, an estimated 80 percent of the 78,000 residents ignored a mandatory evacuation order and shuttered themselves inside their homes. Key West Police Chief Bill Mauldin told CNN this morning that flooding was the worst he had seen in recent years, but that it was too early to tell the extent of structural damage.

An area from Key West north to Naples was largely without power, water or emergency services. A storm surge of 12 to 18 feet is expected in areas of southwest Florida, with a surge of five to nine feet expected in the Florida Keys.

"We did everything possible to help people leave and if they made the decision to stay, it was theirs," said Mr. Mauldin.

Statewide, about 15,000 people are staying in more than 70 emergency shelters, according to the Red Cross.

Tornadoes were reported Sunday night on the Atlantic Coast north of Lake Okeechobee and near Melbourne and Cocoa Beach.

The storm was expected to rapidly move northeast across the state, reaching the Atlantic Ocean east of Lake Okeechobee, near where Hurricanes Frances and Jeanne made landfall last year.

As hundreds of thousands of people prepared for Hurricane Wilma, another tropical system dumped torrential rain on Haiti and the Dominican Republic on Sunday. The Associated Press reported that at least one person was killed in Haiti.

Tropical Storm Alpha was the 22nd named system in the Atlantic Ocean this season, breaking the record set in 1933 and forcing weather officials to turn to the Greek alphabet for a name. The storm, which was downgraded to a tropical depression later Sunday, also made this hurricane season the most active since officials began keeping records 150 years ago.

In its wake, Hurricane Wilma left the Yucatán Coast a wreck, devastating the international airport, eroding beaches and severely damaging dozens of huge resort hotels, robbing tens of thousands of Mexicans of their livelihoods.

With food scarce and few businesses open, looting broke out as soon as the storm passed.

"It's so sad," said Oscar Kury, a manufacturer of uniforms for hotel workers, as he surveyed the damaged discos, bars, restaurants and hotels along Cancún's famous tourist strip. "It's going to take a year to rebuild this."

Residents and tourists emerged from shelters and homes after 60 hours of howling wind and rain to find Cancún transformed from a Caribbean playground to a tangled maze of flooded streets, downed power lines, toppled signs and broken glass.

At daylight on Sunday, looters broke into stores, carrying off food, televisions and computers, among other things. The police made arrests, but they were stretched too thin to stop the stealing. Officers also discovered three bodies, apparently those of homeless people.

Some of the 20,000 tourists who weathered the storm in schools, cultural centers and small downtown hotels began to get desperate after a third day of eating little more than tuna fish and crackers. Most had left luggage at the resorts and were not allowed to retrieve their belongings.

In Playa del Carmen, just south of Cancún, several inmates fled a prison when a wall collapsed.

Flooding severed Isla Mujeres, a 4.2-mile-long island off Cancún, into three parts, and it remained cut off from the mainland. There were still no reports of how its 10,000 inhabitants fared, said Gov. Félix González Canto of Quintana Roo province.

As Wilma turned toward southwestern Florida, tens of thousands of residents fled. The storm lost strength as it crossed land, but regained Category 3 strength as it crossed the Gulf.

In Collier County, which includes Naples and is one of the nation's fastest-growing regions with about 300,000 residents, officials estimated that more than 80 percent of the population had evacuated and that more people were still leaving Sunday evening.

Ben Nelson, the state meteorologist, said the storm would likely maintain hurricane strength as it crossed Florida, possibly bringing winds of more than 100 m.p.h. to the heavily populated counties of Palm Beach, Broward and Miami-Dade. Because of the storm's sprawling size, strong winds could affect almost all areas south of Orlando, Mr. Nelson said.

Across the state, local officials said they were well prepared for the storm, having learned ample lessons from the seven other hurricanes to hit Florida in the last 14 months and from the recent troubles after Hurricane Katrina.

Governor Bush said gasoline remained abundant along evacuation routes and that much more, at least 220 million gallons, was waiting at the state's ports.

An additional 131 million gallons are scheduled to arrive on 29 ships over the next few days, said Mr. Bush, whose state experienced such serious gas shortages during last year's hurricanes that many drivers were stranded along highways. On an average day, Floridians consume about 23 million gallons of fuel.

About 2,400 Florida National Guard troops were activated for duties including traffic management and search-and-recovery efforts, Mr. Bush said. An additional 3,000 troops are on standby.

Mr. Bush said search-and-recovery teams, with hovercraft, boats and nearly three dozen Chinook and Blackhawk helicopters, were ready to enter the Keys if roads were impassable. Officials in Collier County put teams with airboats and swamp buggies at several staging areas.

More than 200 truckloads of ice, 200 truckloads of water and 86,000 meals were waiting in Jacksonville and at Homestead Air Force Base, south of Miami. And nearly 7,000 utility workers with more than 3,000 trucks were poised to restore power to homes and businesses, hundreds of thousands of which could be affected by the storm.

At a concrete bunker on the edge of Naples, Dan E. Summers, the director of emergency management for Collier County, took a nap on Sunday afternoon, expecting a long night with Hurricane Wilma. "We're very well prepared," he said.

At the crowded Tin City Docks in downtown, boat owners were stripping radar and communications gear from their craft, tightening their lines and hoping for the best, though they acknowledged a substantial storm surge was likely to devastate the marina.

Throughout the city, Parks Department workers in small dump trucks with flashing lights were scooping up tree limbs, lids for garbage cans and other debris from the streets. "You don't want any missiles flying around," Steve Madsen said as he paused his truck in the Old Town section of Naples.

People in Florida have been following the progress of Hurricane Wilma since last Wednesday, when its winds reached 175 m.p.h. and the National Hurricane Center in Miami declared it the most powerful Atlantic hurricane ever. Residents gassed up their cars and laid in supplies, and they waited. Many decided to head north to hotels and homes of relatives and friends. Others temporized to see whether the hurricane would actually head toward them.

"Wilma has been tormenting us all week," said John Turner, 49, a real estate broker, as he stood on the beach watching the gulf boil up on Sunday afternoon. Two people were swimming and a half-dozen young men were trying to surf in the still fairly flat seas.

In the Yucatán on Sunday, the scene was far from placid.

On the 17-mile-long barrier island that is home to Cancún's resort hotels, the damage was extensive. In most places, the beaches were stripped of their famous white sand, leaving nothing but limestone rocks.

Almost every hotel suffered broken windows, smashed signs and fallen glass walls. Some had structural damage, with rooms and balconies facing the ocean ripped away. Several lobbies were gutted by the swirling storm surge.

At the Park Royal Hotel, the banquet room was reduced to a sea of glass and twisted aluminum studs. The winds destroyed the seaside restaurant, and the waves reduced the beach to a rocky slope, studded with the remains of thatched beach umbrellas.

Carlos Rangel Castelazo, 63, drove his pickup truck through the floods to see what was left of his marina on the lagoon side of the island, where he rents out powerboats. "It's gone," he said. "Completely submerged."

"I think the intention of everyone is to try to rebuild something for the high season of December," he said. "But it's very little time."

On Sunday afternoon, the government seemed overwhelmed with the task of clearing roads and getting food to evacuees. Many neighborhoods in the northern part of Cancún were still flooded, and marines were busy ferrying food to temporary shelters. The Mexican army brought in bulldozers and backhoes to clear the main coastal highway from Cancún to Chetumal, the province capital.

Government officials were making no predictions about when electricity would be restored or the airport would be reopened.

President Vicente Fox surveyed the damage in Cancún by helicopter on Sunday afternoon, but several trucks of relief aid promised by the federal government had yet to arrive from Mérida, the closest city. The highway was jammed with cars fleeing the area, witnesses said.

When he arrived in Chetumal, Mr. Fox pledged $1.1 billion to begin reconstruction.

"Right now, we should worry about lives, worry about families' safety in shelters, worry that they are fine in a shelter, worry that the shelters are well-supplied, and after that we will go into material things," he said.

But mindful of the region's importance to Mexico's tourism industry, Mr. Fox added, "Our greatest worry is restoring tourism to its full operation quickly."

Joseph B. Treaster and Abby Goodnough reported from Naples, Fla., for this article; and James C. McKinley Jr. from Cancún, Mexico. Tim O'Hara contributed reporting from Key West, Fla.; Joe Follick from Tallahassee; and Joanna Hogan from Fort Myers.