The storm moved with fierce speed, making landfall on Florida's west coast about 6:30 a.m. at Cape Romano, a deserted area south of Marco Island. Within six hours, Wilma had traversed the state, exiting near Palm Beach on the Atlantic coast.

The Panhandle was the only part of Florida spared the effects of the record-tying 21st storm of the 2005 hurricane season.

With sustained winds of 125 mph, Wilma was a Category 3 hurricane at landfall; the storm dropped to a Category 2 as it crossed the state, then intensified into a Category 3 as it headed northward into the Atlantic.

By midafternoon, rain had stopped falling along Florida's east coast.

Officials at the National Hurricane Center in Miami said Wilma's furious pace as it crossed Florida was not surprising, given that the storm earlier had ballooned from a tropical depression to the strongest hurricane on record in under four days.

President Bush on Monday authorized a major disaster declaration for the state, making federal aid immediately available in most of Florida. Wilma was the eighth hurricane to hit the state in 13 months.

''We're tired of hurricanes, I can tell you that,'' said David Paulison, acting director of the Federal Emergency Management Agency.

Preliminary estimates put damage from Wilma between $4 billion and $10 billion. More than 2 million Florida homes were without power on Monday, Paulison said. About 36,000 people had sought refuge in 124 shelters across the state.

But the major concern was for those who had ignored days of warnings about Wilma and decided to ride out the storm. Paulison said disaster teams were especially worried about those who had stayed in their mobile homes.

Emergency officials said that in the Florida Keys, about 90 percent of residents had refused to evacuate.

Seawater pushed by Wilma's winds had swamped much of the Keys, local officials said Monday. The flooding appeared to be the worst in years.

''Currently in the Lower Keys, we're experiencing severe flooding. We're still having storm surge as we speak,'' Greg Artman, a Monroe County emergency operations spokesman, said early Monday.

Power was out Monday to the entire island chain, Artman said. U.S. Highway 1 - the only link with mainland Florida - was impassable in two places. A water main that supplies Key West had broken because of the storm, and Artman said Key West International Airport was under water and had been severely damaged.

''We have reports from all over about people's houses being flooded,'' Artman said. ''We have everything from people talking about three feet of water in their house to a couple of inches.''

Colleen Englert, a spokeswoman for the state emergency operations center in Tallahassee, said one man was killed in Collier County when his roof collapsed. Another Collier County man with a history of diabetes and heart disease collapsed and died - possibly from hurricane-induced stress - when he went outside to inspect the damage, Englert said.

And in St. Johns County in northeastern Florida, far from Wilma's path, a woman who was fleeing from the storm died when the vehicle she was in had a blowout and overturned, Englert said.

In Naples, just north of where Wilma crossed into the state, intense winds snapped palm trees in two. Collier County Commission chairman Fred Coyle said that although Naples escaped a damaging storm surge, many streets were under two to three feet of water.

The resort community of Marco Island, which was under a mandatory evacuation order, suffered limited structural damage. City manager William Moss said about 90 percent of the island's residents had left ahead of the storm.

In Clewiston, about 60 miles inland, streets were flooded and 200-year-old trees lay on their sides. Shop windows were blown out, and some mobile homes were flipped off their concrete foundations.

The storm's winds, which strengthened as Wilma passed over Florida's east coast, broke a construction crane in half in Hollywood, near Miami.

Wilma also blew out the windows in several Miami skyscrapers. Lt. Bill Schwartz, a spokesman for the Miami-Dade Police Department, said the headquarters building shook violently as the hurricane passed over.

Schwartz said only one looting incident had been reported in Miami, when several men broke into a convenience store in search of beer. He said the city had no plans for a curfew.

Emergency officials also said it was a blessing that Wilma had hit hardest in an uninhabited area: Everglades National Park. Chris Landsea, a forecaster with the National Hurricane Center, said the storm temporarily raised the ocean level in that area by 12 to 18 feet.

Danny Daniels, an airboat captain who is the fifth generation of his family to live on the southwestern edge of the Everglades, took the storm warnings seriously and rode the hurricane out in a secure house inland. Still, Daniels said the experience was frightening.

''You could here the gusts coming before you felt them, and the trees popping like a series of firecrackers as they snapped. It was a scary feeling, like you'd get from skydiving. Except it lasted for hours,'' said Daniels, 50.

FEMA's Paulison said Monday that federal response teams were prepared to take quick action to assist residents affected by Wilma; the agency was highly criticized in the wake of Hurricane Katrina.

''We're all stressed out a little bit, but we're prepared to handle this,'' Paulison said.

In contrast to Katrina relief efforts, Paulison said: ''We are in a very robust communications with the state, we are working in partnership with them. We can move our stuff in as quickly as the state asks.''

Meteorologists said Wilma would continue to cause heavy winds and rain as it marched north along the Atlantic coast to New England, where the storm could strike again Thursday.

Wilma at a glance

Death toll in Florida: 6

Overall death toll: 25

People affected by power outages: 6 million

Financial loss: $2 billion-plus

Top winds: 125 mph

This is the eighth hurricane to hit Florida in the past 15 months.