In the barrage of hurricanes that hit Florida over the past year, Miami-Dade and Broward counties were among the few spots that were spared any significant damage. Hurricane Katrina took care of that.

Katrina killed six people, downed power lines and trees, and left behind a soggy mess in South Florida. Now the storm is taking aim at the Florida Panhandle, which suffered the worst damage in earlier storms. Katrina could hit the Gulf Coast on Monday.

Gov. Jeb Bush (R) urged residents of the Panhandle and northwestern Florida -- areas hit by Hurricane Ivan last year and Hurricane Dennis this year -- to monitor the storm and make the necessary preparations. Bush said he asked for federal disaster assistance for Miami-Dade and Broward counties.

Late Thursday and early Friday, Katrina flooded homes, blocked roads by toppling large trees, and left more than 1 million homes and businesses without electricity. It was the sixth hurricane to strike Florida in a little more than a year.

"I'm so sick of this," said Pat Jackson, an interior decorator in Homestead, which had some of the worst flooding. Her apartment building was flooded with several inches of water. "It seems like every other week or month another one comes," she said.

Scenes of Katrina's impact were everywhere -- work crews sawing trees crippled by the winds, people canoeing through inundated streets, a 727 cargo plane sitting along a runway fence, sailboats resting askew on a sandy shore.

Katrina was a Category 1 storm with 80 mph winds when it hit Florida on Thursday.

"We had wind coming from two directions. It sounded like a super wind tunnel," said Scott Resnick, 42, who rode out the storm in Hallandale Beach.

By Friday afternoon, Katrina was churning in the Gulf of Mexico on a path to make a second landfall anywhere from the Florida Panhandle to Louisiana as early as Monday, possibly as a Category 4 storm.

The death toll from Katrina was set at six, including three people killed by falling trees and two boaters who tried to ride out the storm in their crafts. Authorities had said the toll was seven, but they revised it after determining that one death was not storm-related.

President Bush was being given regular updates on the storm and the Federal Emergency Management Agency was ready to help, White House spokesman Trent Duffy said. Federal resources already in place include food, water and ice, Duffy said.

As it moved into the Gulf on Friday, Katrina became a Category 2 hurricane with 100-mph winds and lashed the Florida Keys with strong outer bands that could dump 15 to 20 inches of rain over the island chain.

The National Hurricane Center said Katrina was expected to strengthen significantly over warm Gulf waters and warned residents from Florida to southeastern Louisiana to be ready.

"It's going to be a similar track to Dennis, potentially," meteorologist Chris Sisko said. Dennis hit near Pensacola Beach on July 9 as a Category 3 hurricane, with sustained winds of 120 mph.

Katrina's first swipe across Florida left about 50 homes flooded in Homestead and 40 mobile homes damaged in Broward County. On Key Biscayne, dozens of families were forced to evacuate their homes after they were flooded by three feet of water.

Street flooding and debris strewn on the roads made many streets impassable, a situation made worse by power outages that affected street lights.

An overpass under construction in Miami-Dade County collapsed onto a highway. No injuries were reported, but the freeway -- a main east-west thoroughfare -- was closed for 20 blocks.

David Carter rode out the storm in his Coconut Grove home, listening as avocados were torn off branches and tossed at his house.

"It sounded like tiny bowling balls hitting the top of the roof and rolling down," he said. "You just heard the big thud."

A family of five missing after they went sailing as Katrina approached the Florida coast was found uninjured Friday on a mangrove island. Edward and Bettina Larsen and their three children had been stranded near their beached boat and had to be hoisted to a helicopter.

Wilfredo Lopez, left, and Orlando Maderos paddle down a street in Homestead, Fla. About 50 homes in the community, south of Miami, were flooded. A man uses his camera phone to record storm damage in Hallandale, Fla., north of Miami. Six people died as a result of the hurricane.