"Just about everybody's been impacted by the storm in one way or the other," said Governor Jeb Bush. "We're kind of getting used to this."

At least two people were reported killed - a man electrocuted by a fallen power line in Miami and a truck driver crushed when ferocious winds flipped his cab - but there was no official confirmation yet of the fatalities.

Jeanne slammed ashore in the central Atlantic coast town of Stuart just before midnight with 120 mph (192 kph) winds, leaving a trail of devastation in areas that had little time to recover after being battered by Hurricane Frances on September 5.

Many damaged homes had been protected from the elements by little more than blue tarpaulin sheets. Several buildings damaged by Frances were demolished by Jeanne, emergency workers said.

An insurance industry group, Risk Management Solutions, estimated insured losses from Jeanne at $4 billion to $8 billion (2.2 billion to 4.4 billion pounds).

As the wind and rain died down, rescue workers fanned out to search for potential victims.

"Today the focus is on life and death," said Florida emergency co-ordinator Mike DeLorenzo. "We need to get in there and find out what the situation is as soon as we can."

Hardest hit were Martin, Indian River and St. Lucie counties on Florida's central Atlantic coast, Bush said.

"I think I can safely say they all took more than they wanted ... All the damage in the three counties is significant," the governor said.

Towns along the coast were littered with tree limbs, twisted signs, scraps of aluminium, strips of roof and other debris. In some areas, cars stood in fender-deep water and mobile homes peaked out of newly formed, muddy lakes.

Up to 3 million of Florida's 17 million people had been urged to evacuate trailer parks, islands and flood-prone areas, but many, emboldened by having survived Frances or weary after six weeks of hurricane alerts, decided to ride it out at home.

Jeanne weakened to a tropical storm as it barrelled northwest toward the Tampa area, threatening inland Florida with flooding rain. Forecasters expected it to weaken further and turn north, moving into Georgia yesterday.

The south end of Hutchinson Island, off Stuart, was submerged, and bridges to the island were impassable because of wave damage, said Linette Trabulsy of St. Lucie County emergency management. Two nuclear power reactors on the island had been shut down before the storm and were safe, said a spokeswoman for Florida Power & Light Co.

At the height of the storm, 300 people with special needs, many in wheelchairs or clutching oxygen bottles, had to be evacuated from an emergency shelter in Brevard County after Jeanne ripped off part of the roof, said Jenna Heller, a spokeswoman for the county's emergency management agency.

Martin County emergency operations spokeswoman Jackie Williams said several shelters suffered minor damage and leaks, but evacuees were able to stay in them. "We just had to move them from room to room," Williams said.

Stuart Mayor Jeff Krauskopf said a hospital lost half its roof but the 50 patients inside were safe.

The winds flipped over three small planes at Palm Beach International Airport and battered a hangar already damaged by Frances, said airport spokeswoman Lisa De La Rionda.

In the last six weeks, Florida has been hit by hurricanes Charley, which slammed into the southwest Gulf Coast on August 13, Frances on September 5, and Ivan, which roared onto the Gulf Coast between Florida and Alabama on September 16.

Those storms left 108 people dead in the United States and up to $17.8 billion in insured losses.