Fear spread up the southeast coast today as Hurricane Floyd, one of the most dangerous storms of the century, pounded the Bahamas and roared toward the Florida shore and beyond. Before it turned to the north and appeared to be headed to the Carolinas, the storm threatened everything from the nation's four space shuttles housed at the Kennedy Space Center on the central Florida coast to the graceful antebellum homes of Savannah, Ga.

Emergency officials in Florida, Georgia and South Carolina cranked into high gear as forecasters warned that the mammoth hurricane could ravage the Florida shore, then make a direct and devastating hit in the Savannah area or somewhere near Charleston.

But by midnight Tuesday, Floyd had turned, and the predicted landfall was revised to between 5 and 6 a.m. Thursday in between Myrtle Beach, S.C., and Wilmington, N.C. North Carolina Gov. James B. Hunt ordered the state's barrier islands evacuated, saying, "Don't tempt it."

Areas from Fort Pierce, Fla., all the way to the North Carolina-Virginia border were under a hurricane warning, and a hurricane watch was posted for the Virginia coast from North Carolina to Chincoteague, including the Chesapeake Bay. High surf was predicted as far north as Cape Cod. But populous southern Florida, including the Miami area, was spared Floyd's wrath.

The storm's approach Tuesday had spawned massive evacuations, as the 800,000 residents of the South Carolina coast and 500,000 residents of the Georgia shore, including the entire city of Savannah, were ordered to flee their homes. About 1.7 million Floridians had been urged Monday to seek safer ground.

The governors of South Carolina -- where residents still shudder at the memory of Hurricane Hugo's destruction in 1989 -- Georgia, North Carolina and Virginia all joined Florida in declaring states of emergency, which, among other things, allows the governors to call up the National Guard.

Traveling in New Zealand, President Clinton cut short his trip to return to Washington and issued preemptive disaster declarations for Florida and Georgia.

None of these measures seemed too extreme as the powerful storm continued its relentless -- and still somewhat uncertain -- path. Although its winds had dropped to 140 mph Tuesday afternoon from an awe-inducing high of 155 mph, it was still a steady Category 4 storm, on a scale of 1 to 5, capable of producing major devastation.

"Someone is going to bear the brunt of this hurricane and it is going to be devastating," said Todd Kimberlain, a meteorologist with the National Hurricane Center in Miami. "We don't think it's going to just go out to sea."

In the Bahamas, which Floyd pummeled on Tuesday, reports were still ominously sketchy about the extent of damage, although no fatalities had been reported. Ham radio operators said that wind gusts had reached 135 mph in Eleuthera, a mile-wide island with 11,000 residents that took a direct hit, according to news reports, and in the capital city of Nassau, shrieking winds ripped off awnings and roofs, and caused street lights to explode. Some inkling of the fear brought by the horrific storm was evident in the small, scared voice of a Nassau man on the radio who reportedly said, "I'm living on the mercies of the Lord."

As Floyd turned its attention toward the eastern United States, evacuation shelters in the three states began to fill up with nervous, hollow-eyed people; busloads of U.S. Marines were swiftly removed from South Carolina's Parris Island; interstate highways turned into virtual parking lots as evacuees inched away from Jacksonville, Fla., and Savannah. On Georgia's remote Cumberland Island, National Park Service workers hurried to round up 89 oblivious campers, and in Orlando, the unthinkable happened: Disney World closed for the first time in its 28-year history.

On Route 80 in Georgia, Valerie Morsell pulled her white station wagon to the side of the road. She was frantic, having driven across the state to Savannah from Dallas, Ga., to rescue her elderly father. Her father, Chuck Sheldon, 77, insisted on driving his own truck. They left in a convoy but were separated on the highway. "He just took off," she said, nearly in tears. Pooler, Ga., Police Officer Powell Harrelson radioed his dispatcher but warned Morsell that finding one vehicle among the thousands would be difficult.

Curfews were ordered up and down the coast; police officers shooed surfers out of the rough waves at Miami Beach; tempers flared at some gasoline pumps as the long wait for Floyd began to play on nerves. At a Home Depot in Hollywood, Fla., shoppers fidgeted in long, anxious lines for a reported eight hours to purchase plywood and other supplies.

Along the Florida coast, where Floyd had been forecast to send hurricane-force winds and strong storm surges from Palm Beach to Jacksonville, the skies became grayer as Tuesday progressed and the sea grew choppier. Sudden winds tossed the tops of palm trees, and heavy rain was reported from West Palm Beach north to Cape Canaveral.

At 2 a.m., Floyd was 125 miles east-southeast of Cape Canaveral, moving northwest at 13 mph. Hurricane force winds extended 120 miles from the eye, and tropical storm grade winds could be felt as far as 290 miles from the center. Daytona Beach and St. Augustine were receiving tropical-force gusts, the hurricane center said.

Ken Davis of the Georgia Emergency Management Agency said evacuations ordered at midday Tuesday instantly turned the coastal highways into jam-packed, slow-moving evacuation routes. Traffic on Interstate 16, which runs to the coast from Macon, stalled, and Interstate 75, which cuts through the middle of the state, was at twice its capacity. He had never seen anything like it, he said.

In South Carolina as well, the ordered evacuations brought a terrifying new urgency to coastal residents who had hoped against hope that they could sit this one out.

"We are reiterating the fact that this is a very dangerous storm, the likes of which we haven't seen since Hugo," said Christie Johnson of the South Carolina Emergency Preparedness Agency, evoking the fearsome 1989 storm that caused $10 billion in damage and took 21 lives as it cut a swath inland through the Carolinas. "And the thing is, Floyd may be worse."

No one could say what miseries awaited the residents as the storm drew closer. But long before its arrival, Floyd was delivering plenty of anxiety and low-level misery to residents from Florida to the Carolinas.

Bill Hutchinson, for example, was stuck on U.S. Route 1 Tuesday afternoon in 90-degree heat in a mini-caravan of seven family members and friends in four vehicles who were trying desperately to put Neptune Beach, near Jacksonville, behind them. They were hoping to make it to Valdosta, Ga., the nearest place they could find a motel to accommodate them.

"We've been in this traffic jam an hour and a half and if we've gone 10 miles, I don't see how," said Hutchinson, 44, manager of a shipyard that repairs Navy ships. "It's worse than D.C. at rush hour."

Special correspondent Catharine Skipp in Miami, staff writer Craig Timberg in Richmond and special correspondent John P. Martin in Georgia contributed to this report.

CAPTION: HITS ON THE COAST (This graphic was not available)