CHARLESTON, S.C. - The extended forecast for Hurricane Frances had the powerful Category 4 storm tracking more to the north on Tuesday - bad news for South Carolinians who already have weathered encounters with four storms in the past month.

Members of the South Carolina National Guard were put on alert that they might be needed for evacuations Labor Day weekend if Frances takes aim at the state.

"This is a very, very serious and a potential killer hurricane," said Joseph P. Riley Jr., the mayor of this city hammered by Hugo's 135 mph winds 15 years ago. "It appears it's going to make landfall somewhere. It appears it is not going out to sea."

Emergency officials monitored Frances closely even as the cleanup continued from Sunday's Tropical Storm Gaston.

Frances, spinning near Puerto Rico, had 140 mph winds - 5 mph stronger than Hugo's when it devastated Charleston 15 years ago.

The potential five-day track area for Frances included the entire state of South Carolina and most of Georgia.

The late morning advisory from the National Hurricane Center had the storm coming ashore near Jacksonville, Fla., on Sunday. But the forecast warned that track errors for five-day forecasts average 375 miles.

"The prudent course is for people in this area to act in their preparations as if it was going to come here," Riley said. "I'm not saying it's going to. But it's so big and the damage it could do is so huge, that we need to be very, very careful."

State emergency officials worried people might not monitor the storm as the Labor Day holiday weekend approached.

"It's going to make it tougher for everyone who planned to vacation along the coast of this state and Georgia and North Carolina and Florida," said Joe Farmer, a spokesman for the state Emergency Management Division. "What we really need for people to do is stay tuned to this event."

Farmer said that, with Frances threatening the entire Southeast as Hurricane Floyd did in 1999, people should realize there could be evacuations in a wide area.

"State government is paying very, very close attention. We want the public to do that also, especially with a holiday weekend coming up," he said.

The state Department of Public Safety planned media briefings in Charleston and Beaufort on Wednesday to remind residents about plans for lane reversals for hurricane evacuations.

"There certainly is concern about evacuation," said Charleston city spokeswoman Barbara Vaughn. "Even if it came in at Jacksonville, we would probably get tropical storm force winds."

Crews building the $632 million cable-stayed Ravenel Bridge over the Cooper River, the most expensive bridge project in state history, planned to work only Tuesday and Wednesday before battening down the bridge again.

They had to secure the building site just last weekend as Gaston came ashore.

This week, with the possibility of Frances hitting, they only unpacked materials need for a few days of work, said Bobby Clair, the Department of Transportation engineer overseeing the project.

"We should be secured for the hurricane force winds we would expect although it does require quite a bit of preparation," he said. "We only opened up materials and had materials delivered that we could put in place this week."

Emergency officials in Horry County urged residents to check hurricane kits which should include items such as canned food, water, battery-powered radios and clothing.

Labor Day is a busy tourist weekend on the Grand Strand. About 70 percent of the Myrtle Beach area's hotel rooms have been booked for the long holiday weekend, according to Coastal Carolina University's Center for Economic Development.

That figure could drop, however, depending on the track of the storm.

August was a busy month for tropical weather in South Carolina.

First, Alex threatened the state before moving northeast and slipping across the Outer Banks of North Carolina.

Bonnie spun into the state through the backdoor, coming northeast from the Gulf of Mexico. Hurricane Charley made a second landfall in South Carolina as a weak hurricane after hammering southwest Florida.

Then Sunday, Gaston hit the state with near-hurricane force winds. And the cleanup from the latest storm is still going on.

Schools opened again in the Charleston area and damage continued to be tallied. As of Tuesday afternoon, an estimated $6.3 million in 3,100 insurance claims had been reported, most of them in Charleston County.

After Gaston poured rains estimated at 13 inches in some places, creeks and rivers continued to rise.

Black Creek near Quinby in Florence County was about 2.5 feet above its flood stage of 10 feet Tuesday morning.

The creek waters, which were nearing several homes, were expected to crest at 14 feet on Wednesday, according to the National Weather Service.