While most attention was on Hurricane Gustav in the Gulf of Mexico, Hanna has slowly organized over the last few days, becoming a hurricane Monday afternoon.
The National Hurricane Center has Hanna coming ashore as a minimal hurricane Friday near Savannah, Ga., but forecasters warned the track could swing as far south as Miami or as far north as North Carolina's Outer Banks.
The hurricane was over the southeastern Bahamas on Monday and could still be in the island chain Thursday, said Chris Landsea, science operations officer at the hurricane center.
"It's really going to move very slowly," Landsea said.
The track could remain uncertain for days, said Mark Bacon, a meteorologist at the National Weather Service office in Wilmington, N.C.
"When these storms are not moving -- and this one is barely moving -- until they make that turn to the northwest up toward land, the track forecast is really tough to nail down," Bacon said.
Emergency officials across coastal South Carolina worked Labor Day, joining a conference call with state officials to get geared up in case Hanna strikes, said Joe Farmer, spokesman for the South Carolina Emergency Management Division.
"We don't have any intention on letting this sneak up on anybody," Farmer said.
Savannah and nearby Hilton Head Island haven't been hit directly by a hurricane since 1893, when the Sea Islands Hurricane killed anywhere from 1,000 to 2,500 people.
Farmer said even though the region has been spared for more than 100 years, he thinks officials will be ready.
"Their preparedness level is very high," Farmer said.
"Although they haven't been hit directly on, they are fully aware there is a hurricane out there and they are ready to do what is needed."
The Georgia Emergency Management Agency planned to begin staffing its operations center around the clock Tuesday morning, spokeswoman Kandice Eldon said.
The center brings together officials from state and federal government and organizations like the Red Cross to plan for disaster response, she said.
A spokesman for South Carolina Gov. Mark Sanford said the governor was in Minnesota for the Republican convention but prepared to return home if the threat to the state increased.
North Carolina Gov. Mike Easley said state officials have been preparing for Hanna and urged residents to do the same.
"We can't get caught waiting for the storm to make up its mind where it will go," Easley said in a statement.
At Ace Hardware of Hilton Head, owner David Leick said Monday he was enjoying what might be the last quiet day for a while if the forecasts for Hanna come true.
"It's a holiday. We're a beach area, so people are more concerned with being outdoors," Leick said. "If the forecast stays the same, I bet it will pick up soon."