With Hurricane Frances prompting Gov. Mark Sanford to consider the first wide-scale coastal evacuation since the Hurricane Floyd debacle in 1999, it’s time to see how much South Carolina’s leaders and its residents learned from the past.

A slight shift of the storm track to the west Wednesday allowed hope that evacuations might not be necessary. The National Hurricane Center forecasts that the storm will make landfall in central to northern Florida on Saturday. But veterans remember that Floyd took a similar path before turning up the coast, and some computer models predict Frances will do the same.

But since Floyd, the state has put together a hurricane plan, detailing every aspect of an evacuation. Emergency personnel have practiced reversing lanes to funnel more traffic away from the coast. State officials hope residents who evacuated in 1999 learned from the experience.

Sanford has been conducting regular conference calls with state emergency officials from the Republican National Convention in New York, said spokesman Will Folks. The decision on when Sanford will return to the state, much like the decision whether to evacuate the coast, depends on the projected path of the storm.

The preferred scenario is to have evacuees out of the storm’s path at least 12 hours before it arrives. The state hurricane plan estimates it will take 22 to 26 hours to evacuate the major coastal areas during a busy Labor Day weekend. If Frances bends toward South Carolina, it likely would reach the state on Sunday.

Adding it up, an evacuation decision likely could be made Friday.

As he did in declaring a targeted mandatory evacuation for Hurricane Charley last month, Sanford will seek input from weather experts, emergency personnel and coastal leaders.

Tourism experts calculated the mandatory evacuation for Charley cost coastal businesses $30 million in revenue. They seek a balance between safety and commerce when considering evacuations.

Two documents offer the governor evacuation guidelines. The state hurricane plan, which lists such details as when to deploy portable road signs and when to take water to interstate comfort stations, and a study of the Floyd evacuation by University of South Carolina researchers.

The hurricane plan, updated each year, now calls for lane reversals on I-26, U.S. 501 in the Pee Dee and U.S. 278 in Beaufort County, creating four lanes of traffic leading away from the coast on those routes.

The USC study recommended that state officials make decisions that prompt gradual evacuations, not oh-my-gosh-we-gotta-leave reactions, said Susan Cutter, who coordinated the study.

“Waiting until the last minute is not a good idea,” Cutter said. “We found that everyone left within a six-hour window, which contributed to the evacuation problems.”

During Floyd’s evacuation, I-26 turned into a parking lot, and some evacuees reported the usual two-hour trip to Columbia took 18 hours. Political experts believe Gov. Jim Hodges’ delayed decision to reverse lanes on I-26 contributed to his loss in the 2002 election.

Residents and visitors can do their part by asking themselves: “Am I really in harm’s way? How far do I need to go? Does my family really need to leave in more than one vehicle?”

“About one-quarter of the families that evacuated (in Floyd) took two or more cars, even if they had a relatively small household,” Cutter said. “Some took as many cars as they owned with as many drivers has they had.”

Plenty of people who evacuated didn’t really need to, a phenomenon called “shadow evacuation.” People who live outside the designated evacuation zone head for the hills because they hear the media announcements but don’t really understand them, Cutter said.

State officials “need to be very specific in their targeted areas for evacuation,” Cutter said. “And it’s incumbent upon the media to make those targeted areas clear.”

Emergency officials agree with the USC study’s recommendations. But they also realize they need to adapt to situations.

Sanford tore up the guidebook when Hurricane Charley made an unexpected jog to the north. He ordered a mandatory evacuation beginning at 8 p.m. The plan does not recommend night-time evacuations.

No major accidents and few injuries were reported as the Category 1 hurricane made landfall in Georgetown County.

Charley, however, was only a pop test. Most of the evacuees east of U.S. 17-Business were tourists. Locals accustomed to Category 1 storms stayed put. The Floyd study noted that many of those people will flee a more powerful Category 3 storm like Frances.

Reach Holleman at (803) 771-8366 or jholleman@thestate.com.