TYBEE ISLAND, Ga. — On Wednesday night, Georgia Gov. Nathan Deal urged residents of six coastal counties to voluntarily evacuate with the threat of Hurricane Matthew approaching the region.

“The National Hurricane Center predicts Hurricane Matthew will include excessive rainfall, strong winds and potential flooding,” the governor said. “Because of this, I’m encouraging a voluntary evacuation for residents in Chatham, Bryan, Liberty, McIntosh, Glynn and Camden Counties.”

More than 522,000 people populate the six coastal counties. An evacuation hasn’t been seen in coastal Georgia in 17 years.

Deal is encouraging residents to remain calm and make responsible decisions while he monitors the storm’s path. He also expanded the state of emergency to include the 17 counties in southeast Georgia, for a total of 30 counties.

On Tybee Island, home to Georgia’s largest public beach, Loren Kook was loading up his pickup truck with suitcases and a computer late Wednesday afternoon. He and his wife were trying to decide whether to board up their windows overlooking the marsh grasses of Horsepen Creek before hitting the road to metro Atlanta.

“It seems like a lot of the longtime residents are staying,” said Kook, who moved to the coast four years ago. “I’ve never sat through a Category Whatever. I’ll watch it on TV.”

The National Hurricane Center placed all 100 miles of the Georgia coast under a hurricane watch Wednesday, saying hurricane winds of 74 mph or greater could reach the state by late Friday.

Chatham County officials urged roughly 30,000 residents living on the islands east of Savannah to evacuate by Thursday morning. Further evacuation orders for Savannah and other inland communities could come later.

Meanwhile, Glynn County announced a voluntary evacuation for about 17,000 people on St. Simons Island, Sea Island, Jekyll Island and Little St. Simons Island.

Officials said they were concerned that even if Matthew stays offshore, it will likely pass close enough to blast homes near the ocean and coastal waterways with several feet of storm surge. Tybee Island is linked to the mainland by a single road that can flood if inundated with water at high tide.

“We don’t want people on Tybee Island panicking in the middle of the night and deciding they’re going to try to leave the island” once the hurricane arrives, said Al Scott, chairman of the Chatham County commission.

The Georgia coast hasn’t seen such a hurricane evacuation since a near-miss with Hurricane Floyd in 1999. No storm has made direct landfall along the state’s coastline since Hurricane David in 1979, and the last time Georgia saw a direct hit from a Category 3 or greater storm was in 1898. Category 3 hurricanes have winds in excess of 110 mph.

Tybee Island City Hall, the public library and several businesses had their windows boarded Wednesday. The annual celebration of Pirate Fest, known to bring thousands of visitors to the island, was canceled ahead of what was supposed to be a busy weekend for offseason tourism.

Don Crum and his wife, who own Bowie Seafood on the island, were closing for the rest of the week. Crum said he would probably lose up to $6,000 in sales but would rather make sure their business was protected.

“If we get 100 mph winds, I don’t want anything damaged,” Crum said after climbing a ladder to close storm shutters on the second story of his shop, which sells fresh shrimp and other seafood to locals and tourists. “It’s easier to do this rather than come back with the windows all blown up and have to clean up the mess. We’re preparing for the worst.”

Susan Deason, a Tybee resident for 30 years, was loading up kennels and pet food to get 14 dogs and cats off the island. She was enlisting six friends to help her drive them inland, possibly to Statesboro or to a friend’s house in Augusta.

“I hate the idea that this place may flood and everybody has to worry,” Deason said. “It’s the waiting that kills us. It’s not the actual hurricane.”

Associated Press writer Jonathan Landrum Jr. contributed to this report.