CEDAR KEY, Fla — Florida residents living in vulnerable coastal areas were ordered to pack up and leave Tuesday as Hurricane Idalia gained steam in the warm waters of the Gulf of Mexico and threatened to unleash life-threatening storm surges and rainfall.

Idalia had strengthened to a Category 2 system on Tuesday afternoon with winds of 100 mph. The hurricane was projected to come ashore early Wednesday as a Category 3 system with sustained winds of up to 120 mph in the lightly populated Big Bend region, where the Florida Panhandle curves into the peninsula. The result could be a big blow to a state still dealing with lingering damage from last year’s Hurricane Ian.

The National Weather Service in Tallahassee called Idalia “an unprecedented event” since no major hurricanes on record have ever passed through the bay abutting the Big Bend.

On the island of Cedar Key, Commissioner Sue Colson joined other city officials in packing up documents and electronics at City Hall. She had a message for the almost 900 residents who were under mandatory orders to evacuate. More than a dozen state troopers went door to door warning residents that storm surge could rise as high as 15 feet.

“One word: Leave,” Colson said. “It’s not something to discuss.”

Not everyone was heeding the warning. Andy Bair, owner of the Island Hotel, said he intended to “babysit” his bed-and-breakfast, which predates the Civil War. The building has not flooded in the almost 20 years he has owned it, not even when Hurricane Hermine flooded the city in 2016.

“Being a caretaker of the oldest building in Cedar Key, I just feel kind of like I need to be here,” Bair said. “We’ve proven time and again that we’re not going to wash away. We may be a little uncomfortable for a couple of days, but we’ll be OK eventually.”

Tolls were waived on highways out of the danger area, shelters were open and hotels prepared to take in evacuees. More than 30,000 utility workers were gathering to make repairs as quickly as possible in the hurricane’s wake. About 5,500 National Guard troops were activated.

In Tarpon Springs, a coastal community northwest of Tampa, 60 patients were evacuated from a hospital out of concern that the system could bring a 7-foot storm surge.

“You do not have to leave the state. You don’t have to drive hundreds of miles,” Florida Gov. Ron DeSantis said Tuesday morning at the state’s emergency operations center. “You have to get to higher ground in a safe structure. You can ride the storm out there, then go back to your home.”

Idalia’s initial squalls were being felt in the Florida Keys and the southwestern coast of Florida on Tuesday afternoon, including at Clearwater Beach. Workers at beachside bars and T-shirt shops boarded up windows, children skim-surfed the waves and hundreds of people watched the increasingly choppy waters from the safety of the sand.

After landing in the Big Bend region, Idalia is forecast to cross the Florida peninsula and then drench southern Georgia and the Carolinas on Thursday. Both Georgia Gov. Brian Kemp and South Carolina Gov. Henry McMaster announced states of emergency, freeing up state resources and personnel, including hundreds of National Guard troops.

“We’ll be prepared to the best of our abilities,” said Russell Guess, who was topping off the gas tank on his truck in Valdosta, Georgia. His co-workers at Cunningham Tree Service were doing the same. “There will be trees on people’s house, trees across power lines.”

At 5 p.m. EDT Tuesday, Idalia was about 195 miles southwest of Tampa, the National Hurricane Center said. It was moving north at 16 mph.

In Cuba, meanwhile, most of the western provinces that Idalia thrashed with heavy rains on Sunday and Monday are underwater, President Miguel Diaz-Canel said. The areas affected include the tobacco-producing province of Pinar del Rio.

“The priority is to reestablish power and communications and keep an eye on the agriculture: Harvest whatever can be harvested and prepare for more rainfall,” he told government officials.

More than 10,000 people had been evacuated to shelters or stayed with friends and relatives as up to 4 inches of rain fell. More than half of the province was without electricity.

Cuban state media did not report any deaths or major damage.