FORT MYERS BEACH, Fla. — Mitch Pacyna and his wife had weathered other hurricanes in their 27 years on this sandy stripe of barrier island and decided to ride out Hurricane Ian at home.

But as the monster storm began to mow down houses around them, Mr. Pacyna posted videos of the churning floodwaters sweeping away an open-air bar he had built. “WE’RE TERRIFIED!!” he wrote in a final Facebook post on Wednesday afternoon.

Mr. Pacyna, 74 — a gregarious fixture of beach life known to friends as “the mayor” — was killed as he and his wife, Mary Wojciechowski, who survived, tried to flee to safety during the storm, Michelle Schuline, his daughter, said. His death was part of a grim toll that began to emerge on Friday, as officials in Florida said that at least three dozen deaths had likely been caused by the storm — a toll they expected to rise.

“The building they were in was being torn apart,” Ms. Schuline said, recalling her father as a devoted Chicago Cubs and Blackhawks fan who had recently traveled to see his granddaughters graduate from high school and college. “They were trying to get to higher ground.”

Gov. Ron DeSantis described the island as “ground zero” in a briefing on Friday.

As southwestern Florida struggled to restore even basic functions like power and water, and rescue workers continued their search for people trapped or killed during the storm, Hurricane Ian hit South Carolina on Friday as a much weaker Category 1 storm, making landfall between Charleston and Myrtle Beach. Storm surge and flash flooding remained threats as Ian was quickly downgraded to a post-tropical cyclone, but initial damage reports were far less dire than what Florida experienced.

In places like Fort Myers Beach, Sanibel Island and Pine Island, just west of Fort Myers, an easygoing existence that once revolved around seashell hunts, shrimping, turtle-watching, taking in sunsets over the Gulf, and the ebb and flow of a seasonal tourist economy had been obliterated.

A search team combing buildings on Fort Myers Beach recovered at least one body on Thursday; on Friday, a paramedic spotted a woman’s body floating in the water off Pine Island, while Sanibel officials confirmed several storm-related fatalities there. Drinking water and food were scarce on Pine Island, whose only bridge to the mainland was impassable. And many residents were now uncertain about how long — if ever — it might take to recover.

“It looks like a bomb went off,” said Dana Gosford, a managing partner of Shucker’s, a century-old seafood restaurant and bar in Fort Myers Beach that was flattened by the storm. “We’re just — I don’t know if we’re going to be rebuilding at this point. We’re just still in shock.”

Hurricane Ian’s Category 4 winds and deadly rains hammered communities from Florida’s southwestern coast to the Orlando region, but it was this archipelago of barrier islands that took the most ferocious hit.

In Fort Myers Beach, whose streets jam when the population of about 5,600 swells to tens of thousands during the busy season, beach bars and restaurants that had survived Hurricanes Irma and Charley lay in ruins on Friday.

A fishing pier had been stripped to its concrete pilings. All that remained of some homes were the stairs leading up to what had once been a door.

After surveying the damage from the air, Jared Moskowitz, a former state emergency management director, estimated that 80 percent of Fort Myers Beach and Sanibel Island might need to be rebuilt. A causeway that had been Sanibel’s only road to the mainland was shorn apart by the storm, further isolating anyone who remained.

Mr. DeSantis, who earlier described the storm surge on the Sanibel as “biblical,” on Friday offered a sobering assessment of the toll.

“If a house just washes away into the ocean, into the water, with 155-mile-per-hour winds, if that person evacuated, that’s great,” Mr. DeSantis said. “If they didn’t, I don’t know how you survive that.”

Mr. DeSantis said on Thursday night that at least 700 people had been rescued, and later said rescuers had visited at least 3,000 homes in the worst-hit areas up and down the coast. He said that some residents who had survived the storm were declining the offers of rescue, insisting that even now they wanted to stay.

On Friday, some residents of Fort Myers Beach trickled back on foot, pulling wagons and carts over the Matanzas Pass Bridge in the hopes of salvaging what they could from what was once their homes. Some had no clue yet whether anything was left to salvage.

“What do you do when you don’t have a building to go back to?” asked Krissy Simone, who owns a spa and salon on Fort Myers Beach. She had been told that the floods reached near the top of her first floor.

Anita Cereceda, a former mayor of Fort Myers Beach who owns three boutiques, said the storm had obliterated many historic homes and businesses that predated sturdier concrete high-rises, demolishing what was left of beloved old traditional, wood frame cottages.

“There is devastation like no one has ever seen,” Ms. Cereceda said. “It is a sickening feeling to think your life’s work has been erased.”

On San Carlos Island, Darrell Hanson began the work on Friday of cleaning up his businesses — Salty Sam’s boat rentals and two restaurants. Storm surge had trashed his shop from floor to ceiling and left behind layers of slippery gray-brown mud.

His employees grabbed brooms while Mr. Hanson worked his phone to find someone — anyone — with heavy machinery.

“It’s a war zone,” Mr. Hanson said. “It couldn’t really be any worse.”

After spending the storm on the mainland, he still did not know how his home on nearby Sanibel Island had fared. He and other Sanibel residents wanted to ride out in a boat since the bridge was impassable, but the marina was so jammed with storm-tossed boats that Mr. Hanson did not think he could safely navigate from San Carlos Island.

In a mobile home park nearby on San Carlos, Tammy Clements, 57, had lost everything she owned, including her cat, Double Dip Oreo.

The floodwaters inside her trailer had reached her neck, and she was forced to swim to another neighbor’s trailer where she regained her strength by resting on a floating couch before setting out yet again to her boyfriend’s trailer. Her back and legs were bruised from the harrowing escape.

“I didn’t die,” she said, still astonished. Her dog, Nugget, had also survived.

As helicopters whisking people out of Fort Myers Beach thumped overhead, Ms. Clements and her boyfriend, Peter Neelon, 75, surveyed the damage inside his damp-smelling trailer, where the flood had left a mark three-quarters of the way up the wall. His television and car were both destroyed. He was air-drying underwear on a rack outside.

“I don’t know what I’m going to do,” Ms. Clements said, but she pointed at Mr. Neelon, who had bought her now-wrecked trailer for her. “He will make sure I won’t be homeless.”

On Pine Island, scenes of desperate rescue were still unfolding as volunteers with the Cajun Navy sought out addresses of people potentially in distress.

They rescued a 28-year-old man who rode out the storm with his mother, and a 98-year-old man who had been with his son and daughter-in-law when their house flooded. The older man shivered in the cold spray of the surf as the volunteer rescuers whisked him to the mainland.

Off the island, residents who had fled the storm have been turning to Facebook community groups and watching the news for word of whether their homes survived.

One resident, Kevin McVey, had not wanted to leave home but evacuated when his wife, Cheryl, insisted. They and their 20-year-old daughter left with the clothes on their backs, their dog and a couple of gas cans. They thought they would be gone for a few days, but now they did not know when they would be able to return since the bridge to the mainland was destroyed.

Ian was their first Florida hurricane.

On Friday, a neighbor managed to reach them by hiking to a cellphone hot spot near Matlacha, a quirky, pastel-hued community that was now heavily damaged. The McVeys had lost a lot of trees, but their home itself, which sits on the middle of the island about 12 feet above sea level, appeared undamaged.

Hilary Swift, Amanda Holpuch, Ruth Graham and Vimal Patel contributed reporting. Susan C. Beachy, Kitty Bennett and Kirsten Noyes contributed research.