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(CNN) Ian's vicious combination of winds, rain and storm surge caused at least a dozen deaths, flooded homes, cut off roadways and left millions of Florida residents without power Thursday as it again intensified into a hurricane in the Atlantic Ocean and barreled toward South Carolina.
Ian made landfall Wednesday afternoon in southwest Florida and was downgraded to a tropical storm, dropping heavy rain on central and northeast Florida throughout Thursday.
But it intensified into Category 1 hurricane Thursday afternoon and is forecast to make a second landfall in South Carolina on Friday, the National Hurricane Center said.
In southwest and central Florida, at least 15 people were reported dead so far due to the storm. At least 17 deaths have been reported in connection with Ian.
The death toll in Charlotte County was at least eight or nine, Charlotte County Commissioner Joseph Tiseo told CNN Thursday afternoon. About five people are believed to have died in Lee County, the sheriff there said.
One person who was in hospice care died in Osceola County, Emergency Management Director Bill Litton said. And a 72-year-old man in Deltona died overnight after going outside to drain his swimming pool during the storm, according to the Volusia County Sheriff's Office.
Sarasota County is reporting two hurricane-related deaths in the county, Sarasota County Sheriff PIO Kaitlyn Perez told CNN. Perez said the office did not have additional details on where the deaths took place or information on the deceased individuals.
Additionally, more than 2.3 million customers had no power Thursday evening, according to PowerOutage.US, and some drinking water systems have broken down completely or have boil notices in effect.
"This could be the deadliest hurricane in Florida's history," President Joe Biden said Thursday. "The numbers are still unclear, but we're hearing early reports of what may be substantial loss of life."
Florida State Fire Marshal Jimmy Patronis agreed, telling CNN Ian is shaping up to be the largest natural disaster in state history.
Florida residents assessing storm damage Thursday found collapsed buildings, ongoing flooding, downed power lines and impassable roads, including a key bridge connecting Sanibel and Captiva islands to Florida's mainland that has been washed out.
Approximately 40 people were taken off the Sanibel Thursday, 12 of whom were injured. Due to the damage to the causeway, first-responders are only able to get to the island by boat.
"The island is in rough shape," said Sanibel Police Chief Bill Dalton. "The power infrastructure is severely damaged. I would be surprised that there's a single structure on the island that hasn't been impacted by the storm."
Sanibel, in Lee County, "got hit with really biblical storm surge," Gov. Ron DeSantis said. Lee County Utilities issued a systemwide boil-water notice for all customers effective immediately due to the impacts of the hurricane, according to county officials.
"I just literally got out of a helicopter where I was able to take a complete tour of the entire county and there's really no words that I can say to tell you what I've seen," Lee County Sheriff Carmine Marcino said on CNN Thursday. "The Fort Myers Beach area, buildings, major, major homes and buildings completely washed away with vehicles in the water, vehicles in the bay, boats are upside down."
DeSantis said Thursday night that he surveyed damage in Charlotte County and Lee County.
"Some of the damage was indescribable," DeSantis said, adding he saw cars and homes floating in water. "The most significant damage I saw was on Fort Myers Beach. Some of the homes were wiped out, some were just concrete slabs."
About 200 people have been rescued by the Fort Myers Fire Department, Fort Myers Mayor Kevin Anderson told CNN Thursday night. The search and rescue operations appear to have come to an end in the city, according to Anderson.
Anderson said city has not had any fatalities. On Friday, the city will open "several food, water and ice distribution centers," Anderson said.
A boil water notice is in effect in the city of Fort Myers, according to a government statement posted Thursday. "This applies to water consumed for drinking, washing dishes, and brushing teeth among other uses," the statement said.
Lee County -- which includes Fort Myers --- issued a boil water notice Wednesday.
Officials in Kissimmee -- just south of Orlando -- told CNN Thursday evening "it's been a worst-case scenario" for the city.
"One of our hospitals here, Osceola Regional -- which is a trauma two-level center -- was surrounded by water this morning. Our rescues could not make entry," Bill Litton, Osceola County's emergency management director, told CNN Thursday evening.
Emergency responders conducted rescues by air, land and boat to save people trapped by the floodwaters. As of 2 p.m. Thursday, more than 500 people have been rescued in Charlotte and Lee counties, the Florida Department of Emergency Management said in a tweet. In Orlando, emergency responders navigating a street-turned-river told CNN they had conducted at least 200 rescues since early Thursday morning.
The US Coast Guard's 7th District rescued 68 people Thursday, which is included in the 700 state-wide rescues the governor reported Thursday, according to Rear Adm. Brendan McPherson.
Florida First Lady, Casey DeSantis, said Thursday she launched the Florida Disaster Fund to assist in rescue efforts. The fund raised more than $10 million within 24 hours of its launch, she said.
The rescue efforts come a day after Ian came ashore near Cayo Costa as a Category 4 hurricane with 150-mph winds, making it one of the strongest storms ever to make landfall on Florida's west coast. The storm cut a path from near Fort Myers in the southwest across to the eastern part of the state, and its combination of wind, rain and storm surge caused flooding that DeSantis called "a 500-year flood event."
Here are the latest developments:
• Hurricane warnings for South Carolina: Hurricane warnings are in place for the entire coast of South Carolina. In addition, Tropical Storm warnings are in place from Jupiter, Florida, up the east coast to Duck, North Carolina.
• Record-high storm surges: Ian's storm surge hit up to 12 feet in some places in western Florida. On Thursday morning, a storm surge warning -- meaning life-threatening surges could hit -- was in place for a coastal stretch from northeastern Florida into an area north of Charleston, South Carolina.
• More than a foot of rainfall: Lehigh Acres near Fort Myers got 14.42 inches of rain, and Warm Mineral Springs near Port Charlotte got 11.05 inches. Up to 30 inches of rain may have fallen in parts of Florida by storm's end, forecasters say.
Sunrise on Thursday gave Florida residents their first look at Ian's overnight wrath -- and the results were not pretty.
As Ian pushed inland, ocean water piled up onshore Wednesday -- 12 feet in some places -- and 150-mph winds whipped. 911 call centers in several counties were inundated.
Scott Carlos, who rode out the storm in his fourth-story Fort Myers condo, saw waves of water crash into homes across the street, up to their roofs, he said. Roads are littered Thursday with washed-out vehicles, he told CNN on Thursday.
"Everybody's garages basically just gave out. ... Cars are everywhere, smashed up in the street. There's debris everywhere," he said.
As Ian continued moving northeast, heavy rain and flooding has been reported in the Orlando area, where 8 to 12 inches of rain had already fallen and up to 4 more inches of rain was expected. In Orlando, a reporter for CNN affiliate WESH rescued a woman after seeing her trying to drive through floodwaters, carrying her on his back in waist-high water to dry ground, WESH video showed.
In Fort Myers -- where about 90% of electric customers were without power -- Fire Chief Tracy McMillion told residents to stay inside, and to stay hopeful. "We're coming for you, be encouraged," he told residents Wednesday night.
The city's downtown streets were flooded Wednesday with almost 4 feet of water, Mayor Kevin Anderson told CNN.
Thomas Podgorny was trapped in his two-story home in Fort Myers with three others, watching vehicles float away outside and worrying about others who did not evacuate, he told CNN Wednesday evening.
"I've lost my house. I have water and gas flowing through my bottom floor," he said. "My neighbors have very little breathing room in their one-story house."
One couple there was trapped in their home when the ceiling caved in.
"Something is dripping on me," Belinda Collins recalled her partner saying. "He got up, and the ceiling -- the family room ceiling -- caved in." They called 911 and were waiting for a call back about when it would be safe to leave, they said.
In Port Charlotte, the storm tore off the roof above a hospital's ICU with patients inside Wednesday, forcing staff to move them to a post-operation recovery area, Dr. Birgit Bodine, an internal medicine specialist at the facility, told CNN.
Water gushed down stairwells to other floors, and other patients needed to be moved either to beds in hallways or to a different, dry wing of the hospital.
"We still have water in hallways that we're still sloshing through," but patients are safe in dry beds, and as many as possible were transferred to the dry wing, Bodine told CNN Thursday morning.
People in nearby Collier County, which includes Naples, were also trapped in their homes, calling for help, after electricity went out. In Naples, half the streets were not passable Wednesday because of high water, officials said.
"Some are reporting life threatening medical emergencies in deep water. We will get to them first. Some are reporting water coming into their house but not life threatening. They will have to wait. Possibly until the water recedes," the Collier County Sheriff's Office said Wednesday evening.
Complicating matters, neighboring Lee County's 911 system was down and calls were being rerouted to Collier County, Chief Stephanie Spell told CNN. "At this point the majority of our 911 calls are water rescues," Spell added.
In Sarasota County, sheriff's deputies and fire crews had a backlog Thursday morning of more than 500 calls for help to respond to, the county sheriff's office said. Deputies were "responding to the highest priority calls" that still were in the queue Thursday morning, the office said.
Residents in parts of Pasco County were also asked to boil their tap water as the water distribution system in the area lost pressure and a water main ruptured.
In Manatee County, residents were asked to limit flushing, showering, doing dishes and laundry due to power outages impacting the system.
In Cape Coral, authorities were getting reports of significant structural damage across the city, Ryan Lamb, the city's fire chief and emergency management director, told CNN.
DeSantis has asked President Biden to approve a major disaster declaration for all 67 counties in the state, his office said in a news release. DeSantis is also asking Biden to grant FEMA the authority to provide 100% federal cost share for debris removal and emergency protective measures for the first 60 days from Ian's landfall.
With Ian again a Category 1 hurricane, a state of emergency was declared in Charleston County Thursday.
The hurricane is expected to hit South Carolina Friday near or just after these high tide times in the 11 a.m. hour. It's currently located about 240 miles south of Charleston and is moving toward the north-northeast at 10 mph, according to the hurricane center.
"We are looking at an early afternoon landfall," said CNN Meteorologist Tom Sater. "The entire southeastern coastline is pretty much going to be inundated with a surge again. It's not going to be what we saw in southwest Florida, but in Charleston you toss in ... 7 feet of a surge, the entire downtown historic area is flooded."
Coastal cities along the East Coast like Jacksonville, Florida, Savannah, Georgia, and Wilmington, North Carolina, could see anywhere from 2-7 feet of storm surge, Sater said.
South Carolina Gov. Henry McMaster said the biggest variable with Hurricane Ian may be "human reaction" to the storm.
"It's people failing to take the necessary precautions. That's the real danger that we have, is human error," McMaster said. "Doesn't make much difference whether this comes in at hurricane strength or below at storm strength or somewhere on the line, cause it's going to be blowing strong winds and it's going to be all over the state at different levels."
The US Geological Survey coastal change forecasts released Thursday predicts waves and surges will likely cause 11% of South Carolina's dunes and 1% of Georgia's dunes to be continuously covered by ocean water.
"This is the most severe type of storm effect on coastal beaches, with flooding behind the dunes that may impact coastal communities," a news release from the USGS said.
Additionally, 43% of South Carolina's dunes and 24% of Georgia's dunes are expected to be overwashed by Ian. This means sand will be pushed inland, resulting in changes to the coastal landscape that could block roadways.
"Overwash can reduce the height of protective sand dunes, alter beach profiles and leave areas behind the dunes more vulnerable to future storms," the release said.
Correction: An earlier version of this story had the incorrect location for storm witness Scott Carlos. He was in Fort Myers, Florida.