Hurricane Ian made its second landfall on Friday - hitting South Carolina after carving a broad path of destruction across Florida earlier in the week.
Ian swept ashore as a Category 1 storm near the historic Georgetown shortly before 2.30pm on Friday afternoon US time, with top sustained winds of 85mph, says the US National Hurricane Center.
It was expected to bring life-threatening flooding, storm surges and winds to South Carolina, Georgia and North Carolina, with officials in all three states warning residents to prepare for dangerous conditions.
The storm hit Florida’s Gulf Coast as a powerful Category 4 hurricane with 150mph winds on Wednesday, flooding homes and leaving nearly 2.7 million people without power.
Before it reached South Carolina on Friday, sheets of rain whipped trees and power lines and left areas of central Charleston underwater by midday in the US.
A popular pier in the beach community of Pawleys Island collapsed and floated away, while in Myrtle Beach, waves were pushing against the city’s boardwalk tourist area, flowing over where thousands of tourists typically fill the wide sandy stretch.
Ian left destruction in its wake after it came ashore on Florida’s Gulf Coast as one of the strongest storms ever to hit the US.
Hurricane Ian - In pictures
The storm flooded areas on both of Florida’s coasts, tore homes from their foundations, demolished beachfront businesses and left more than 2 million people without power.
There have been reports of at least 21 deaths in Florida, Kevin Guthrie, director of the state’s Division of Emergency Management, said at a morning briefing. He stressed that some of those reports remain unconfirmed.
Among those killed were an 80-year-old woman and a 94-year-old man who relied on oxygen machines that stopped working amid power outages, as well as a a 67-year-old man who was waiting to be rescued, and died after falling into rising water inside his home, authorities said.
A huge search and rescue operation remained underway in Florida on Friday as President Joe Biden warned of “substantial loss of life”.
Rescue crews piloted boats and waded through flooded streets to save thousands of Floridians trapped in their homes.
The storm made made landfall on Wednesday in Florida near Cayo Costa as an “extremely dangerous” category 4 storm with winds of 150 mph leaving more than two million people without power.
A storm surge as high as 12ft crashed into the coastline turning streets into rivers sparking warnings of “life-threatening” flooding.
The town of Fort Myers Beach was almost submerged by floodwaters, and some homes could be seen floating downstream, along with cars.
President Biden said a search and rescue operation was underway to help people who were left “in desperate shape” by the storm.
He said: “This could be the deadliest hurricane in Florida’s history.
“The numbers are still unclear but we’re hearing reports of what may be substantial loss of life.”
The destruction began to come into focus a day after Ian made landfall in Florida.
The storm flooded homes on both of the state’s coasts, cut off the only bridge to a barrier island, destroyed a historic waterfront pier and knocked out electricity to 2.5 million Florida homes and businesses. At least one man was confirmed dead.
“We’ve never seen storm surge of this magnitude,” Florida governor Ron DeSantis told a news conference.“The amount of water that’s been rising, and will likely continue to rise today even as the storm is passing, is basically a 500-year flooding event.”
Though downgraded to a tropical storm by Thursday morning, the National Hurricane Centre said storm surge and flooding rains remained a threat as Ian crept across the Florida peninsula and emerged in the Atlantic Ocean.
Sheriffs in south-west Florida said 911 centres were inundated by thousands of stranded callers, some with life-threatening emergencies.
The US Coast Guard began rescue efforts around daybreak on barrier islands near where the Ian struck, Mr DeSantis said. Fire departments fanned out in flooded areas as well.
In the Orlando area, Orange County firefighters used boats to reach people in a flooded neighbourhood.
At an area nursing home surrounded by water, patients were carried on stretchers across floodwaters to a waiting bus.
Lee County Sheriff Carmine Marceno said his office was scrambling to respond to thousands of 911 calls, but many roads and bridges in Fort Myers and the surrounding area remain impassable.
“It crushed us.” Mr Marceno told ABC’s Good Morning America. “We still cannot access many of the people that are in need.”
Emergency crews sawed through toppled trees to reach stranded people. Many in the hardest-hit areas were unable to call for help amid widespread electrical outages.
A chunk of the Sanibel Causeway fell into the sea, cutting off access to the barrier island where 6,300 people normally live.
In Port Charlotte, a hospital’s emergency room flooded and fierce winds ripped away part of the roof, sending water gushing down into the intensive care unit.
Large swathes of southern Florida were left without power with 2.2 million left without electricity, according to PowerOutage.us.
About 2.5 million people were ordered to evacuate south-west Florida before Ian hit yesterday afternoon.
Ian was expected to dump 12-18in (30-45cm) of rain across a broad area including Tampa, Orlando, and Jacksonville.