Hurricane Ian starts lashing South Carolina after leaving at least 21 reported dead and millions without power across Florida

© Wilfredo Lee/APDamaged homes and debris are shown in the aftermath of Hurricane Ian in Fort Myers, FL.

As much of Florida takes stock Friday of apocalyptic damage - with searchers still checking for people in need and millions without power - deadly Hurricane Ian has begun lashing South Carolina, where an expected afternoon landfall threatens more lethal flooding and enough force to alter the coastal landscape.

With at least 21 deaths reported in Florida, Ian restrengthened to a Category 1 storm in the Atlantic and was barreling toward South Carolina with sustained core winds of 85 mph as of 8 a.m. ET Friday. Its center was due to move onto land between Charleston and Myrtle Beach, forecasters said, with winds up to 73 mph already hitting much of the Carolinas' coast and life-threatening storm surge and hurricane conditions expected within hours.

"This is a dangerous storm that will bring high winds and a lot of water," South Carolina Gov. Henry McMaster tweeted. "Be smart, make good decisions, check on your loved ones, and stay safe."

Meanwhile, Florida confronts the dizzying destruction Ian wrought through much of the peninsula Wednesday and Thursday after it smashed into the southwest coast as a Category 4 storm and plowed through central and northeastern areas. Homes on the coast were washed out to sea, buildings were smashed throughout the state, and floodwater ruined homes and businesses and trapped residents, even inland in places like the Orlando area.

Hundreds of rescues have taken place by land, air and sea, with residents stuck in homes or stranded on rooftops, and searchers have made many wellness checks, especially in the Fort Myers and Naples areas, where feet of storm surge inundated streets and homes.

And now, the storm's aftermath poses new, deadly dangers of its own. Some standing water is electrified, officials warned, while maneuvering through debris-strewn buildings and streets - many without working traffic signals - risks injury. Lack of air conditioning can lead to heat illness, and improper generator use can cause carbon monoxide poisoning.

In North Port between Fort Myers and Sarasota, Rosanna Walker stood Thursday in the flood-damaged home where she rode out the storm. Part of her drywall ceiling was hanging down.

"And all of a sudden, the water was coming in through the doors - the top, the bottom, the windows over here," she told CNN's John Berman. "It's all in my closets; I've got to empty out my closets."

"Everything got ruined."

At least 77 killed by Hurricane Ian

Authorities say the death toll from Hurricane Ian has risen to 77 people and that number is expected to grow as rescue crews make their way through the damage. NBC News' Liz McLaughlin has the latest on the recovery effort from Florida.

Death toll from Hurricane Ian surpasses 100 as the search for survivors continues in Florida

The number of people killed in Florida by Hurricane Ian rose to at least 101 on Monday, days after the storm made landfall at Category 4 strength, decimating coastal towns and leaving rescue crews searching for survivors while communities face the daunting task of rebuilding.

At least 54 people died in Lee County alone, Sheriff Carmine Marceno said Monday - up from the county's previously announced death toll of 42 - and officials there are facing questions about whether evacuation orders should have been issued earlier. Twenty-four deaths were recorded in Charlotte County - up from 12.

Hurricane Ian also contributed to the deaths of eight people in Collier County, five in Volusia County, three in Sarasota County, two in Manatee County and one each in Lake, Hardee, Hendry, Hillsborough and Polk counties, officials said. Four other people died in storm-related incidents as Ian churned into North Carolina.

More than 1,600 people have been rescued from Hurricane Ian's path in parts of southwest and central Florida since last week, Gov. Ron DeSantis' office said Sunday.

Now, as blue skies return, Floridians who took shelter while the hurricane raged have emerged - many of them still without power or clean drinking water - to find their communities unrecognizable.

More than 491,000 homes, businesses and other customers in Florida still did not have power as of Monday night, according to PowerOutage.us. In Fort Myers Beach, where search crews are going through the rubble one house at a time, power may not be restored for 30 days due its electrical infrastructure being destroyed, Lee County Manager Roger Desjarlais said.

The National Guard will be flying power crews to Sanibel and Pine islands to assess the damage and start working on restoring power, DeSantis said.

Many residents are without clean tap water, with well over 100 boil-water advisories in places around the state, according to Florida Health Department data.

• Hurricane Ian knocks out power to 2 million on destructive path across Florida - at least 77 dead (UPDATES)
• Hurricane Ian's damage to Florida fertilizer plant creates 'concern' about rising food prices
• Supply chain effects from Hurricane Ian could linger for weeks
• Hurricane Ian ranks 'top 5' to ever reach landfall in US, according to Gov. DeSantis
• Hurricane Ian heads toward Florida after slamming western Cuba as a Category 3 storm