South Carolina Gov. Henry McMaster said conditions are "very dangerous" as Ian comes ashore, but so far the amount of water in places like the hospital district of Charleston is lower than expected.

"But I would ask people: Don't quit yet because this is still coming. We're not out of the woods," McMaster said.

South Carolina has positioned 90 National Guardsmen for high-water vehicle support. They have received a few requests for support, including for swift water rescue teams, said Kim Stenson, the head of South Carolina Emergency Management.

Stenson said they expect calls for damage and flooding to increase throughout the day.

A tornado threat is increasing as Hurricane Ian gets closer to the coast of the Carolinas.

Myrtle Beach and Greenville, South Carolina; Wilmington, North Carolina and Virginia Beach, Virginia, are all under tornado watch through 10 p.m.

A tornado warning is also in effect south of Wilmington.

-ABC News' Melissa Griffin

President Joe Biden pledged the U.S. would do "whatever it takes," to help Florida recover from Hurricane Ian, stressing the effort would be done as "one nation and one America," during an event at the White House marking the Jewish New Year.

"We're working very closely with the governor and the entire Florida delegation, Democrat and Republican, making sure that we can do everything we can, including now search and rescue, recovery and rebuilding efforts, but it’s going to go on for a long while. And whatever it takes, we’re going to be there, as one nation, and one America. We're not going to walk away," Biden said.

Biden noted the time of celebration is also a "very difficult time for so many Jewish families in Florida," and those with loved ones in the state.

"[O]ur heart goes out to everyone there in the state experiencing what could be maybe one of the most devastating hurricanes in the history of that state," Biden said.

-ABC News' Molly Nagle

President Joe Biden spoke with South Carolina Gov. Henry McMaster Friday ahead of Hurricane Ian's expected landfall.

Biden told McMaster the administration will provide whatever assistance South Carolina needs. Biden issued an emergency declaration for South Carolina Thursday night.

-ABC News' Molly Nagle

President Joe Biden spoke from the White House Friday afternoon about Hurricane Ian's wrath, describing the devastation in Florida as well as warning residents of South Carolina to be prepared for another landfall.

"We're just beginning to see the scale of that destruction," Biden said of the damage in Florida. "It is likely to rank among the worst in the nation's history. You have all seen on television, homes and property wiped out. It is going to take months, years to rebuild."

He added, "I just want the people of Florida to know we see what you are going through and we are with you. And we are going to do everything we can for you."

Biden said the U.S. Coast Guard has mobilized 16 helicopters, 18 rescue boats and six fixed-wing planes to help in search and rescue in Florida. More than 100 people have been rescued by the Coast Guard, Biden said. Hundreds more have been rescued by volunteers.

"The federal government will cover every cost, 100% of the cost, to clear the massive debris left in the wake of the hurricane and these counties," the president said. "It all needs to be cleared out for communities to begin the hard work of trying to get back on their feet."