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

A caravan of utility trucks is making its way from several states toward the parts of Florida most battered by Hurricane Ian to restore power after the worst of the storm has passed, Florida Gov. Ron DeSantis announced during a news conference Wednesday afternoon.

"We have a massive, massive mobilization," DeSantis said, adding that workers are coming from other southern states accustomed to hurricane cleanup, such as Texas and Louisiana.

More nearly 1.5 million customers in Florida were without power Wednesday as Ian made landfall near Fort Myers.

Ian continued to batter a large swath of Florida at 6:15 p.m. ET, with life-threatening storm surge all along the southwest coast — up to 12 feet in some places, DeSantis said.

Downtown Naples was reportedly completely flooded due to record storm surge, and while there were also reports of structural damage in Lee County, DeSantis said.

"This was a top five hurricane to ever hit the Florida peninsula," the governor said.

DeSantis said that devastating inland flooding was inundating much of the regions experiencing hurricane conditions, as well.

DeSantis has declared a major disaster in the state.

-ABC News' Will Gretsky