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

Ian remains a tropical storm with winds of 50 mph, but the storm system is expected to rapidly intensify on Sunday as it moves over warm waters in the Caribbean Sea, according to the National Hurricane Center.

The seawater currently carries very favorable conditions for strengthening over the coming days, with temperatures between 85 and 90 degrees Fahrenheit -- the perfect temperatures for fueling a powerful storm as it stays over open water.

Ian is expected to strengthen to a hurricane by Sunday night and into a major hurricane later Monday night as it passes by Cuba.

The NHC currently forecasts Ian to strengthen into a major Category 4 hurricane on Tuesday in the Gulf of Mexico as it heads toward Florida.

Ian is expected to make landfall on the west coast or the panhandle of Florida on Wednesday or Thursday.

Some weakening could occur before the storm system makes landfall, possibly dipping below major hurricane status before impacting coastal communities.

A hurricane warning is currently in effect for the western portion of Cuba, where flooding rains and major storm surge are forecast.

-ABC News' Riley Winch