Lee Health, the Florida-based health care system, has evacuated patients out of three of its four hospitals because they don't have running water due to Hurricane Ian, Dr. Larry Antonucci, president and CEO, said in a video statement Thursday.

“At the present time, our structures and facilities are in good shape. They’ve weathered the storm well, but our infrastructure is challenged in the way of our water supply and power,” Antonucci said.

Lee Health is working with the Agency for Health Care Administration in Florida and local emergency management to arrange for the evacuations of patients to other hospitals outside of Lee County, which includes Fort Myers.

-ABC News' Alexandra Faul

Disney World, which was shut down Wednesday and Thursday, will begin a phased reopening on Friday, according to the resort.

The theme parks and Disney Springs will begin reopening "as we assess the impact of Hurricane Ian on our property," Disney tweeted.

The exact opening hours will be released later Thursday, Disney said.

More than a foot of rain has already fallen in the Orlando area with some light rain still ongoing. Hundreds of people have been rescued from flooding in the city.

Ian is expected to be at least a Category 1 hurricane with 75 mph winds when it makes its third landfall near or north of Charleston, South Carolina, Friday, in the late morning or early afternoon.

Ian, currently a high-end tropical storm with winds up to 70 mph, is moving off the east-central coast of Florida, currently 40 miles northeast of Cape Canaveral. The storm is forecast to regain hurricane strength in the next 12 hours.

Hurricane warnings remain in effect for the entire coast of South Carolina. Charleston already had almost 2 foot storm surge Thursday as Ian gets closer, and storm surge is forecast up to 7 feet.

The storm surge combined with up to 10 to 12 inches of rain is extremely concerning as the area floods easily.

-ABC News' Melissa Griffin

President Joe Biden said officials are hearing early reports of what may be a substantial loss of life due to Hurricane Ian, he said at a press conference at Federal Emergency Management Agency headquarters Thursday.

"This could be the deadliest storm in Florida history. The numbers we have are still unclear, but we're hearing early reports of what may be substantial loss of life," Biden said.

Biden also promised support to state and local officials as officials assess the damage caused by the storm, saying the federal government will cover the entire cost of clearing debris and of rebuilding public buildings like schools and state fire stations. The government will also be providing support to people with destroyed or damaged homes.

Federal Emergency Management Agency Administrator Deanne Criswell warned Tuesday, "Floridians are going to experience the impacts from the storm for a very long time."

"Our biggest concern as we wait for this storm to make landfall is storm surge," Criswell said. "In 2018, when Hurricane Michael impacted the Florida Panhandle, there were five recorded fatalities as a result of storm surge. So therefore, if people are told to evacuate by their local officials, please listen to them. The decision you choose to make may mean the difference between life and death."

President Joe Biden on Tuesday urged residents to "evacuate when ordered."

Biden said he spoke to the mayors of Tampa, St. Petersburg and Clearwater Tuesday morning and told them to "contact me directly" for "whatever they need."

Criswell said a search and rescue coordination group has been activated, including members from FEMA's urban search and rescue teams, the Coast Guard, the Department of Defense and the Department of the Interior.

The Red Cross has established 29 shelters and is prepared to open 60 more shelters if needed, she said.

Criswell stressed, "To those who may be watching at home, get ready and do not underestimate the potential that the storm can bring."