Five-thousand members of the Florida National Guard have been activated to help during Hurricane Ian. Another 2,000 guardsmen from Tennessee, Georgia and North Carolina are also coming to help, Florida Gov. Ron DeSantis said.

Nearly 300 ambulances and support vehicles are being deployed to areas bracing for Ian’s landfall, DeSantis said.

-ABC News’ Alex Faul

In Tampa, where residents are bracing for 10 feet of dangerous storm surge, the Tampa International Airport may shut down parts of its airfield and facilities over the next day or two, airport officials announced.

The airport is in an evacuation zone, but because it’s critical infrastructure, it’s “exempt from the storm evacuation order and will stay open until a closure is necessary,” airport officials said in a statement.

It’s been 101 years since Tampa last had a direct hit from a major hurricane.

Hillsborough County Public Schools in Tampa will be closed Monday through Thursday due to the storm. Instead, some schools will operate as storm shelters, the district said.

In Sarasota County, schools will be closed on Tuesday.

NASA said it will roll the Artemis I rocket off the launch pad and back to the vehicle assembly building on Monday night due to the storm.

“Managers met Monday morning and made the decision based on the latest weather predictions associated with Hurricane Ian, after additional data gathered overnight did not show improving expected conditions for the Kennedy Space Center area,” NASA said in a statement. “The decision allows time for employees to address the needs of their families and protect the integrated rocket and spacecraft system.”

Lee County Sheriff Carmine Marceno told ABC News' "Good Morning America" that Hurricane Ian was very unpredictable, with officials tracking the storm every minute and they didn't know where it would hit.

"This is a life-changing event for all of us. We tracked that storm up the coast of Florida, it was very unpredictable," Marceno said.

He added, "We didn't know where it would hit. I can tell you it came into Lee County strong and it was slow moving."

Marceno said there were fatalities, but he didn't yet know the exact number.

Marceno said they are already assessing the area, but the whole area is "crushed" and people are trapped. Marceno said they have thousands of 911 calls that they are currently answering.

"We still cannot access many of the people that are in need," Marceno said. "It's a real, real rough road ahead."

In Volusia County, on Florida's east coast, authorities said one person has been confirmed dead. A 72-year-old man who went outside to drain his pool was swept away and found dead in a canal behind the house.