"Fatalities are in the hundreds," Lee County Sheriff Carmine Marceno told Good Morning America on Thursday.

Ian was moving northeast across Florida at about 8 mph with maximum sustained winds of 65 mph at 5 a.m. Thursday, according to the National Hurricane Center. However, the agency warned that Ian could pick back up and reach hurricane strength as it reaches Florida's east coast on Saturday, posing risks to Georgia and the Carolinas.

The NHC downgraded Hurricane Ian to tropical storm status early Thursday morning after the storm began to weaken gradually overnight Wednesday as it moved across central Florida.