Amtrak and various airlines are preparing as Hurricane Florence churns on a projected path toward the Carolinas.

The Category 4 hurricane is expected to make landfall late Thursday or early Friday and cause potentially disastrous flooding in parts of Virginia as well as North and South Carolina. States of emergency have been declared in the three states as well as Maryland, with more than one million residents ordered to leave the areas.

Amtrak trains in the South are undergoing cancellations or schedule modifications beginning Wednesday and lasting through Sunday. Amtrak will waive additional charges for those looking to change their reservation due to inconveniences caused by Hurricane Florence.

The changes affect routes along the coastal corridor. Northeast Corridor trains won't operate south of Washington, while trains on some other routes that run through Philadelphia en route to or from the South are canceled entirely. A full list of impacted trains can be found on Amtrak's website.

In an update Tuesday, Philadelphia International Airport reminded passengers with plans to fly to or around the potentially storm-impacted areas to check in with their airlines.

"Many airlines are offering fee waivers to change travel plans to/from certain cities during certain dates," the airport wrote on Twitter.

American Airlines, United Airlines, Southwest, and Delta have posted waiver or rebooking and rescheduling information on their websites ahead of Hurricane Florence's expected landfall.

Sara Orsi, a spokeswoman for FlightAware, told USA Today "It's really difficult to speculate this far out, since there's still significant uncertainty in the track," but travelers could see cancellations beginning Wednesday.

"Based on current models, it's likely that the biggest impact will be to the Charlotte airport, which is an American Airlines hub," she said. "If the storm turns north towards D.C., more airlines will be impacted."