Transcript for Authorities issue final warning as millions ordered to evacuate

This is why authorities tonight are saying remain vigilant when it comes to the track of this hurricane. A slight change could spell real trouble here at home. Tonight, more than 2 million Americans are under mandatory evacuations from Florida all the way up to North Carolina. This is from South Carolina late today, all lanes of interstate 26 right there actually heading in the same direction, away from the shore. Thousands of flights canceled up and down the coast. Operations halted at 11 Florida airports. The Orlando airport, the main one there, shuts down tomorrow. ABC's gio Benitez is in new smyrna beach tonight. Reporter: Tonight, with more than 2 million people ordered to evacuate, from Florida all the way to North Carolina's outer banks, the message from authorities is clear -- If you're in a mandatory, you have -- you just have to get out. Reporter: Dorian now menacing the Florida coast just over 100 miles offshore. Some still boarding up. We met Lenny glover also we headed further inland. So right now, you're just kind of watching and waiting. Like everyone else in volusia county. Reporter: But tonight, so many have already left their homes and businesses behind. We've now made it more inland but just take a look. Even here, business after business is just boarded up. People are listening to those warnings. It's a ghost town here. Mandatory evacuation is now in place. Please collect your belongings, vacate and seek shelter. Reporter: In Boynton beach, police going door-to-door. Patients at hospitals and dozens of nursing homes are being moved inland. In South Carolina, all lanes of this highway are now leading away from the coast. Tonight, many in Charleston are still filling sand bags. Our Steve osunsami is there. People are deciding to stay in many instances and are getting sandbags at locations Reporter: And tonight, about 8,000 troops standing by up and down the coast, emergency vehicles in position. Let's get to gio, live from new smyrna beach, Florida. And you were telling us a short time ago, there are still people who are evacuating tonight? Reporter: Oh, absolutely, David. A lot of people are watching and waiting to see what this storm does. But it's not too late to leave. So, if you do decide to evacuate, make sure you're taking your medications with you and, of course, some important documents just in case. David? But I'm glad to hear people are heeding the call. Gio, thank you.

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