Transcript for Millions bracing for ‘unsurvivable storm surge’ from Category 4 hurricane
Good evening and it's great to have you with us here on a very heavy news night. We begin tonight with that category 4 hurricane now bearing down on the U.S., expected to make landfall within hours. Hurricane Laura speeding toward the gulf coast. Texas and Louisiana. Emergency evacuations. Authorities warning time is running out. We've been watching here as this hurricane grows in strength, now upgraded to a cat 4, winds 145 miles per hour. And one of the real concerns here, it is going to hit right in the middle of the night. And just look at the size and scope of this hurricane. These images from the international space station. It is 400 miles across. The center of the storm still over the warm waters of the gulf, which, as you know, fuel this. The effects already being felt tonight. More than a half million people under mandatory evacuations. Some in shelters in lake Charles, Louisiana, there. Military aircraft being flown to safer ground out of Barksdale air force base. The outer bands of the storm making their mark already. This is from Lake Charles and all of this hidden in the middle of a pandemic, as well. Thousands of coronavirus cases just in the region expected to get slammed by this storm. So, we'll carefully guide you through it all tonight. Ginger zee is live in port Arthur, Texas, tonight, with the latest track and guidance for us. What do you expect? Reporter: David, the words unsurvivable storm surge were used by the national hurricane center from my point here in Port Arthur, east through southwestern Louisiana. This all comes just a couple of days before the 15th anniversary of hurricane Katrina, which obviously hit farther east from here and into Mississippi, but that was a cat 3. This is going to be a cat 4. The only cat 4 potentially in history to hit this part of southwestern Louisiana. Now, I want to take you into what we are looking at, right? So, this is the lake behind me. The hurricane is about 120 miles to the southeast. This is a very shallow deck that leads up to all of these homes right here along the gulf. 10 to 20 feet, that's going to overtake these homes. And that's why a satellite image like the one you see here is really frightening. We are just hours from the winds starts to pick up in intensity. After midnight, we should see land. . When we talk about wind gusts, 50, you say, okay, then you go to 105 here in Port Arthur, look at Lake Charles at 4:00 A.M., 127 miles an hour, even through 7:00 A.M. You have three hours of 120 to 130-mile-per-hour gusts, you are going to have ridiculous damage. That 10 to 20-foot surge could go 30 miles inland, so, lake Charles, Cameron, Louisiana, we anticipate significant problems here. And this is going to all be wrapping up and moving and not going to move that -- it's going to move quick enough, but gosh, it's going to do a lot of damage, all the way Shreveport. I anticipate power outages all the way up into Arkansas. David? All right, ginger, you and the team, please be safe into the evening hours. And we took note of what ginger just said there. This is now a category 4 hurricane. Hurricane Katrina was a cat 3. We all remember the devastation. I remember reporting right in the middle of it as it was so tonight, across Louisiana, New Orleans, points west of there they're all taking this very seriously. Meteorologist rob Marciano on that part of the story tonight. Reporter: Tonight, the time to evacuate is over. Laura's coming ashore, packing 140-mile-per-hour winds and what the national hurricane center is calling unsurvivable storm surge. Here come the first bands of hurricane Laura. It's only going to get worse. Hurricane hunters flying into Laura's eye today. The storm now more than 400 miles across. The surge from this storm is going to push water for miles inland, at a height of 10 to 15 feet. That's water easily up and over my head. That's up and over this roofline. The surge will be even higher than that near the coast. And it's coming in the middle of the night. We met Freddie rosteet who has to ride out the storm at this Lake Charles blood bank. We're hoping that this wall does what it was made for. Reporter: So that he can supply hospitals with needed blood. I've been doing it for 30 years and that's what I'm Reporter: Louisiana's governor activating the entire National Guard. Trucks that can be used for high water rescues staging north of New Orleans. And if you think you're safe because you made it through Rita in southwest Louisiana, under understand this storm is going to be more powerful. Reporter: The military evacuating aircraft from Barksdale air force base. This is home to 55% of the nation's tra steejic oil reserves. Most of its jet fuel and also some of the biggest refineries in the country. Reporter: Back in lake Charles, the mayor tells me he's worried too many have decided to ride it out. I'm going to be honest, I am concerned that we didn't have the evacuation numbers that we probably should have. So, let's get right to rob Marciano, live from Lake Charles tonight, and rob, I know it's the surmg and the winds. What are you expecting where you are? Reporter: We could see winds over 100 miles an hour, David. And we don't usually say that with any sort of confidence, but this storm is an absolute beast. Extremely dangerous. It's going to cut across Louisiana like a giant tornado. Not to mention the storm surge that could be catastrophic. It's just going to be devastating here across southwest Louisiana and lake Charles and life will be flat-out different here after tomorrow. David? All right, rob, thank you.
This transcript has been automatically generated and may not be 100% accurate.