Transcript for Rising waters inundate whole section of Houston
Thanks for joining us on this special edition of "World news tonight" this Sunday. I'm Tom llamas. Tonight, the disaster in Texas is deepening. Houston is a city in crisis. And now, a city of islands. The flood waters isolating sections like you see behind me. As the National Guard rolls in, the water has cut off sections of the interstate that wraps around Houston. This big rig stood no chance in the rising waters. And we spoke to the drive who had to be rescued. We'll have more on that in a moment. But first, let's get you caught up. Overnight, more than four inches of rain an hour coming down. Million waking up to a scene of epic flooding. And tens of thousands calling for help, needing rescg rescue. The 911 system overwhelmed. Neighbors and strangers stepping in to help. The disaster here is staggering by every measure. More than 2,500 rescues, 3,000 state and national guards activated. Forecasters now predicting some areas could get 50 inches of rain. The national weather service already calling the storm unprecedented and beyond anything experienced. And here in Houston, we are heading into another night of torrential rainfall. Tonight, with the water still rising and people still trapped, Houston, one of America's largest cities, is crying out for help. Issuing a nationwide sos. The current was getting high. We had to bust a window to get out. Reporter: Officials begging residents to stay strong. I know what you're going through. I know you're scared. I know you're panicked. I know you feel, like, in a desperation right now. But know that help is coming, help will be there, and we will help bring all of this back after this is over. Reporter: The national weather service now predicting some areas to get 50-plus inches of rain. And saying in no uncertain terms, quote, "This event is unprecedented and all impacts are unknown and beyond anything experienced." High water teams pulling hundreds of people from their vehicles on inundated roads. We're on the 610 loop and there's a rescue happening. A truck driver stuck in the flood. Two good samaritans pulling out this truck driver, rosemary Montgomery from California. She told me there were no signs, telling her to stop. The truck, stuck into the water, no longer able to move. The water entering her cabin. The water came up all the way to your side. She calls those two men her heroes. I said, stay calm, I'm coming to get you. Reporter: With resources stretched thin, emergency management officials asking the public for help, saying they need more boats. Other desperatresidents plucked from rooftops. Some by coast guard helicopters. Choppers from as far away as San Diego and cape cod now joining the effort. That person is on their roof. They've been yelling help and hello for the last few minutes. Reporter: Thousands more trapped inside their homes. Amid rising water. Houston's 911 call center, overwhelmed. Oh, yeah. Got you. The water came up so fast. It was incredible, the amount of water. Reporter: Residents going door to door to check on their neighbors, helping them and their pets get out. Oh, okay. Reporter: Producer Joe Gleason from our station KTRK, broadcasting live as the water inside his home continues to rise. When it started coming in it was just, you know, a couple puddles here. And then it got to be more and then more and then we just said, "You know what, let's just get safe." Reporter: Checking in at 1:30 -- I'd like to just get out of here because I'm afraid of how high this is going to get tonight. We had to actually climb to the attic to the house and I had my tools and if it kept rising I was going to bust the roof open. Reporter: Officials warning residents to stay out of their attics. We would ask that you mark your roof to be seen from the air, wave sheets, towels, or anything to get our attention. We would ask that you don't go into your attic. Rescuers from the air cannot see you. Reporter: With bayous and rivers overrun, that contaminated water, a potential toxic soup containing oil, gasoline or raw sewage. Another danger in the sky, the threat of tornadoes. The images and rescues, so heart-wrenching to see. And the president saying he praises all the agencies working together, and he's expected to visit Texas on Tuesday.
This transcript has been automatically generated and may not be 100% accurate.