Transcript for Greater Houston remains paralyzed as Harvey rages
lives and just behind me, you can see downtown Houston, and where the Buffalo bayou meets downtown, but there is so much water here. You can't tell where downtown ends and the bayou starts, and with all the help coming in from the federal and state governments and from California to Rhode Island, it's still not enough. Neighbors and strangers pitching in. For a third brutal day, rescues. You see right there, an armada of volunteers with boats. Th tens of thousands of people under evacuations. The rivers still rising and this dangerous development, two reservoirs threatening to spill. Tonight, there have been more than 4,000 high water rescues. More than 30,000 people are now expected in shelters, and 12,000 Texas National Guard members have been called up. That's every service member who is available to serve, and tonight, the storm is growing stronger again, threatening Louisiana as well, and it could be days before the sunshin shines here again. Reporter: Tonight, new evacuations, and fears that the death toll will rise across America's fourth largest city. There is a reality that we have to come to grips with. And that is that we are just beginning the process of responding to this storm. Reporter: What started with a direct impact on the tiny coastal town of rockport on Friday night has turned into a weather disaster affecting thousands of square miles and millions of people. More than 39 inches of rain already in spots, and more on the way. Officials releasing millions of gallons from the Addicks and barker reservoirs, hoping to prevent a catastrophic dam failure, but that water inundating neighborhoods, forcing thousands of residents from their homes. We had to leave some people behind which is really, really tough in these situations. They can't sit in these homes anymore with this water rising. Reporter: Thousands rescued by boat. More than 300 by helicopter. This is the water. Reporter: Iashia Nelson stranded with her children on her roof. There's water everywhere. We have nowhere to go. I have all my children, I lost everything. I have nothing but the clothes on my back. Please help us. I'm scared. Reporter: Hours later, finally rescued. To give you an idea of how paralyzed Houston is right now, look at this. The public transportation system is frozen. It stretches as far as you can see behind me, and all the way in front of us. Reporter: The Texas governor activating all 12,000 members of the National Guard. Emergency responder frequencies overwhelmed. There are two adolescent boys in kayaks that are missing that cannot swim. Reporter: Citizens are stepping in to help save each other. Under this overpass and around the corner. Along the highway, we met a driver who took us to a flooded out neighborhood where a woman was stuck in her home. The ceiling starting to buckle. Her family asking for help on social media. The house with the roof collapsed. Reporter: We saw the roof starting to cave in. The woman displaced by hurricane Katrina, now dealing with Harvey. I don't know. I have been through so much, so I really don't know. I'm a war veteran, so it's a bad joke for me right now. Reporter: But she refuses to go to the shelter. She doesn't want to leave her pets behind. In another part of Houston, the Bel Air section, people are working around the clock to save their neighbors. We told them about a woman we heard was trapped. They jumped into action taking us right to the home. Yvette! These are our neighbors, and one of our boys is here, and I'm going to start crying. Reporter: It's painful. They have to abandon a home they have lived in for 25 years with what they can carry. We are very fortunate. We're happy for the help and to get out. Reporter: And this woman thanking first responders to help her get to the hospital while she was in Laber. Writing, Landon jerred was born everything. Ly healthy. That mother telling us she never got the name of the people who saved her, but she will be grateful to them.
This transcript has been automatically generated and may not be 100% accurate.