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. this is a line of city buses. it stretches as far as the eye can see behind me, and all the way in front of us. 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 along with a family of three that's stuck in high water. >> reporter: houston's own citizens are stepping in to help save each other. can you help us out? we're supposed to go under this overpass and around the corner. along the highway, we met a