National Weather Service officials are calling the rains in Texas a once in 500-year event.
In Houston, the conditions are horrible. The rain is falling nonstop, making the dangerous conditions even worse.
About 30 miles north of Houston, many cars can be seen submerged.
Although it's now a tropical storm, Harvey is still wreaking havoc and is very dangerous.
The problem is that it's moving very slowly, at times only three miles an hour, so the storm has dumped more than 20 inches of rain, and another 15 to 25 inches is expected through Thursday.
Crews are still out rescuing people Sunday night, thousands already in several communities along the Texas coast.
A portion of Interstate 45 is shut down. Of the six southbound lanes, at least three were covered in water in one area.
So, it's difficult for people to get around, many businesses in the area are shut down, as well as in other areas and it's going to be a very long night and difficult over the next few days.
It could take weeks for all the water to recede.
And of course, this devastation is not restricted to Houston.
About 30 miles to the Southeast in Dickinson, Texas there is similar damage.
Where there were once highways are now waterways for boats.
It would look like a river if not for the flashing traffic lights.
A county official says 800 to 1200 residents have been rescued in his county alone with 90 percent of those coming from Dickenson.