For our Non-Texan, Non-Houston friends-
To help you understand the devastation:
Houston is huge. The greater metropolitan area is circled by the Grand Parkway - which is 170 miles long. That makes the area of the circle inside the Grand Parkway over 2200 sq. miles.
2200 square miles of densely habited, urban and suburban, areas is flooded.
Imagine if the entire state of Delaware, with twice the population of Manhattan, was under water.
That's Houston.
It's still raining.