Aside from the fact that many urban areas have reached the point where you build where you can and hope for the best, these graphics from the National Weather Service, besides showing how Hurricane Harvey has forced them to revise the "amount of rain" color coding of their graphics, also show the sheer extent of the storm.
San Antonio is hardly "the beach."
#Harvey in perspective. So much rain has fallen, we've had to update the color charts on our graphics in order to effectively map it. pic.twitter.com/Su7x2K1uuz— NWS (@NWS) August 28, 2017