Don't be so obtuse. 50 inches of rain ain't the point. Doesn't take anywhere near that much to flood areas that have been overbuilt. Suburbs all over Chicagoland were flooding earlier this year with about 14 inches of rain over a two day period. Happens more and more often and it ain't the size of the storm, it's the urban sprawl. Just makes it all the worse when a really big one hits.
I glanced through your comment too quickly earlier...was reading as other urban areas were able to handle this kind of thing. You're right, it doesn't take a biblical flood to cause a lot of problems with concrete and asphalt sprawl.
The other thing - for information because I gather that you must be a Brit or something- you cited an article that mentioned helicopters - and were apparently taken aback at the small number of "military" helicopters involved. Note that that article said 18 "Coast Guard" helicopters. In the U.S. the Coast Guard is not even part of the defense department/military. It is part of the Department of Homeland Security which includes customs, border protection, anti terrorism etc. So that figure does not include the massive, massive number of army, air force, navy, police department, fire department, county civil defense, national guard, and all the resources sent from a large number of other states. In addition, the helicopters are only part of the picture, most of it is being done the old fashion way by putting thousands and thousands of volunteer boats up every street and going door to door. So, that is just to say that Texas is a big state and yes 18 copters would not be many but it is much, much more than that. I am originally from a small town in Maine which is -what- 2500 or 3000 miles from Texas?, and yup, I just read that even one of the very small towns loaded up their rescue related people and went to Texas. Like dat. The state is sending a big crew and big load of supplies too but the little town just headed out on their own because the spirit moved them to do so.
Most countries build their roads with adequate drains both sides. The penny pinchers don't bother with that expense.
You are big on scouting for and rooting for more suffering for Americans. As a lib, you can spot deficiencies from the UK but would not actually be capable of doing any real work to help out in a difficult situation. The UK has had its share of flooding. Keep that in mind - especially since you are living in your mom's basement. Not a good combination.
"University of Washington atmospheric scientist Cliff Mass analyzed the available data to see just how big a role human emissions of greenhouse gases played in the storm. “And the results are clear: human-induced global warming played an inconsequential role in this disaster,” Mass wrote."