I did some walking yesterday and came upon the scene above. (You may have to click on it to make it engorge itself.)
Many years ago, when I lived in Tucson, I was told that the most common form of death in the desert was drowning. Seems paradoxical but if you live in the desert for a while you understand it. One doesn't usually associate the desert with super-saturated wetness, but flash floods can be very convincing. The country is full of dry washes, as in the accompanying picture, and when the run-off from the hills and high places from a sudden storm comes down the washes they are not good places to be.
Most dry washes, unlike the one shown (looks like a road but isn't), are dug in a bit, with high sides. I have seen sides ("banks" if you will) that are six inches high and I have seen them ten feet high. The higher ones seem out of place until you have seen a wall of water six or eight feet high rushing down from a high-country storm.