Why Do They Call Events Like This "Acts of God"

As I spend hours each day cleaning out my house from the recent flooding I have lots of time to think about things. I find myself wondering why in times of flooding disasters especially that we call these things "acts of God". I haven't been watching the news but I'm sure the Fred Phelps of the world are claiming, as they did after Katrina, that this is some kind of punishment from God for whatever imagined sins the particular nutjob believes that we have committed. That kind of thinking flies in the face of Genesis where God promised never again to destroy the earth with water. I rather think that localized destruction is probably covered under that promise as well. It seems to me more likely appropriate to call these things "Acts of Nature" rather than "Acts of God". Nature is like the rest of the Earth in that it is far from the perfect state it was created in.

Having watched as water rose and came into my house I've got a new respect for Nature's power. Even knowing we had a second floor to retreat to it was one of the most frightening things I have ever experienced. Yet we've seen tiny miracles throughout. God showing up and assuring me in ways that might only have made sense to me that He is not the author of this chaos and that He is with me as I deal with the aftermath. So do me a favor, don't insult me by calling this an act of God.