Just the fact that a major American city had to be evacuated, there's no precedent for that -- not just in American history, but world history.
Levees are a double-edged sword; they give people a false sense of security.
Anybody looking at the evidence could see this coming.
The point that has to be made is that national disasters are, in the aggregate, predictable, and we can budget for them, ... Acts of God: The Unnatural History of Natural Disasters in America.