FrankSpace

Katrina was downgraded from Cat 5 to 4 before it hit land, it also changed course by 50 miles to the north. As a result the highest winds to hit N.O. were 100mph, so efectively only a high Category 2 storm hit N.O. The levees were supposed to be able to take a Cat 3 storm, but funding for improvements and maintainence were cut drasticly from 2001 onward by the Bush administration. Maybe they would have failed anyway, but that doesn't look like the way to bet.