Katrina, et al.
Well, hurricane Katrina wasn’t nearly as bad as it could have been.
I think in the final analysis they will find it was the fact that the storm jogged north of the projected path, leaving the most severe part of the storm (The upper right hand quadrant) to the east of the city.
The radar also looked like the storm was in the middle of an eye wall replacement cycle when it came ashore. If indeed that was the case, it was a pretty amazing stroke of luck as the storm would have been even stronger the cycle completed prior to the hurricane force winds getting over land.
Considering how bad it would have been had the cycle completed earlier and the eastern eye wall made a direct hit, especially from a diagonal west-east jog, the Big Easy may have very well been completely destroyed.