I understand that the infrastructure could lead to a different type of situation than what is common--even compared to what happened in New Orleans.
the worst hurricane to hit NC was Floyd in 1999. It was our worst natural disaster, with damages totaling ~$5billion.
like Katrina, the problem was the storm surge. Just about all of eastern NC, about 100 miles or so in from the coast was flooded. Now, there isn't a whole lot of stuff going on in eastern NC--mostly pig and tobacco farms (these is where we get those famous images of the pigs huddled on top of the barn surrounded by flood waters). It shut down that part of the state for a few months, and devastated the hog industry--which was #2 in the country, I believe. There were some 50 deaths, maybe?
Now...imagine that same sort of thing in Manhattan...it would be many, many more magnitudes more horrible.
The reality, though, is that the conditions up north tend to make this type of storm, hitting at that spot on the coast with that power essentially impossible. Floyd had followed after Dennis?, which had already inundated the area with water. same with Katrina--there was the one shorty after that took out another levy, I think, and I could be wrong but another preceded Katrina?
Those type of situations just aren't going to occur in the north east. But if one manages to climb along the coast and stay out to see, then turn in, magically, it would easily be the worst natural disaster that we have seen in this country.