Super Power hiding inside Super Dome

It was pathetic to watch the American super power to hide inside a super dome. Hurricane Katrina is being labeled as the worst natural disaster ever to hit USA, it has destroyed one of the the biggest cities in southern USA. Was it so devastating? Did no other countries face such a crisis, when the hurricane came about people fled the city, is it the same situation in other countries too? Are the other nations also having super domes? I wonder how USA was so unprepared for it although knowing that New Orleans was below sea level why did it allow humans to live in that place.

One thing I never understood why these people construct their houses with wood, when it is safe to make concrete houses. If the houses were concrete atleast half of the houses could have ben saved. Now people dont have homes to stay, where would they go now? I understand if there are wooden houses in the north but why in south?