Some models of the effect of climate change on hurricanes predict fewer storms but stronger storms. While all storms are a threat to the Louisiana coast, it is the large storms that threaten the very existence of cities such as New Orleans. Dr. Jeff Masters’ WunderBlog has excellent discussion of these models and whether the 2010 season is consistent with this theory:
http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1776