Hurricane Katrina has been the most expensive natural disaster in the U.S. history. You may think that this should mean that it was at least the strongest hurricane of 2005.
However, then you may realize that hurricane Rita was actually stronger. So you would change your mind and argue that Katrina was the second strongest hurricane of the year.
Nevertheless, you would still be wrong. Actually, hurricane Wilma has just become the strongest hurricane of 2005 and the strongest hurricane on record, with pressure dropping as low as 882 mbar (rank 1) near the center, compared with Rita's 897 mbar (rank 4) and Katrina's 902 mbar (rank 6).
What does it mean? First of all, it means that the particular year 2005 and the particular ocean called the "Atlantic ocean" has seen very many strong tropical cyclones compared to other years and other oceans. Note that the tropical cyclones are called "typhoons" in the East Asian region, and they have other names in other parts of the world.
These other regions have seen no increased statistics of the tropical cyclones. "Hurricanes" with this particular name are a local effect. Wilma is not the strongest tropical cyclone every: it is the 10th strongest tropical cyclone ever. There have been 9 stronger typhoons, so please don't think that we live in an globally exceptional historical era. ;-)
Hurricanes prove feminists wrong
Second of all, it proves that the feminists have been completely wrong once again. ;-) By the 1970s, only female names were used for the hurricanes. (This was based on a comparison of winds and women: when they arrive, they are warm and pleasant summer winds; when they leave, they take cars and houses away with them.) The feminists conjectured that it was a kind of discrimination and men may be equally destructive if they are employed as winds. :-)
Consequently, male and female names have alternated. But something that the feminists don't realize is that you can't simply hide reality. Katrina, Rita, and Wilma are all female. The male hurricanes in between were jokes or they did not become hurricanes at all. Andrew 1992 is the only proud representative of the males in the field. The hurricanes after Wilma will be called Alpha, Beta, Gamma, Delta, which - I believe - are also female, at least in Czech. ;-)
More seriously, does the increased frequency of hurricanes mean something? An explanation would have to explain why it is exactly 2005 and the Atlantic ocean in which the tropical cyclones became frequent. Even the official spokesmen of the alarmists agree that you can't deduce anything about "global warming" from a few hurricanes. I personally can't imagine that there is a good explanation why it is exactly 2005 and the Atlantic ocean.
Why did we get three gigantic hurricanes exactly half a year after the Kyoto protocol became valid? Will the Kyoto protocol increase the frequency of hurricanes even further? Why did we get three gigantic hurricanes in the same year in which the feminists attempted to humiliate president Summers? Do you really believe that there will be an explanation like that?
There could exist a mechanism that "squeezes" the hurricanes into the same year more often than the Poisson distribution would lead you to believe. But I actually don't think that the data support the conjecture that the available statistics deviate from the Poisson distribution in a significant way. There is no effect and therefore one should look for no explanation unless he is superstitious. As far as we can say today, the increased frequency of hurricanes in 2005 is a coincidence.