For the first time in history, the list used for naming tropical storms in the Atlantic Ocean is running out of names, DPA reported. With the naming of Tropical Storm Wilma Monday morning, the list of 21 names used this year has reached its end. Wilma is gathering strength and is expected to become a hurricane this week, and could head toward the U.S. Gulf Coast or Mexico by next week. This means that the Greek alphabet will now have to be used if there is another tropical storm, which would be called "Alpha". There are six more weeks until the hurricane season ends November 30, and it is likely that there will be at least one other named storm. The 2005 season has already been one of the most active in history and has featured some of the fiercest and deadliest storms ever to hit the region. Hurricane Katrina hit August 29 and killed about 1,300 in the U.S., with a final death toll still pending. It has become the most expensive storm in U.S. history and crippled parts of the U.S. Gulf Coast. Hurricane Rita hit the area again September 24 but caused much less damage. However, the storm again disrupted U.S. oil production and refining capabilities. Hurricane Stan made landfall in Mexico October 4. While not as intense as Katrina and Rita, the storm caused massive rainfall resulting in floods and mud slides that have left hundreds dead. There is no final death toll yet, but officials fear that hundreds more will be discovered in coming weeks. With these deadly storms hitting the region, it is probable that at least two hurricane names will be retired. There are six lists of names that are used in rotation, which means the 2005 names will again be used in 2011. The National Hurricane Center has put together lists of hurricane names since 1953. They are now maintained and updated by a committee of the World Meteorological Organization (WMO). While only women's names were used in the past, male and female names have alternated since 1979. But Katrina and Stan will likely not be on that list. Names are retired if the storms bearing them were especially deadly or costly and it would be insensitive to use them again. The WMO committee will convene and determine which names should be stricken and then find replacements. --SP 2200 Local Time 1900 GMT