Warm water is fuel for hurricanes, and Irma was moving over water that was 1.8 degrees (1 degree Celsius) warmer than normal. Four other storms have had winds as strong in the overall Atlantic region, but they were in the Caribbean Sea or the Gulf of Mexico, which usually have warmer waters. Hurricane Allen hit 190 mph in 1980, while 2005's Wilma, 1988's Gilbert and a 1935 great Florida Keys storm all had 185 mph winds.