Category 5 storms are the most catastrophic hurricanes that can form, and occur only about once every three years on average in the Atlantic basin. Only four times — in the 1960, 1961, 2005 and 2007 hurricane seasons — have multiple Category 5 hurricanes formed. Only in 2005 have more than two Category 5 storms formed, and only in 2007 has more than one made landfall at Category 5 strength.