When two hurricanes come close enough to each other and begin to interact, this phenomenon is called the Fujiwhara Effect. It involves the two storms rotating around a common center in a kind of "dance." Depending on their size, intensity, and distance, the interaction can result in several outcomes: the storms may orbit each other and then separate, one storm may absorb the other, or in rare instances, they can merge into a single larger storm. This effect typically happens when the storms are within about 870 to 900 miles of each other. The Fujiwhara Effect is named after Japanese meteorologist Sakuhei Fujiwhara, who first described it in 1921.