Tech Insider put together this excellent educational clip – as Hurricane Irma bears down on the East coast – explaining how and where hurricanes (aka tropical cyclones) form, and why they often follow a similar course.

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In fact, Irma, Harvey, and Jose were all born on the other side of the Atlantic, off the coast of Africa, and the Sahara desert may be to blame.

In short: Tropical cyclones typically form over large bodies of relatively warm water. They derive their energy through the evaporation of water from the ocean surface, which ultimately recondenses into clouds and rain when moist air rises and cools to saturation. The strong rotating winds of a tropical cyclone are a result of the conservation of angular momentum imparted by the Earth’s rotation as air flows inwards toward the axis of rotation, known as the Coriolis force.