Hurricanes, or their equivalents, occur in other parts of the world. In the western North Pacific Ocean, for example, they are known as typhoons. A hurricane's life cycle may pass through four distinct stages, tropical disturbance, tropical depression, tropical storm and finally, a hurricane. All are classified as tropical cyclones. A tropical disturbance is a discrete system of clouds, showers, and thunderstorms that originate in the tropics and maintains its identity for twenty-four hours or more.
Tropical waves are a type of tropical disturbance.
They are troughs of low pressure that move generally from east to west, imbedded in the tropical easterlies. They are also called easterly waves. Tropical Storm A system is given a name by the National Hurricane Center once it reaches tropical storm status. The term hurricane is derived from the Spanish word, huracan. In turn, the word huracan probably came from Hunraken, the Mayan storm god, or Hurakan, the Quiche god of thunder and lightning, or any of a number of other Caribbean Indian terms for evil spirits or big winds.