A hurricane is a counter-clockwise low pressure circulation with strong winds (exceeding 64 knots, 73 mph), which develops over tropical oceans in summer and generally moves west and northwest. See Figure 2. Each year, starting in late spring and continuing into summer, the air becomes warmer and the oceans near the equator begin a warming trend. This change in temperature signals the beginning of hurricane season. At this time, warm air rises through the atmosphere and cools, causing condensation and forming clouds. The condensation releases latent heat and lowers the surface pressure. This may result in a circular storm, which sometimes develops into a hurricane (one type of tropical cyclone). In the Atlantic Ocean, the eastern Pacific Ocean, the Gulf of Mexico, and the Caribbean Sea, these tropical cyclones are known as "hurricanes." In the Far East, they are known as "typhoons," and in the Indian Ocean and off the north Australian coast they are known as "tropical cyclones" or "cyclones."

The hurricane is one mechanism by which nature releases the tremendous buildup of heat in the tropics. This heat, combined with tropical ocean moisture, is the hurricane's energy source. The fuel source for these storms comes from the evaporation of water from the warm seas. This vapor releases latent heat in the form of cumulus clouds. The dissipation of a hurricane once it moves inland from the open waters is often due to distance from the moisture that was supplied by the ocean. The hurricane serves as a transport mechanism of accumulated heat from warm tropics to the colder middle and higher latitudes. A hurricane causes the warm moist air to rise rapidly to high altitudes where it is eventually blown northward. This process is known as the "outflow" of a hurricane.