Less is known about these storms that we would like but we do have a rough idea. Hurricanes form in tropical regions where there is warm water (at least 80 degrees Fahrenheit / 27 degrees Celsius), moist air, and converging equatorial winds. Most Atlantic hurricanes begin off the west coast of Africa, starting as thunderstorms that move out over the warm, tropical ocean waters.
If the water is warm enough, the wind is converging, and the pressure from high altitude and low differs greatly, a hurricane can form. The warm air near the water will pick the water up and turn into clouds, the high pressure from above will then be forced down to the surface (due to the pressure differences) and it will warm and collect water. This cycle continues and the storm gets bigger. The reason a storm will die when it hits land is that it loses its source of water.
Factors such as global warming will increase the frequency and intensity of hurricanes. As the water warms it becomes easier for the hurricane to lift and use in its clouds, the warmer the water the bigger the storm. To fully understand a hurricane we'll need to look into the water cycle and pressure systems.
