Hurricanes, typhoons and cyclones begin as atmospheric disturbances, external – such as, for example, a tropical wave, an area of low pressure where thunderstorms and clouds develop.
As warm, moist air rises from the ocean surface, winds in the storm cloud begin to spin. The process is linked to how the Earth’s rotation affects winds in tropical regions just away from the equator.
For a hurricane to develop and keep spinning, the sea surface generally needs to be at least 27C to provide enough energy, and the winds need to not vary much with height.
If all these factors come together, an intense hurricane can form, although the exact causes of individual storms are complex.