Hurricanes are some of the most powerful and violent weather events on the planet. In this year alone, an estimated 154 (at least) people have lost their lives, and different communities hit hard by these storms have accumulated over hundreds of billions of dollars in damage. Therefore, since these storms have such tremendous impact on our lives, let's learn more about them. More specifically, how do they start and how are hurricanes different from other storms like typhoons or cyclones?
First of all, hurricanes, typhoons and cyclones are the same storm, but we use these different terms to refer to where they occur in the world. Typhoons only occur in the Northwest Pacific while cyclones occur in the South Pacific and Indian Ocean. Storms that form over the Atlantic Ocean or eastern Pacific Ocean are known as hurricanes. Furthermore, the proper scientific term for all these weather events is tropical cyclones.
So how do tropical cyclones develop? Well, they all form the same way by starting over warm waters (near the equator) that are at least 80 degrees F for at least the top 50 meters below the surface. The warmth of the water heats the air above the surface, causing it to rise and leaving an area of lower air pressure below. As a result, air from surrounding higher air pressure areas rushes in to replace the lower air pressure area, becomes warm itself, and rises. Also, as warm, moist air rises, it condenses to form clouds. Therefore, a system of thunderclouds and winds form and is continually fed by the evaporation of warm ocean waters, causing the storm to rotate faster and faster. If the storm is spinning counterclockwise, that means that the storm formed north of the equator and formed south of the equator if it is spinning clockwise.
A storm reaches “tropical storm” status when winds reach 39 mph and is upgraded to a “tropical cyclone,” or in our case a hurricane, when wind speeds reach 74 mph. Hurricanes that reach categories 3, 4, or 5 are considered major hurricanes with the potential to have devastating or catastrophic damage. Click here to read more about the National Hurricane Center and how it uses the Saffir-Sampson Hurricane Wind Scale to categorize storms.