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What Are the Physical Factors That Help a Hurricane Form?

Hurricanes are a circular movement of air that forms near the warm oceans close to Earth's equator. Some remain at sea, but others move inland and can cause a lot of damage. Hurricane Katrina, which formed in the 2005 Atlantic hurricane season, is one hurricane that passed over land and was the costliest natural disaster in the history of the United States.There are six main factors that help create a hurricane. Instability in the atmosphere is the main thing needed to form a hurricane, and each of the six factors contribute to this in some way.

Warm Ocean
- The temperature of the sea must be at least 80 degrees Fahrenheit to a depth of 165 feet. A warm ocean allows the air above it to become unstable, meaning convection can occur. Convection is needed for thunderstorm activity, which in turn is needed to trigger the formation of a hurricane. If the sea surface temperature was below 80 degrees the air above it would be too stable and a hurricane would not form.
Humidity
- Humid air helps hurricanes to form. Moist layers in the atmosphere at around 3 miles above the sea are needed for the atmosphere to become unstable enough for thunderstorm activity. Thunderstorm activity is a precursor to hurricane formation, so dry air will prevent a hurricane from forming.
Wind Shear
- Hurricanes need something known as weak vertical wind shear to form. Shear occurs when one layer of air moves over another, causing friction between the two layers. You can use it to compare different wind speeds over a certain height. Weak vertical wind shear disturbs the air in the atmosphere, creating conditions in which a hurricane can form. However, too much shear can prevent a hurricane from forming or destroy one that is just beginning to form.
Location
- Hurricanes can form only at latitudes at least 300 miles from the equator. This is because of the Coriolis effect, which occurs in all rotating systems. In this case, we see the Coriolis effect because of wind that makes the atmosphere rotate. The Coriolis effect helps hurricanes to form, but it only occurs at latitudes at least 300 miles from the equator.
Easterly Wave
- Easterly waves are large areas of low pressure air in the atmosphere that form over North Africa. They occur mainly in the summer and can result in a lot of rainfall. Easterly waves disturb the air in the atmosphere as they move across the ocean and create vortices. Vortices make the air rotate and become unstable, and they can help hurricanes to form. According to the Hurricane Research Division of the Atlantic Oceanographic and Meteorological Laboratory, nearly 85 percent of major hurricanes started out as easterly waves.
Cool Atmosphere
- Hurricanes cannot form spontaneously from still air. If the atmosphere above the warm ocean gets cooler the higher you go, air in the atmosphere can move around by convection. Convection happens because the warm air close to the ocean rises, making room for cold air next to the ocean. The ocean then warms to cold air and the process repeats. Convection makes the atmosphere unstable and helps hurricanes to form.

Nature