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Hurricanes: How They Form

What generates a hurricane and how does it strengthen? What exactly is a hurricane?

These are common questions that come up during hurricane season, which runs from June through November. This article aims to answer these questions and others.

A typical hurricane will form from an area of low pressure originating from the tropics, where there is ample moisture. As it crosses over warm waters, the heat is lifted up into the storm and causes lower pressure to form beneath it. This sucks in more moisture and heat, enhancing the growth of the storm. 

Once the air cools up in the clouds, thunderstorms begin to form, and as that happens, the moisture droplets that are forming release heat back into the storm. 

Eventually, it will organize and strengthen enough that it establishes a defined center and circulation around it, making it a tropical cyclone.  

Classifications of tropical cyclones

In the North Atlantic and Eastern Pacific, which are under the watch of the National Hurricane Center based out of Florida, there are three stages of cyclones:

1. Tropical depression: These have winds of up to 39 mph and are typically unorganized.

2. Tropical storm: With winds of 39 mph to 73 mph, they can pack serious winds and flooding.

3. Hurricanes: A cyclone is called a hurricane once it has winds of 74 mph or greater. These are the most dangerous, with strong winds and flooding rains.

If a hurricane reaches winds of 111 mph or greater, it is called a Major Hurricane. 

Center of a hurricane

The classic eye will you know of from hurricanes only occurs once the hurricane attains great strengths and intensities. Most hurricanes won't have a very clear eye.

The eye is the center, where it is more calm. The hurricane spins around this eye, sucking up moisture and heat from the center, distributing it to the outer bands.