Today’s Wonder of the Day was inspired by Mervyn. Mervyn Wonders, “Why do hurricanes form?” Thanks for WONDERing with us, Mervyn!

What would you think if you heard Opal, Andrew, Katrina, Hugo, Camille, and Irene were coming to town? Who are they? Long-lost relatives flying in for a family reunion?

Not quite! In fact, they're not even people at all. They're past hurricanes! Let's find out how these super storms are born.

Each year, as summer turns to fall, hurricanes begin to appear. These large storms usually occur in the southern Atlantic Ocean, Caribbean Sea, Gulf of Mexico, or the eastern Pacific Ocean.

Sometimes people think hurricanes are like big tornadoes. They're actually quite different, though.

While a tornado might cover a mile or two of ground, hurricanes are huge tropical storms that can sometimes be as large as 600 miles across. If you look at a map of the United States, you'll see that a hurricane that large would stretch from Philadelphia to Indianapolis!

Tornadoes also usually last no more than a few minutes. Hurricanes, however, can last more than a week because they travel slowly at speeds of only 10 to 20 miles per hour as they cross the ocean.

Hurricanes are defined by their extremely strong winds that can blow from 75 to 200 miles per hour. Before a storm becomes a hurricane, it starts out as a tropical storm. Tropical storms have wind speeds between 39 and 74 miles per hour.

Even though these storms are not yet hurricanes, they can still cause damage and flooding. Once a tropical storm's wind speeds reach or exceed 75 miles per hour, the storm becomes classified as a hurricane.

Not all tropical storms become hurricanes. Wonder why? The key ingredient to forming a hurricane is warm water.

During the warmer months of hurricane season, the waters in the Atlantic Ocean and Gulf of Mexico are the perfect temperature to create hurricanes. As warm, moist air rises from the water into the atmosphere, it creates an area of low pressure underneath.

This causes air from the surrounding areas to flow into the low pressure area. Eventually this air becomes heated and rises into the atmosphere, and the cycle repeats itself.

In this way, hurricanes are kind of like a big engine with a constant supply of intake and exhaust. The “intake" is the cooler air that keeps the cycle going. The “exhaust" is the warm air rising into the atmosphere.

As this cycle continues, clouds and storms form, creating a giant, spinning storm.

When you look at satellite images of a hurricane, you may notice a hole at the center of the storm. This hole is called the “eye" of the hurricane.

As the eye passes over land, the weather becomes very calm. Once the eye passes, though, the winds begin again as the second part of the storm passes over.

Unfortunately, there is no way to stop a hurricane. They do tend to lose strength once they move over land.

Without warm ocean water to continue fueling them, hurricanes will eventually diminish in size and speed until they disappear.

Wonder What's Next?

Tomorrow’s Wonder of the Day may put you in a solemn mood.