Science explains why hurricanes even exist

Storms balance atmosphere’s temps by moving heat to polar areas

Hurricanes have pummeled sea and land on Earth for eons. Why do these meteorological monsters even exist?

Simply put, hurricanes are the atmosphere’s attempt to move heat from the warm equatorial regions toward the cold polar regions, said meteorologist Phil Klotzbach of Colorado State University.

It’s one of the ways the atmosphere keeps its heat budget balanced, he said. In the winter, that can be done by storms such as nor’easters or blizzards, and in the summer it’s through hurricanes.

Tropical cyclones — an umbrella term that includes tropical storms, hurricanes, typhoons and cyclones — are giant engines that convert the energy from warm air into powerful winds and waves. That’s why they form only over warm ocean waters near the equator.

The tropics near the equator supply the ingredients for tropical cyclones: wide expanses of warm ocean water, air that’s warm and humid and normally weak upper-air winds blowing from the same direction as winds near the surface, Jack Williams noted in the

USA TODAY Weather Book.

Hurricanes tend to be most intense and frequent in the late summer and early fall, when ocean water is at its hottest, Massachusetts Institute of Technology hurricane expert Kerry Emanuel said in an interview with the Annenberg Foundation.

From a physics standpoint, he said a hurricane is a “heat engine. It’s a massive, natural machine for converting heat energy into mechanical energy — the mechanical energy being the energy of the wind.”

In addition, hurricanes don’t just transport heat to the poles. “They also help radiate that heat out of the tropics into space,” meteorologist Ryan Maue said.

Klotzbach said the storms provide a small percentage — about 2% — of global rainfall during the peak months of the hurricane season.

A hurricane is “a massive, natural machine for converting heat energy into mechanical energy — the mechanical energy being the energy of the wind.”

Kerry Emanuel, Massachusetts Institute of Technology