Learn about these violent storms and why they’re dangerous.
Every year, coastal regions brace themselves for violent windstorms known as hurricanes. But how do these storms form and grow?
The oversimplified answer: Warm ocean water plus the Earth’s eastward rotation.
“They’re heat engines,” said meteorologist Jeff Masters of the website Weather Underground in a previous interview. “They take heat from the oceans and convert it to the energy of their winds. They’re taking thermal energy and making mechanical energy out of it.”
The natural engine that is a hurricane is fueled by warm, moist air. The storms move heat from the ocean surface high into Earth’s atmosphere. They can travel thousands of miles from the tropics toward the Earth’s poles.
According to NOAA’s National Hurricane Center, the average hurricane eye—the still center where pressure is lowest and air temperature is highest—stretches 20 to 30 miles across, with some even growing as large as 120 miles wide.
The strongest storms, equivalent to Category 5 on the Saffir-Simpson scale, have sustained winds that exceed 155 miles an hour.
Why Are Hurricanes Dangerous?
While hurricanes are categorized based on their wind speeds, wind isn’t typically the most dangerous part of such storms. “It’s the storm surge,” said Kerry Emanuel, an atmospheric scientist at MIT, in an earlier interview. The storm surge is the bulge of water built up in front of a cyclone or hurricane courtesy of its winds.
It’s the number one killer in hurricanes, Emanuel explained. “That’s what killed people inKatrina, it’s what killed people in Sandy and in Haiyan.” (Read “Charts Show How Hurricane Katrina Changed New Orleans.”)
Emanuel likened a storm surge to a tsunami. One just happens to be caused by earthquakes (tsunamis), while the other is generated by hurricanes.
Then comes wind that blows around debris. Hurricane Andrew in 1992 is an example of this. “It didn’t really cause too much of a storm surge,” the atmospheric scientist said, “but boy did it blow a lot of buildings down.”
Climate change will likely increase the frequency of “the high-end hurricanes,” Emanuel said.
And those powerful storms have the potential to produce a lot of rain, flooding, and strong storm surges.