That type of storm is called a supercell. Think of the large, rotating thunderstorms that fill the sky with a huge anvil-shaped, ominous gray cloud. Supercell storms can last for hours and bring about a twister.


Does climate change cause more tornadoes?

On a global scale, tornadoes are small weather events that begin and end within relatively short periods of time. It’s hard to connect those individual weather events to larger forces, like a changing climate. A clearer connection is found by studying the ingredients that come together to form tornadoes, according to Ashley.


“There’s a lot of steps in between those two,” he said. “The big fundamental question is, ‘is climate change contributing to the environments that support these, or sustain these, or make them more intense?’ The science really isn’t quite there yet.” This is because some of the factors that contribute to storms can be studied with global climate models, like temperatures and water vapor in the atmosphere. “Moisture is a slam dunk. It’s going to increase because we have a warming environment and warming oceans,” Ashley said.

Some research suggests that supercells in the U.S. have showed signs of change. Scientists at Northern Illinois University, including Ashley, compared years of those rotating thunderstorms. They also used smaller regional models and found that the number of supercells is likely to increase in frequency and intensity by the end of this century. The storms will be boosted by increased humidity and warmer temperatures.


John T. Allen, a meteorology professor at Central Michigan University, said that studying supercells is great, but it’s still not always clear if a tornado will form. As few as 20% of supercells create tornadoes, according to the National Oceanic and Atmospheric Administration. “[Sometimes] the Storm Prediction Center might even need to issue a tornado watch, and nothing happens,” Allen told Earther. So while the storms and storm environments are easier to study, researchers are still gathering data and learning about tornadoes. “The research is much younger than the field for hurricanes and for temperature,” he said.

“I think we’ll get there one day,” Ashley told Earther. “But even if the science advances, you’re going to be hard pressed to say, ‘5% was due to climate change’, or whatever the contribution might be.”