Smog and Dust Particles Allow Twisters to Form

New research shows that pollution in the atmosphere is very likely to encourage the formation of wind swirls underneath super cell storm clouds. This leads to the formation of twisters, which pose significant risks to human lives and cause millions of dollars’ worth of damages each year, in the Midwest during the summer, and in the Southeast during fall and winter.
 

Microscopic dust particles are believed to play an important role in the complex interactions that go on inside storm clouds. Apparently, the presence of dust and other emissions in the atmosphere near these clouds prevents them from forming water droplets large enough to condense and fall to the ground. In turn, they lift to the higher part of the cloud, which leaves the downdraft currents free to swirl beneath the cloud.
 

If the entire formation is low enough, then the currents touch the ground, and start wreaking havoc, picking up materials as they go along. A new lab study, conducted by a team of researchers at the Colorado State University, led by David Lerach, showed the difference between clean and polluted air in the formation of twisters, via computer models. In the one that featured clean air, rain washed down and prevented the circular, upward motion of the air from occurring even once.
 

On the other hand, when dust concentrations were 10 times higher, like in the second model, twisters always formed. Though the researchers are not yet sure about how these twisters form, they do believe that higher concentrations of dust could lead to more such events.
 

In order to be sure, they would have to analyze the conditions near a small, unpolluted town, for example, as opposed to the conditions that occur near a heavily-industrialized site. Then, cloud formations and twister architectures would have to be compared. Until then, the team says that reducing the levels of dust in areas prone to these events is advisable.
 

"The model suggests if there's more [stuff] in the air, tornadoes are more likely to form. It raises interesting questions about the role of air pollution and aerosols in tornado genesis, but it doesn't prove anything," said Lerach.