Over the past few decades, tornadoes have been shifting—decreasing in Oklahoma, Texas, and Kansas, but spinning up more in states along the Mississippi River and farther east, a new study shows. Scientists aren't quite certain why, the AP notes. The study, which looked at changes since 1979, found everywhere east of the Mississippi, except the west coast of Florida, is seeing some increase in tornado activity. Tornado activity is increasing most in Mississippi, Arkansas, Tennessee, Louisiana, Alabama, Kentucky, Missouri, Illinois, Indiana, Wisconsin, Iowa, and parts of Ohio and Michigan, per a study in the Climate and Atmospheric Science journal. The four deadliest states for tornadoes are Alabama, Missouri, Tennessee, and Arkansas, per the NOAA. There's been a slight dip in the Great Plains, with the biggest drop in eastern and Central Texas.
Even with the decline, Texas still gets the most tornadoes. The shift may be deadly, as the area with increasing tornado activity is bigger and home to more people, per study lead author Victor Gensini. He adds that in those places, more people live in vulnerable mobile homes, and tornadoes happen more at night. Gensini and tornado scientist Harold Brooks examined "significant tornado parameters," a measurement of the key ingredients of tornado conditions that looks at differences between wind speed and direction at different altitudes, how unstable the air is, and humidity. The more of those three ingredients, the more likely tornadoes will form. Overall, there's a slight increase in tornado activity, but it's not nearly like what's happening in the east, Gensini says. Why is this happening? "We don't know," he says, though "this is super-consistent with climate change." (How RV parks are affected.)