Where severe weather happens

Research has found that tornado activity is shifting east. Comparing 1979 to 2017, Dr. Vittorio Gensini of Northern Illinois University and Dr. Harold Brooks of NOAA's National Severe Storms Laboratory found significant increases in tornado reports and tornado environments across Mississippi, Alabama, Arkansas, Missouri, Illinois, Indiana, Tennessee and Kentucky, and decreases across parts of Texas, Oklahoma and northeast Colorado. They tied the change to climate change: they found a climate change signal in the data, and Dr. Gensini has said climate change is a reasonable explanation for the eastward shift, with computer simulations supporting what is observed and what is expected.

A 2024 study in the Journal of Applied Meteorology and Climatology compared 1951 to 1985 with 1986 to 2020. The largest decrease ran from eastern Kansas through Oklahoma into north Texas; the largest increases were in the Southeast, centered on Mississippi and Alabama. Tornadoes also shifted toward the cold season, with the share of tornadoes in the cold months rising from about 20% to about 28%.

Climate model studies point the same way. Research led by Dr. Walker Ashley, Dr. Alex Haberlie and Dr. Gensini, published in the Bulletin of the American Meteorological Society in 2023, projects supercells becoming more frequent and more intense in a warmer climate, with increases in the eastern United States, decreases in parts of the Great Plains, and more activity in late winter and early spring.

The shift matters because the Mid-South and Southeast have more people, more mobile homes, more trees blocking the view of a tornado, and more tornadoes at night than the traditional Plains alley.

Try it on the map: choose Compare periods, Days and Strong, then compare 1966 to 1980 with 2011 to 2025. Red hexes gained tornado days; blue hexes lost them.