America’s tornado danger zone could engulf a vast new swath of the country late this century as conditions that fuel devastating outbreaks shift north and east.
The chilling warning comes from researchers who used a climate model that found outbreak-supporting conditions could expand across the Midwest, Great Lakes and Northeast.
Tornado Alley traditionally stretches through the central Great Plains, including Texas, Oklahoma, Kansas, Nebraska and South Dakota, while the Southeast has its own deadly corridor, known as Dixie Alley, covering states including Mississippi, Alabama and Tennessee.
Under the new projections, dangerous conditions could become more common across Missouri, Illinois, Indiana, Iowa, Minnesota and Wisconsin, while reaching as far east as Pennsylvania and New York.
The changes are forecasted between 2065 and 2099 and apply specifically to May, historically the peak month for major US tornado outbreaks.
Researchers linked the potential shift to a warmer, wetter atmosphere and changing jet-stream and wind patterns, while stressing that traditional tornado zones would not necessarily become safer as the threat expands.
Dr Jana Houser, associate professor of meteorology in the atmospheric sciences program at The Ohio State University, who was not involved in the study, told Daily Mail: ‘Frankly, the entire eastern half of the country should have a conversation about what the potential for increased tornado activity might mean for families and communities.’
‘Everyone should have plans in place and take tornado risks seriously, even if your local community is traditionally not prone to tornado activity. It only takes one tornado to change lives.’
Houser cautioned that the study tracks changes in tornado-supporting weather, not how many twisters each region will see.
‘This study specifically suggests that tornado-supportive environments might increase in frequency in the Midwest US in the future,’ she said.
The Plains could still record the nation’s most tornadoes.
The study, published in npj Climate and Atmospheric Science, involved researchers from the University of Oklahoma, MIT, NOAA and NASA.
The team analyzed the atmospheric patterns surrounding 45 major May outbreaks between 1980 and 2014, then tested that fingerprint in a high-resolution global model under four emissions pathways.
With intermediate emissions, favorable conditions spread from eastern Texas and Oklahoma through the Mississippi and Tennessee valleys and as far east as Virginia, Pennsylvania and New York.
Higher emissions shifted the core northeast, with significant increases in Tennessee, Kentucky and southern Illinois and Indiana.
Extreme warming produced the widest footprint, with the largest gains in Wisconsin, Minnesota, Iowa and Illinois and the strongest signal in eastern Missouri.
Under the new projections, dangerous conditions could become more common across Missouri , Illinois , Indiana, Iowa, Minnesota and Wisconsin , while reaching as far east as Pennsylvania and New York. Above is a tornado that hit New York this month
The warning comes from researchers who used a climate model that found outbreak-supporting conditions could expand across the Midwest, Great Lakes and Northeast. Above is the aftermath of a tornado that barreled through Aroma, Park Illinois in March
The study’s lead researcher, Paulina Cwik, told Daily Mail: ‘What stood out to me was how the projected patterns spread farther north and east while still remaining present in areas that already have been at higher risk of major outbreaks.’
‘So, rather than seeing one tornado-prone region simply replaced by another, our study suggests that the atmospheric patterns associated with major outbreaks could extend across a broader geographic area.’
Western Florida showed the opposite trend, recording a decline in outbreak-supporting conditions.
Houser linked the changes to shifting wind patterns that control atmospheric moisture and wind shear, two key ingredients for organized, rotating thunderstorms.
Warmer air can hold more moisture, while movement in the jet stream and Great Plains low-level jet could redirect that fuel and alter crucial wind shear.
However, extreme warming could eventually weaken some of those ingredients by reducing midlatitude wind shear and strengthening the atmospheric ‘cap’ that can stop storms from forming.
That may explain why the model identified 80 outbreak-proxy days historically, rising to 85 under the lowest-emissions pathway, 100 under the intermediate pathway and 112 under the high pathway before falling to 93 in the most extreme scenario.
‘I was also surprised that the relationship with future climate scenarios was not simple,’ Cwik said. ‘The highest-emissions scenario we examined did not produce the largest number of outbreak-supportive days.
‘Instead, the results varied across scenarios, both in the number of outbreak-supportive days and in how the associated atmospheric patterns were organized geographically.’
Those totals span separate 35-year periods and include proxy days occurring in different locations from one year to the next.
‘They highlight that there is substantial interannual variability from year to year, meaning that one year’s outbreak numbers might be very low while another’s are very high,’ Houser said.
Missouri was also forecasted to see more tornados. Above are cyclones captured in Unionville in June
‘Furthermore, the outbreak locations do not necessarily occur in the same locations from year to year.’
In annual terms, the totals represent an increase from 2.29 outbreak-supporting days each May historically to between 2.39 and three days in the future simulations.
The rise was not statistically significant because tornado-supporting weather varies dramatically between years, making the redistribution of favorable conditions a more reliable finding than any increase in outbreak frequency.
Still, Houser said some scenarios support an increase in those days, although researchers cannot determine which areas would experience more or fewer tornadoes.
The area exposed on each proxy day expanded from roughly 328,000 square miles historically to about 386,000 under the low-emissions pathway and 402,000 under the intermediate scenario, an increase of up to 22 percent.
Houser said a larger footprint could place more people at risk but stressed that the model cannot resolve the small-scale ingredients that determine whether a tornado forms.
‘Tornado formation is incredibly sensitive to very small-scale details of environments, storms, and even physical conditions on the ground such as land cover and terrain,’ she said.
Researchers linked the shift to a warmer, wetter atmosphere and changing jet-stream and wind patterns, while stressing that traditional tornado zones would not necessarily become safer as the threat expands. Above is the aftermath of a tornado in Wisconsin last month
‘You can have six storms in what appears to be the same environment on the spatial scale that this study is working with, and only 2/6 storms produce tornadoes,’ Houser added. ‘Why? We don’t entirely understand that yet.’
The figures represent scattered model grid cells containing key outbreak ingredients, not the path of one storm or a continuous tornado warning.
Under the most extreme pathway, the portion of the study area exceeding one high-end atmospheric threshold rose from 3.3 percent to 8.1 percent, a 146 percent increase.
Cwik said that figure points to a reorganization of the broader atmospheric pattern, not proof that individual outbreaks will cover more territory.
‘Our analysis does not allow us to say that a future tornado outbreak will necessarily cover a larger area, produce more tornadoes, or expose a specific number of additional people,’ she said. ‘Answering that would require storm-resolving simulations together with population and exposure analyses.’
The researchers also stressed that a stronger modeled signal does not mean individual tornadoes will become more violent.
‘Global climate models cannot explicitly simulate individual tornadoes, and our method does not represent storm-scale processes such as convective initiation or low-level rotation,’ Cwik said.
‘Therefore, we interpret our results as changes in outbreak-supportive atmospheric patterns, rather than direct projections of future tornado occurrence or intensity.’
The study used only one model, examined only May and relied on fixed thresholds that may behave differently in a warmer atmosphere.
People help to clear away damage after a tornado hit New York’s Atlantic Beach in August
‘The projected changes are also scenario-dependent and come from a single climate model, so they should not be interpreted as a multi-model consensus on future tornado outbreak behavior,’ Cwik said.
Its findings therefore amount to a proof of concept rather than a settled forecast of where tornadoes will strike.
‘Models help us understand possible outcomes of the future state of the atmosphere… but they cannot be taken as a crystal ball,’ Houser said.
She called for the analysis to be repeated across every month using different model configurations.
‘When different models converge on similar solutions, the probability of that outcome coming to fruition increases,’ Houser explained. ‘So we should move forward cautiously, but with an eye towards preparedness and preparation.’
