Updated April 03, 2025 at 15:04 PM ET
A series of storms is once again walloping the South and Midwest, bringing heavy winds, powerful rains and deadly tornadoes to multiple states.
The National Weather Service (NWS) Storm Prediction Center said it had received 27 reports of tornadoes in the 24-hour period between Wednesday and Thursday morning. At least four people were killed in western Tennessee and Missouri as of early Thursday, the Associated Press reports, as the NWS continued to warn of a "tornado outbreak" across the region.
The storm follows a series of devastating thunderstorms and tornadoes across the southern U.S. in March, which killed at least 42 people in seven states.
People following the news — and the forecasts — may be wondering: Is climate change making tornadoes worse?
After all, most of the extreme weather events that have dominated headlines recently — from heat waves to atmospheric rivers to historic floods — have had a clear connection to high temperatures, record rainfall and other effects of a warming planet.
Years of research have shown how climate change intensifies rain storms, heat waves and hurricanes, as NPR has reported.
The same can't exactly be said for tornadoes, however.
Scientists know that warm weather is a key ingredient in tornadoes and that climate change is altering the environment in which these kinds of storms form. But they can't directly connect those dots, as the research into the link between climate and tornadoes still lags behind that of other extreme weather events such as hurricanes and wildfires.
That's at least in part due to a lack of data — even though the U.S. leads the world in tornadoes, averaging about 1,200 a year.
Less than 10% of severe thunderstorms produce tornadoes, which makes it tricky to draw firm conclusions about the processes leading up to them and how they might be influenced by climate change, Harold Brooks, a tornado scientist at the National Severe Storms Laboratory, told The Associated Press in 2021.
Other factors that make that climate change attribution difficult include the quality of the observational record and the ability of models to simulate certain weather events. The National Oceanic and Atmospheric Administration says that's the case with tornadoes.
"The observational record is not consistent and relatively short, the models remain inconclusive as to replicating tornado activity, and our understanding of how global warming and climate change will influence the different atmospheric processes that produce tornadoes (wind shear, for example) is more limited," reads a page on its website.
Stephen Strader, a meteorologist and hazards geographer, told NPR in 2024 that as computational models improve, scientists are getting closer to being able to "see" the storms that produce severe weather.
"And hopefully in the future, we'll be able to actually see the ingredients that make up the tornadoes themselves within our models," said Strader, who is also a professor at Villanova University. "We're not there yet, but we're hopefully going to get there."
While scientists may not yet be able to conclusively connect tornado frequency or intensity to human-caused climate change, they say there are signs pointing in that direction.
Here's what they do know:
What tornadoes are and why they occur
NOAA defines tornadoes as narrow, violently rotating columns of air that extend from a thunderstorm to the ground (while the wind part is invisible, tornadoes can form condensation funnels of water droplets, dust and debris). They can be among the most violent of natural disasters, ripping homes apart, tearing through infrastructure and sending debris flying.
Tornadoes can occur in any part of the U.S. at any time of year.
They have historically been associated with the Great Plains, though experts say the idea of a so-called "Tornado Alley" can be misleading since the tornado threat is a bit of a moving target. It shifts from the Southeast in the cooler months of the year, toward the southern and central Plains in May and June, and the northern Plains and Midwest during early summer.
When people talk about "tornado season," they are usually referring to the time of year when the U.S. sees the most tornadoes — which peaks in May and June in the southern Plains and later in the northern Plains and upper Midwest.
Severe thunderstorms and tornadoes tend to start ramping up in the month of March (usually doubling from February), with the threat most concentrated in Southern states. That's the result of the clash between winter and spring weather patterns, with a still-strong jet stream and warmer air moving northward.
The month of March in recent years has been especially active, the Weather Channel notes: There were 236 recorded tornadoes in March 2022, the most in that month since 1950. March 2022 and 2023 had the most tornado fatalities of any month of the year (12 and and 47, respectively), it says.
The U.S. will likely see more tornadoes beyond their typical time and place
Experts say climate change is impacting the conditions in which tornadoes form and could lead to changes in when and where the U.S. sees them.
John T. Allen, a professor of meteorology at Central Michigan University, wrote in a USA Today opinion column that while ties to climate change are still uncertain, there appears to have been an "eastward shift in tornado frequency" and increasing frequency of tornadoes in outbreaks over the past few decades.
"Climate projections for the late 21st century have suggested that the conditions favorable to the development of the severe storms that produce tornadoes will increase over North America, and the impact could be greatest in the winter and fall," he added.
Brooks, of NOAA's National Severe Storms Laboratory, said the U.S. is likely to see more tornadoes in the winter as national temperatures rise above the long-term average.
Strader, the meteorologist, expects the next few decades will see an overall increase in the "number of days when we have the environment supporting severe weather," including tornadoes.
"So the reality is that we should see increases in the near future even though we haven't been able to detect much of a change in current-day or past studies," he said.
A version of this story first appeared in 2021.
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