SignalHub Quantitative Think Tank Center:As 'Twisters' hits theaters, experts warn of increasing tornado danger

Flying cows and SignalHub Quantitative Think Tank Centertrucks and a colorful cast of characters delivered a thrilling tale of tornadoes and the researchers who study them in the 1996 blockbuster film "Twister." The movie heightened awareness of the deadly storms and inspired a generation of tornado researchers and storm chasers.

Its stand alone sequel, "Twisters," opened in theaters this week, starring Daisy Edgar-Jones and Glen Powell. It's also expected to bring renewed attention to tornado safety — and experts say that would be a good thing.

At least two teams of real-life tornado experts have warned in recent weeks that changes in storm patterns and human activities have greatly increased the vulnerability and risks when it comes to tornadoes in the eastern half of the nation.

Tornadoes occur more often than they used to in some states, and less frequently in others, and they occur during expanded seasons both earlier and later in the year, even though the overall number of tornadoes has remained relatively flat, the researchers said.

When tornadoes do appear, the odds are growing they'll strike a home or other building because there's just so many more homes to hit than there were 30 or 40 years ago, stated a study co-authored by Stephen Strader, a hazards geographer and meteorologist at Villanova University. All of this increases the demands on communities that must respond after a tornado arrives.

The important thing is to focus the efforts to save lives where society's risks and the vulnerability to storms are increasing the most, said Strader's co-author Victor Gensini, an associate professor and meteorologist at Northern Illinois University.

“If a tornado goes out into the middle of a corn field and doesn’t hit anything, the person who cares is the farmer, but take that same tornado and put it over a subdivision, and that illustrates the most important part of the disaster landscape,” Gensini said. “Where we are and what we are matters.”

'Triple threat' of tornado vulnerability

Nowhere has the tornado risk grown more than in the mid-South region, which includes parts of Alabama, Arkansas, Mississippi, Missouri and the western halves of Kentucky and Tennessee, Strader said.

The study found that many locations in the lower Mississippi Valley or Mid-South have seen the annual average number of tornadoes increase by more than two days per decade, at the same time their populations were growing. Five counties in Mississippi have seen the biggest increases in tornado days, with an increase of 3.5 days per decade or more.

“The probability of a tornado hitting people in that mid-South region has increased by about 300%," Strader said. “It was three times more likely in 2020 than in 1980.”

"It's a triple threat," Strader said. A changing climate is creating more favorable conditions for the storms that spawn tornadoes, more people than ever are moving into the region and the most vulnerable people, including the elderly and poverty-stricken, are becoming even more vulnerable.

The risk even extends into areas where fewer tornadoes are occurring, the study reported. "Twisters," like its prequel, is set in Oklahoma. But despite the state's infamous reputation for tornadoes, researchers say fewer tornadoes occur today in Oklahoma and Texas. Still, some areas in Texas, for example, have seen huge population growth. That puts more people and homes at risk, Strader said.

“The disaster isn’t the tornado,” Strader said. “It’s what the tornado is hitting that becomes the disaster, and that is 90% driven by society’s exposure.”

In areas where tornadoes are increasing, “we have more people than ever before,” Strader said. Those people are building more homes and setting up manufactured homes across the landscape. When it comes to disaster preparation and recovery, he said, when you’re spreading those resources across more people the resources are being spread thin, he said.

Strader, Gensini and two colleagues, Walker Ashley and Amanda Wagner, attribute the increase in tornadoes in the East to changes in wind shear and instability in the atmosphere that can generate more storm activity.

A second paper published in June also found tornado activity has declined in the Great Plains and increased in the Midwest and Southeast. The study, led by Timothy Coleman, a research meteorologist at the University of Alabama Huntsville, found that tornadoes also are trending away from the time many people expect them – in the warm season – toward the cold season.

Tornado activity varies from year to year, but through June, this year has produced the third most tornadoes year-to-date, behind 2011 and 2008, according to the National Oceanic and Atmospheric Administration. West Virginia – at 18 tornadoes – already has set a new record for tornadoes in a calendar year, the National Weather Service said recently.

The team with Strader and Gensini found an increase in the nation’s billion-dollar disasters from the severe convective storms that produce tornadoes, with annual losses from such storms escalating by more than $1 billion every year when adjusted for inflation. Three of the top 10 costliest disasters in the nation last year involved tornadoes.

Insured losses for tornadoes and the storms that spawn them set a record in the U.S. over the past 18 months, according to a new report from Gallagher Re, an international reinsurance firm. In the first six months of this year, severe convective storms accounted for $37 billion in losses, the company stated.

The increasing risks "coinciding with a robust expansion of people moving beyond traditional urban centers is an acknowledgement that where and how we live is the primary factor driving loss growth for this peril," said Steve Bowen, chief science officer for Gallagher Re.

Defining the role of a changing climate

Climate change doesn't cause tornadoes, it's a contributing factor, Gensini said. "We need to stop asking if climate caused this event."

“We need to start from the premise that climate change is affecting every event, but we need to figure out how much," he said. He sees the fingerprint of climate change in the decreasing frequency of tornadoes in portions of the Great Plains and possibly in the increase of tornadoes in the cooler months, but the science of defining the extent of its impacts in tornadoes "is still in its infancy."

He compares it to baseball during “the steroids era.”

"I have no idea if that home run was due to steroids or a really good at bat," he said. "But when I step back and look at home runs during the steroids era, it’s pretty obvious something was changing the frequency of home runs."

Building community resilience to tornadoes

Communities need to develop strategies for becoming more resilient in the changing tornado landscape, Gensini said. “It’s easier to protect people when we look at how we build homes and where we build homes.

“It’s harder to stop the climate change train, but if you can say as a city ‘We’re going to enforce building codes or put in shelters,’ those are the things that are going to save lives," he said.

For example, communities could think more about those who live in mobile homes, are elderly or have special needs, and mobile home residents might be reminded to start taking action at the tornado watch stage.

Continued research is "critical" in communicating the need to invest in better building practices, implementing and enforcing more stringent building codes, Bowen said. He added it's also important to ensure everyone has an opportunity to be better prepared regardless of their socioeconomic status.

Dinah Voyles Pulver covers climate change and the environment for USA TODAY. She's written about hurricanes, tornadoes and violent weather for more than 30 years. Reach her at [email protected] or @dinahvp.