Tropical storms cause many more deaths than officially recorded, according to a sobering study published today in the journal Nature. It comes as people across the southeastern United States are searching for their loved ones in the rubble of Hurricane Helene.
Researchers estimate that an average tropical storm or hurricane results in the early deaths of 7,170 to 11,430 people. That's astronomically higher than the average of 24 direct deaths per storm documented in government records spanning more than half a century.
“We were pretty stunned. So if people are surprised by these results, know that we were spot on too,” says study co-author Rachel Young, an environmental economist and postdoctoral researcher at the University of California, Berkeley.
“We were pretty stunned.”
In addition to the dangers of flooding and gale-force winds, people are likely to face many other insidious health risks after a storm. That's what researchers sought to capture with this study, hoping it can help officials anticipate these risks and perhaps prevent them in the future.
“Hurricanes and tropical storms have much greater public health impacts than we previously thought,” says Young. “People are at increased risk of death after these events for a very, very long time.”
Young and her co-author were also surprised at how long after a storm they found an increase in deaths – about 15 years. Their study includes data from all tropical cyclones – including hurricanes and tropical storms – in the contiguous U.S. between 1930 and 2015. They focused on changes in monthly state mortality rates for two decades following each of the 501 hurricanes during that period.
Crucially, they estimated the number of additional deaths – a figure that shows the number of deaths is likely accelerated by the lingering effects of a storm. The paper suggests several possibilities as to how these storms could have triggered these premature deaths. Added to this is the increased physical and psychological stress caused by the crisis. There can also be a cascade of additional environmental hazards, such as the release of chemicals from damaged industrial facilities. In addition, storms take a toll on people's wallets. This could make it more difficult for them to pay for health care. Disasters place strain on government budgets, which could also result in less funding being spent on public health initiatives. Finally, large storms can destroy social support systems as people are displaced.
In other words, they are indirect How a storm can lead to higher mortality rates. This differs from official storm death tolls, which typically only take into account immediate deaths from the devastation.
When looking at the Centers for Disease Control and Prevention (CDC) data they used in this study, researchers found that most indirect storm-related deaths listed the causes of death as “other.” It is a general category that may include sudden infant death syndrome, diabetes, suicide, or other causes. The second most common cause of death was cardiovascular disease, followed by cancer. Taken together, excess deaths associated with tropical cyclones account for between 3.2 and 5.1 percent of all deaths in the continental U.S., according to the study.
Some people are more susceptible than others, the study found. Across age groups, infants were at the highest risk of early death. Black populations also faced greater risks than white populations. This is consistent with existing health care disparities in the United States. For example, African Americans have lower rates of private health insurance than white Americans.
Southeastern states, which often bear the brunt of the Atlantic hurricane season, had the highest proportion of tropical cyclone-related deaths. Just last week, Hurricane Helene tore communities apart as it made its devastating path from Florida to Tennessee. The death toll is already over 160 and many more people are still missing.
This new research is a reminder that it will take years to recover from the disaster. “Hopefully this sheds light on the need to help people long after the first days and weeks of the storm,” Young said.
If there is a bright spot in the study, the data suggests how communities can become more resilient. The impact of tropical cyclones on mortality was actually lower in states where storms occur more frequently. The study suggests that people there likely minimized their risks by adapting to the climate. This ability to adapt will be even more important as climate change leads to more severe storms that can spread further inland and reach places that have not experienced such disasters in the past.
“It's a little more good news in a pretty bleak newspaper,” Young says. “States have the ability to adapt, and we’re actually seeing that in the data.”