Hurricane Helene Deaths Will Continue for Years, Study Suggests

Over the past week, the official death toll from Hurricane Helene has surpassed 100 as the vortex creeping inland from Florida submerged homes and swept away cars. But the full weight of lost lives will be realized only years from now — and it could number in the thousands.

A paper published in the journal Nature on Wednesday lays out the hidden toll of tropical storms in the continental United States. Looking at 501 events from 1930 to 2015, researchers found that the average tropical storm resulted in an additional 7,000 to 11,000 deaths over the 15 years that followed.

Overall during the study period, tropical storms killed more people than automobile crashes, infectious diseases and combat for U.S. soldiers. It’s such a big number — especially compared with the 24 direct deaths caused by hurricanes on average, according to federal statistics — that the authors spent years checking the math to make sure they were right.

“The scale of these results is dramatically different from what we expected,” said Solomon Hsiang, a professor of global environmental policy at the Doerr School of Sustainability at Stanford University, who conducted the study with Rachel Young, the Ciriacy-Wantrup postdoctoral fellow at the University of California, Berkeley.

The pair used a technique that has also provided a more complete understanding of “excess deaths” caused by Covid-19 and heat waves. It works by looking at typical mortality patterns and isolating anomalies that could have been caused only by the variable under study — in this case, a sizable storm.

Previously, researchers examined deaths and hospitalizations after hurricanes over much shorter periods. One study published in Nature found elevated hospitalizations among older Medicaid patients in the week after a storm. Another, in The Journal of the American Medical Association, associated higher death rates with U.S. counties hit by cyclones. A study in The Lancet found that across 14 countries, cyclones led to a 6 percent bump in mortality in the ensuing two weeks.