Tropical storms and hurricanes kill people long after they’ve made landfall, according to a new study, adding to research suggesting storm-related deaths are chronically underestimated.
Columbia University environmental epidemiologist Robbie Parks and his team dug into 31 years of death records spanning more than 1,200 counties exposed to tropical systems in that time. They compared death rates in the weeks and months following storms to those rates in years without a storm.
The analysis offered quantitative evidence that death rates are elevated months later, Parks said, offering a glimpse of “wide-ranging and long” shadows that linger over communities.
“The data really strongly suggests that we should think of the health associations with hurricanes for many months, years and maybe even decades after a hurricane has hit a particular community,” he said.
The study found that death rates increased despite the storm’s severity, though the steepest change occurred in the aftermath of hurricanes. For example, injury-related deaths saw the highest increase in the month after a hurricane, jumping up by 33% compared to years without any storms.
Researchers also looked at deaths caused by infectious or parasitic diseases, cardiovascular disease, respiratory disease, neuropsychiatric conditions and cancer. Only cancer death rates saw no change in the six months after a storm. Every other category saw increases ranging from just under 5% to 11%.
Because of these changes, the study raises the question of whether the number of deaths associated with hurricanes is undercounted, possibly underselling their impact on parishes that are exposed. Looking at “excess deaths” after a storm might offer a “more complete picture of the burden of death and hospitalization of a hurricane passing through a community,” Parks said.
This study took a broader look at what smaller case studies have already examined. In New Orleans, a 2016 study by Tulane University doctors found that the number of heart attacks rose threefold in the years after Hurricane Katrina due to stress from living conditions after the storm, said Yvens Laborde, Ochsner Health’s medical director for global health education and public health.
“The interesting thing about mortality is how long out do you consider a mortality related to the actual event,” Laborde said. “There are a lot of long-term impacts that actually go beyond six months — they’ll go on for years, and we don't necessarily track it in reference to the event.”
Currently, coroners use their medical expertise to determine whether deaths that come through their office are considered “storm-related,” whether that’s from direct or indirect causes, noting it on the death certificate.
Direct deaths include drowning in floodwaters, being struck by fallen, wind-blown trees or electrocution from a downed powerline during the storm. Indirect causes — the ones highlighted by Parks’ study — are squishier.
Technically, any death resulting from unsafe conditions before, during or after a hurricane could be considered “an indirect storm-related death,” said Devin George, the Louisiana Department of Health’s state registrar of vital records. Those could be heat-related deaths or carbon monoxide poisoning from generators amid long power outages, falling from a ladder while repairing roofs, car crashes during evacuation or the heart attacks from stress centered in the Tulane study.
That can make them harder to capture, George said, and labeling a death as storm-related is at the discretion of the coroners.
Hurricanes Lauraand Idawere the deadliest hurricanes to strike Louisiana since Hurricane Katrina, with their official death tolls reaching 31 and 26 residents, respectively. But most of those deaths were attributed within one to two weeks after landfall, before the peak of elevated death rates in Parks’ study.
George said the state doesn’t place a cut-off for when a death is no longer considered storm-related — it falls on the coroner to decide.
“Think about someone replacing a roof right now, and that worker falls, hits their head and dies. Is that an indirect death or not?” asked George. “Some coroners may say yes, some may say no.”
Often, the answer is no, leading to smaller death tolls that Parks worries can water down the perception of a storm’s devastating impact.
Laborde agrees with Parks: it’s the indirect deaths that illustrate the importance of having strong support systems and infrastructure in place during hurricane recovery.
“It could easily be forgotten that people, for example, are left without housing and can't get access to that replacement housing or rebuilding because that resilience of the infrastructure isn’t there,” Parks said.
Laborde noted that discrepancies at the information-gathering level can hinder planning efforts that could help prevent deaths after the next disaster. With more and better data, they can better understand how to make a community more resilient before the storm hits.
“If we have a better idea of who's actually going to be adversely impacted — short, medium and long-term — then we can actually be predictive, and put things in place to protect both the individual and the communities that are impacted over time,” Laborde said.
They’re already doing this where they can, Laborde said. After Hurricane Ida, data collected by Oschner on the health risks facing vulnerable populations in coastal parishes helped them mobilize units soon after the storm passed to limit disruptions in care within areas that were already far from a healthcare center.
That quantifiable information can also offer evidence when advocating for the money to fund the preparation needed to respond after storms. And as hurricanes along the Gulf Coast become more intense due to climate change, Parks said understanding what’s needed to limit the loss of life associated with hurricanes will be critical to figuring out how to provide financial aid when communities are struck.
