Tropical cyclones leave a deadly legacy long after they pass

Tropical cyclones usually make headlines for their dramatic winds, wrecked buildings, and flooded streets. But new research shows that the real damage may continue long after the storm clears – and it’s not always the injuries you’d expect.

Deaths spike after a cyclone, not just from direct trauma, but from a wide range of health issues that don’t make the news. These issues include kidney failure, heart trouble, mental health breakdowns, and even diabetes complications.

Furthermore, these silent health threats hit hardest in communities with the fewest resources and the weakest healthcare systems.

Cyclones raise more than water levels

A team of researchers looked at death records from more than 1,300 communities across nine countries between 2000 and 2019.

Study lead author Wenzhong Huang is an expert in the School of Public Health and Preventive Medicine at Monash University.

The team studied 217 cyclones that struck parts of Australia, Brazil, Canada, South Korea, Mexico, New Zealand, the Philippines, Taiwan, and Thailand. In total, the analysis covered 14.9 million deaths.

The scientists mapped out wind and rainfall patterns for each storm. They matched those patterns to changes in death rates across leading causes of death. The results weren’t subtle.

The risk of dying shot up after a cyclone – especially in the first two weeks. Deaths from kidney diseases rose by a staggering 92% for each additional cyclone day in a given week. Deaths from injuries rose by 21%.

Other health problems also showed increased risk: diabetes (15%), neuropsychiatric disorders (12%), infectious diseases (11%), digestive diseases (6%), respiratory diseases (4%), cardiovascular diseases (2%), and neoplasms (2%).

The researchers behind the study point to a mix of factors, including disrupted essential healthcare services, limited access to medications, and increased physical and psychological stress.

Tropical cyclones in poor communities

One of the clearest findings was that poor and unprepared communities suffered most. Areas with fewer past cyclones and more economic deprivation faced significantly higher death rates after storms.

These places often lack the emergency response systems, health infrastructure, or backup power needed to protect people when things fall apart.

The researchers also found that rainfall – not just high winds – was strongly tied to death spikes. That’s likely because of flooding, contaminated water, and the difficulty of moving around when roads are submerged.

The results suggest that storm warnings should focus more on rainfall forecasts, not just wind speeds.

Rising threat in a changing world

Cyclones already affect an average of 20.4 million people a year. Over the past decade, they’ve caused around $51.5 billion in direct economic losses every year.

But this study adds something new: hard numbers showing that health systems can unravel under the pressure of a storm – and people die because of it.

What’s more, climate change is heating up the oceans, which gives tropical cyclones more energy. They’re becoming stronger, wetter, and slower-moving. That means more rainfall, more flooding, and longer-lasting damage.

“Overall, there is an urgent need to integrate more evidence on tropical cyclone epidemiology into disaster response strategies to respond to the growing risks and shifting activity of tropical cyclones under a warming climate,” wrote the authors of the study.

Access to health care after cyclones

When a cyclone hits, it doesn’t just knock things over and move on. It leaves people stuck in the aftermath – without power, clean water, or access to basic care. For anyone dealing with health issues, that’s a dangerous place to be.

Dialysis gets missed. Medications run out. Emergency rooms fill up or shut down completely. Even getting to a doctor can be impossible if the roads are washed out.

People aren’t dying just because of the storm – they’re dying because help can’t reach them, or they can’t reach help. That gap in care, even if it only lasts a few days, can push already fragile situations over the edge.

Building resilience against cyclones

The researchers make it clear: this wasn’t an experiment. It was an observational study. They can’t prove exactly what caused every death. But the patterns are strong and widespread across many countries.

“Taken together, these findings highlight the critical importance of indirect health effects of tropical cyclones, as many of the highest risk conditions do not stem from immediate trauma but rather from disrupted healthcare systems, environmental contamination, and prolonged stress,” wrote the researchers.

“We must translate these research insights into developing cyclone specific health policies that protect the most vulnerable, building resilience against the direct and indirect health impacts of these devastating events.”

The full study was published in the journal The BMJ.

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