In August 2023, downed power lines on Maui, Hawaii, sparked a wildfire that quickly exploded into multiple, fast-moving blazes fanned by high winds. Over several days, the fires reduced much of the town of Lāhainā to ashes, displacing thousands and killing more than 100 people.

New research published Thursday, August 22, in the journal Frontiers in Climate suggests this disaster also caused a population-wide increase in mortality beyond what the official death count captured. By calculating the all-cause excess fatality rate—how many more deaths took place over a given period than expected—scientists found a 67% increase in the local mortality rate for August 2023. During the deadliest week of the blaze, the local death rate was 367% higher than expected. These findings underscore a need for improved disaster preparedness that incorporates Native Hawaiian ecological knowledge, the researchers concluded.

What excess death rate reveals

Looking at the excess death rate offered a fuller picture of the fire’s impact, co-first author Michelle Nakatsuka, a medical student and researcher at New York University’s Grossman School of Medicine, told Gizmodo in an email. “The official numbers mostly count direct causes, like burns or smoke inhalation, but excess deaths capture [the] true toll better by telling us how many more people died than would have otherwise been expected in the month of the Lāhainā fires,” she explained.

Disasters like wildfires often cause deaths in indirect ways that affect communities over time. When clinics shut down and roads are blocked off, people can’t refill their prescriptions or get dialysis treatments, Nakatsuka explained. Stress and displacement can worsen chronic conditions, and power or communication failures can delay emergency responses. “These impacts are amplified in under-resourced settings and [are] disproportionately suffered by vulnerable groups, like the elderly or people of color,” she said.

The tragic toll of the Maui fires

Even with this knowledge, Nakatsuka and her colleagues were surprised by the increase in excess mortality during the month of August 2023. Their analysis included all causes of death except covid-19. “While we anticipated an increase in excess deaths, seeing more than 80 additional deaths in the month of the Lāhainā fires was striking,” Nakatsuka said. “It was also surprising to see that the proportion of those deaths occurring outside of medical settings was larger than expected,” she added.

Indeed, the number of deaths that didn’t take place in a medical context—such as the emergency room—rose from 68% in previous months to 80% in August 2023. These people died in homes or public locations, suggesting that many were unable to reach medical care because of the fires.

A path to resilience

While all-cause excess mortality is useful for correlating increased fatalities with natural disasters, it offers little insight into the details of these deaths, Nakatsuka clarified. “The main limitation here is that we can’t say exactly which deaths were caused by the fires or look into Lāhainā-specific excess mortality; we can only measure the overall increase in deaths,” she said, adding that future research should analyze death records alongside medical and toxicology reports to identify causes of death.

Still, these findings reveal a need to improve Maui’s disaster preparedness and invest in wildfire mitigation strategies rooted in Indigenous knowledge, Nakatsuka said. “Native Hawaiian practices center around caring for the land (mālama ʻāina) in ways that naturally reduce fire risk, like restoring native plants, maintaining diverse ecosystems, and managing water resources,” she said. “Bringing Indigenous knowledge together with modern climate prediction tools will minimize risk of future climate crises and center the community’s voice at the heart of disaster prevention and recovery efforts.”