Satellite image of Hurricane Dora (photo: NOAA)

Public Health Scientists Chart the Destructive Power of Hurricanes

August 16, 2023

As climate change warms the oceans, hurricanes like the one that fueled deadly wildfires in Maui are increasingly common—and deadly. More than 100 people have died from the blazes, which spread from a combination of high winds and invasive grasses dried out by drought.

A new study by Robbie M. Parks, Columbia Mailman assistant professor of environmental health sciences, and colleagues examines hurricanes affecting the United States between 1988 and 2019, finding that 83 percent of the resulting deaths happened in the six years beginning in 2004. And 94 percent of these deaths took place in socially vulnerable counties, when measuring by those with the largest proportion of residents who are people of color.

The single largest number of excess deaths (those above the normal death rate) was in Orleans Parish, Louisiana, after Hurricane Katrina in 2005, with 719 excess deaths, followed by Harris County, Texas, after Hurricane Rita in 2005, with 309 excess deaths.

“In our study, excess death counts after tropical cyclones were higher more recently and for the most socially vulnerable,” said Parks, the study’s first author. “This was likely in part due to lack of access to adequate short-term transportation, as well as inequitable access to financial resources, education, employment opportunities and timely warnings on tropical cyclone proximity, all of which are results of long-term institutional neglect.”

“It is also essential to prepare for tropical cyclones by accounting for the social determinants of risk and vulnerability of exposed communities, since the most socially vulnerable bear the greatest burden of excess mortality,” noted Marianthi-Anna Kioumourtzoglou, associate professor of Environmental Health Sciences and senior author.

The Lahaina area of West Maui devasted by the recent wildfires is revered by its Indigenous peoples as a sacred place for generations and in the 19th century served as the home and burial place of the Hawaiian royal family and the first capital of the Hawaiian Kingdom. According to reporting by the New York Times, the area has the county’s highest rate of non-English speakers and the second-highest rate of households without a vehicle.

Following a tropical cyclone, deaths can result from injuries, infectious and parasitic diseases, cardiovascular diseases, neuropsychiatric conditions, respiratory diseases, and more. In earlier research published In JAMA and Nature Communications, Parks and colleagues detailed the kinds of causes and risks for death that increased after the storms. Of course, tropical storms are only one of the destructive consequences of climate change; this summer has seen record temperatures, smoke conditions, and flooding associated with poor outcomes

Another study published in the journal Emerging Infectious Diseases by postdoctoral research scientist Victoria Lynch and Jeffrey Shaman, professor of environmental health sciences and interim dean of the Columbia Climate School, found that tropical cyclones promote the spread of waterborne infectious diseases.

While hurricanes are not rare in the Pacific; Maui hasn't had a hurricane in over 100 years—which is why the storm took Hawaii by surprise. Hurricane trajectories are complex and often difficult to predict, however, the physics that drives them is straightforward. Warmer waters contain more kinetic energy, which is the engine room for these devastating storms.

With warmer waters, hurricanes will likely become stronger, emerge more quickly, and affect areas where they aren’t expected. Waters like those off of Florida, which exceeded 100 degrees Fahrenheit this summer, could easily give rise to powerful storms.

“Hawaii is an emergent tropical cyclone threatened area due to climate change, and that historically this hasn’t been the case, so the resilience built up in regularly hit areas of the United States will take time to build in Hawaii,” says Parks. “Nevertheless, there are limits to preparedness, particularly when resources are inequitably distributed, and we are seeing that climate change-fuelled tropical cyclones seasons are pushing some areas of the United States, particularly in the South and Southeast, a limit of adaptability.”