Hurricanes’ Impact on Health

By Morag MacLachlan, Communications Director for the UNC Institute for Global Health & Infectious Diseases

Matthew, Harvey and Maria. To the residents of eastern North Carolina, Houston and Puerto Rico, these names spark feelings of loss, anxiety and frustration. All three hurricanes made landfall with an intense ferocity, leaving destruction and flooding in their wake. Yet hurricanes leave more than a physical toll behind. These powerful storms impact human health.

“The list of health hazards during and after a hurricane is long,” says David Weber, MD, MPH, professor of medicine, pediatrics and epidemiology at UNC. “And this applies not only to residents, but to volunteers who respond to these areas as well.”

Algal blooms like this one form after major storms. Photo courtesy of Hans Paerl

Algal blooms, like this one, can form after hurricanes.
Photo courtesy of Hans Paerl

A Big Bathtub
In October 2016, Hurricane Matthew struck eastern North Carolina, killing 26 people and causing $4.8 billion in damage. In addition to flooding coastal plains, the storm dropped more than one foot of rain 100 miles inland. Rivers rose to levels not seen since Hurricane Floyd in 1999.

Eastern North Carolina is home to the Pamlico Sound, the nation’s second largest estuarine complex, says Hans Paerl, PhD, the Kenan Professor of Marine and Environmental Sciences, at UNC’s Institute of Marine Sciences in Morehead City, N.C. Listen to the episode of UNC podcast Well Said featuring Paerl discussing hurricanes’ impact on water quality.

“The sound is lagoonal, functioning like a big bathtub collecting water from the nearby rivers,” says Paerl. “Under normal conditions, the sound is ideal for providing nutrients that support the growth of algae, the key food source for nourishing shellfish and finfish.”

Pamlico Sound is home to 90 percent of North Carolina’s commercial finfish and shellfish catches. It sits on the coast and is bounded by the Outer Banks. But during a storm, its confinement by the Outer Banks is actually harmful. The barrier islands limit the sound’s exchange of water with the Atlantic, slowing the removal of the large influx of nutrients and contaminants into the sound from local rivers. The excessive nutrient and contaminant accumulation can cause toxic algal blooms and decrease the amount of oxygen available to fish and bottom-dwelling shellfish in the sound.

If an algal bloom forms, fishing from and swimming in affected waters are discouraged, and if the bloom is toxic, it can constitute a health hazard.

Another factor is the drop in salinity in the sound due to dilution from the huge influx of floodwater following these storms. This can stress commercially- and recreationally-important fish and shellfish species that require specific salinity regimes.

“Some shellfish species, such as oysters and scallops, could not escape the ‘freshening’ of the sound, leading to mass mortality. And in the case of crabs, the fishery was seriously impacted for several years after Hurricane Floyd’s (1999) floodwaters caused a protracted drop in salinity,” Paerl recalls.

Paerl leads a research team that is constantly monitoring the sound, utilizing the N.C. Department of Transportation’s fleet of ferries as monitoring platforms. Each time the ferries cross the Neuse River or Pamlico Sound, water quality data is collected. The program, called FerryMon, sends data to UNC’s Institute of Marine Sciences. The data is then forwarded to state and federal water quality and fisheries management agencies.

“It’s good that we have the ferries as well as other water quality monitoring efforts like the Neuse R. Estuary’s biweekly ModMon program in place testing for water quality because these storms seem to be getting more extreme each year,” Paerl says. “This year we had Harvey, Irma and Maria – all category 5 hurricanes at some point during their transit of the Atlantic Ocean and Gulf of Mexico. That’s never happened before.”

David Weber, MD, MPH, professor of Medicine and Pediatrics, UNC School of Medicine and professor of Epidemiology, UNC Gillings School of Global Public Health

David Weber, MD, MPH, cautions against driving through flooded waters.

Floodwater Dangers
Hurricanes also impact the drinking water supply. Weber advises people to pay close attention to advisories to boil or filter water. This is especially important if local sewage treatment plants are offline as harmful bacteria like E. coli and salmonella can cause nasty gastrointestinal illnesses.

Wading through water to get to safety is another hurricane hazard. If there are downed power lines in the water, there is the risk of electrocution, Weber says. Bacteria in the water is also a danger, especially since it can enter the body through any tiny cuts.

“There are organisms in the water; funny sounding names like vibrio and aeromonas (bacteria) that can cause local, very severe wound infections—a sort of flesh-eating bacteria,” Weber says.

He also cautions people not to drive through flooded areas.

“You may think, ‘Oh this is only waist-deep. If I can walk through it, I can drive through it,’” he says. “But cars don’t float and you can easily become trapped in your automobile.”

Darrell and Teresa Kidd are two UNC employees who responded to eastern North Carolina after Hurricane Matthew.

Darrell and Teresa Kidd are two UNC employees who responded to eastern North Carolina after Hurricane Matthew.

Safely Volunteering
UNC employees Teresa and Darrell Kidd traveled to Lumberton, N.C., after Hurricane Matthew to volunteer with relief efforts. They removed flood-damaged flooring in three homes.

“We saw children’s toys laying there as we worked and that’s when it really hits you that what these people took with them when they fled is all that they have left,” says Teresa Kidd, an accounting technician in the UNC School of Social Work.

She and her husband took several precautions while in Lumberton to remain in tip top shape to volunteer. They drank bottled water and donned face masks to prevent breathing in mold. They also noticed a local church had been transformed into a pharmacy, allowing local residents to access their medications.

“Packing your medications is an important consideration when you travel to a hurricane-hit area to volunteer because you do not know when local pharmacies will be back online,” says Weber. “You should also be up-to-date on all of your vaccinations, especially if you are going to help out at a shelter where there will be large amounts of people and the potential for a respiratory disease, like influenza, is high. And a tetanus shot helps prevent infection if you get a cut from an unclean surface.”

Because hurricanes bring heavy rainfall that spawns standing water and mosquitoes, Weber recommends packing bug repellent as well. Despite all of these potential health risks, the Kidds said they would volunteer again. In fact, Darrell Kidd hopes to spend more time responding to disasters once he retires from his job as a maintenance coordinator for UNC’s Department of Exercise and Sports Science.

“The news covers the highlights of these hurricanes, but you really see the nitty gritty when you volunteer,” he says. “It was incredible to see UNC staff and students working together getting their hands dirty and helping the Lumberton community.”

UNC employees can use community service leave time to volunteer with disaster relief during work hours. Learn more about this HR policy.

The Kidds joined UNC students and staff in pulling up flooded flooring in homes in Lumberton, N.C.

The Kidds joined UNC students and staff in pulling up flooded flooring in homes in Lumberton, N.C.
Photo courtesy of Darrell Kidd

Reducing Risk
As the 2017 hurricane season winds down, experts are sharing ways to minimize the impact of these storms next year.

To minimize the amount of nutrients and contaminants floodwaters discharge into the Pamlico Sound, Paerl suggests:

  • Homeowners refrain from applying lawn fertilizer, herbicides and pesticides near hurricane season;
  • Farms and municipalities add vegetative buffers around lands bordering streams;
  • Cities, industries and shopping centers construct storm water runoff retention ponds; and
  • Businesses surround impervious surfaces, like parking lots, with vegetation.

Princeville is a town in eastern North Carolina that was devastated by Hurricane Matthew in 2016. As part of the rebuilding efforts, the town’s leadership is consulting with risk reduction and disaster recovery experts about possibly moving some of Princeville’s key services, like fire and schools, to a nearby 52-acre parcel outside the 100-year floodplain.

“Homes exposed to floodwaters grow mold and this causes illness, especially among the elderly or people with a compromised immune system,” says Gavin Smith, PhD, who is working with Princeville on rebuilding and who directs the U.S. Department of Homeland Security’s Coastal Resilience Center of Excellence. “Princeville is the first town to be founded by freed slaves. So, we are exploring this site as a way to balance remaining respectful to the town’s history with managing its extreme flood vulnerability.”

Smith, who is also a research professor in the UNC Department of City and Regional Planning, helped lead a five-day Princeville Community Design Workshop. The goal of the workshop included how this 52-acre parcel could be physically, socially, environmentally and economically connected to the existing town of Princeville, as well as other parcels of land adjacent to the town that have yet to be acquired.

The five-day design process involved a team of more than 40 volunteer architects, land use planners, landscape architects and civil engineers as well as more than 60 historians, floodplain management officials, economic development experts and other professionals meant to provide key contextual information to the design team. One of the elements of this effort that made it so unique was the direct involvement of the North Carolina Division of Emergency Management throughout the process to include the formulation of the workshop approach, publicizing the event, and leading logistics and operations support during the event.

Residents and town officials were closely involved in the drafting of design and community development options during the week-long process. Emphasis was placed on flood resilience, social and community cohesion, equity, history and culture, quality of life, and other key aims identified by the community. The resulting designs were provided to the Town of Princeville and state officials upon completion of the workshop. This information will serve as a bridge to the larger, long-term disaster recovery plan to be developed over several months following the workshop, as well as a roadmap used to develop the 52-acre site.

“It was apparent that the success of the event was based on combining the logistics and operations-based strengths of emergency management with the strengths of a hand-picked set of design and planning experts drawn from around the country,” Smith says. “This provides what is believed to be a best practice that could be used in other post-disaster settings.”