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How do extreme weather events and disasters affect communities long term? Solomon Hsiang discusses the impacts on economic growth and health, and how research can improve emergency management and mitigation strategies.

The immediate effects of hurricanes and severe storms are devastating and plain to see: flooded roads, destroyed homes, displaced people, lost loved ones, and grieving families. During heat waves, emergency departments see more patients with heat illness and kidney injury.

New research shows these initial impacts from extreme weather events are only the beginning of a cascade of consequences for human health and the economy.

Solomon Hsiang, a professor of environmental social sciences in the Stanford Doerr School of Sustainability, has been applying data science methods to reveal these long-term ripple effects and inform decisions about how to mitigate them. By combing through hundreds or thousands of extreme events and comparing their timing to changes in measures of public health and economic activity, he and colleagues can see which impacts happen time and again after a tropical cyclone or heat wave.

"It's really important to look at lots of data," he said. "That helps you determine that this is not just coincidence."

Here are four essential facts from his research about extreme weather and disaster relief.

Extreme storms can slow economic growth for decades.

Some economists have speculated that after the initial shock of a powerful storm, the affected region's economy will rebound quickly. Some have even suggested that hurricanes cause "creative destruction," leading to a boom in productivity in their aftermath.

Evidence suggests a bleaker reality. In 2014, Hsiang and colleagues reported that after countries experience tropical cyclones, it takes them 20 years on average to . The analysis was based on records for 6,712 storms between 1950 and 2008, comparing national economic data before and after a storm hit. The average cyclone lowers per capita income by 3.6%, akin to a currency crisis, and the most extreme storms send per capita incomes into a "nosedive," Hsiang said.

"Continuing to support and invest in communities for a long time after disaster strikes is probably necessary to get them back to where they were," he said.

"Hurricane," "cyclone," and "typhoon" are regional names for tropical storms with wind speeds of at least 119 kilometers (74 miles) per hour. "Tropical cyclone" is the generic term for these powerful rotating storms.

Other climate impacts slow economic growth, too. In another analysis, Hsiang found that every weekday over 86 degrees Fahrenheit .

Deadly effects from hurricanes and heat waves linger for years.

On average, each hurricane or tropical storm that hits the U.S. kills about 24 people directly, by drowning in flood waters, for example. In 2024, a study by Hsiang and postdoctoral scholar Rachel Young showed that these deaths were just the beginning of a long tail of early deaths set in motion by storms.

The two scientists analyzed tropical cyclone data and mortality rates between 1930 and 2015, studying the spikes in mortality that occurred after 501 storms. The average storm after it hit, leading to the early deaths of more than 7,000 to 11,000 people. Infants and the Black population experienced especially high rates of increased mortality following the cyclones.

Extreme heat also causes indirect early deaths. In a 2018 study, Hsiang and colleagues including Stanford's Marshall Burke and Sam Heft-Neal reported that after periods of above-average heat. They estimated that unmitigated climate warming could lead to up to 40,000 additional suicides by 2050. "You see very similar patterns around the world," added Hsiang.

Financial strain from disasters may contribute to long-term health impacts.

Researchers cannot yet pinpoint the precise series of events that might lead someone to die early after a hurricane. It may be that a hurricane causes costly water damage to a home, leading to the owner dipping into their retirement savings. That loss in savings then has a ripple effect, which may ultimately affect access to health care.

The team is working to test hypotheses such as this, which may lead to policies designed to help. Credit score and savings data, for example, can indicate how people are coping financially in the months and years after a storm. If such an analysis uncovers that people are spending their retirement savings to rebuild their homes, researchers could then test whether relief payments to retirees reduce the incidence of early deaths.

"Once we have a pretty clear picture of what's going on," he said, "then you can do a big experiment to see if we give them some cash or free medical help, do we start seeing people live longer."

Public disaster relief programs can save lives and money.

Public funds dedicated to disaster relief can help reduce economic damage from extreme weather events, Hsiang said. For example, a 2024 study found disaster loans granted by the U.S. Small Business Administration after natural disasters. He added that state-backed insurance coverage, such as , can also provide relief funds for extreme events. Such resources will become even more important as climate change increases the intensity of storms, heat waves, and droughts. "We have a bunch of tools that people have shown work," he said.

Public programs that help people in flood-prone areas get out of harm's way before the next severe storm strikes can also be cost-effective in the long run. Preliminary findings by Young suggest FEMA's home buyout program, where the agency buys homes that have been damaged repeatedly by storms, does not cost taxpayers more money than traditional disaster relief.

Similarly, in California may reduce the costs of wildfires over time. "That's the kind of thing you would want to scale up," Hsiang said. "We should find a way to streamline it, make it more efficient, drive down those costs, and drive up the benefits."