The term “natural” can hardly be used to refer to disasters anymore. “When threats hit a community and cause destruction, it is assumed that people have done something wrong, such as deforestation, (or) building in a riverbed or on a very steep slope,” explains meteorologist Marcelo Seluchi.

Seluchi heads the operational and modeling sector of the Center for Monitoring and Early Warning of Natural Disasters (Cemaden), a federal agency based in São Paulo, Brazil. The center is responsible for observing vulnerable areas in about a fifth of the country’s 5,568 municipalities, where landslides and floods have the greatest impact. Nine out of every 100 Brazilians live in these risk areas.

In recent decades, urbanization in Brazil has been largely unplanned and chaotic. According to the Brazilian Institute of Geography and Statistics, 84% of the population lives in cities and urban areas. “Nobody goes to live in a risky area because they want to or because they are stupid,” says Raquel Rolnik, an urbanist at the University of São Paulo. “They are workers whose income does not allow them to buy or rent a home in a suitable location.”

Larger populations living in high-exposure areas and more frequent extreme weather events are causing disasters. Science has shown that global warming has increased evaporation, adding more water vapor to the air, leading to more intense precipitation and unpredictable storms. This is making landslides even more common in Brazil’s Atlantic Forest, including the Serra do Mar mountains, which stretch 930 miles along the country’s coastline and rise to 7,700 feet.

The rocks that make up these mountains are covered with a thin layer of soil and vegetation, with a natural tendency to slide, explains Fábio Augusto Reis Gomes, a geologist at the University of the State of São Paulo. “Heavy rainfall causes water to infiltrate this soil, making it liquid.” This liquid debris flows quickly down these steep slopes, some of which are steeper than 25 degrees.

That’s exactly what happened on February 16, 2023, when record-breaking rainfall hit the coast of São Paulo in southeastern Brazil. That day, Cemaden predicted heavy rains and reported the dangers to local authorities twice. On Saturday night, municipalities received more specific warnings to activate their emergency plans after reaching the maximum risk level by midnight, Cemaden said.

However, different local communities responded differently to the information, and the varying outcomes highlight what is at stake for communities in future disasters.

Effective warning systems

While Cemaden’s forecasts called for 7.8 inches of rain, the cities of Bertioga and São Sebastião received more than three times that amount. Bertioga received 26.8 inches of rain in just one day — the highest amount ever recorded by a rain gauge in Brazil (not counting unmonitored areas). Because the city of Bertioga, with a population of 65,000, is relatively flat and has no homes in the hills, it was not particularly vulnerable. “The largest rainfall in history occurred there, but without any problems in terms of casualties,” Seluchi says.

The story was different 20 miles to the east, in the city of São Sebastião, population 90,000. Here, rain gauges recorded 24.6 inches of rain in the early hours of Sunday morning. Storms followed by landslides ripped through a working-class housing estate on the slopes of Serra do Mar called Vila do Sahy, killing 64 people. These homes were built in the 1980s by poor families looking for work in the nearby beachside hotspot of Barra do Sahy, where wealthy families from big cities flock for the sea-view hotels and well-appointed, multimillion-dollar homes.

Despite their differences, Barra and Vila are closely connected. The only physical barrier between them is a single road. However, the precarious housing conditions in the at-risk area concentrated all the victims on the poorest side of the road, while on the other side a few wealthy people hired helicopters to escape the devastation.

The city of São Sebastião did not issue any statement to inform the public about the storms, which occurred in the days leading up to Carnival — one of Brazil’s most important holidays for tourism. Preparations for the festivities were already in full swing. The city normally receives 500,000 visitors during Carnival weekend, so ordering an evacuation would have meant losing the potential income from these tourists. Instead, lives were lost.

Twenty miles west of Bertioga, the city of Guarujá, population 322,000, suffered only infrastructure damage and no injuries from the storms, despite more than 7,000 families living on hillsides and in stilt houses. The city recorded its highest rainfall in 70 years: about 16 inches. The municipality avoided fatalities by heeding warnings and not underestimating the destructive potential of the conditions—a lesson learned after landslides and flooding in 2020 left 34 people dead.

When the 2023 storm hit, people in high-risk areas left their homes before the rain hit. The Civil Defense informed the population through social media, text messages and on-site visits. (This is similar to the United States Federal Emergency Management Agency, FEMA, but in Brazil, municipalities and states also have their own Civil Defense offices.)

“Teams went to geological risk areas on Friday and Saturday to inform them of the measures to take in case of heavy rainfall, and community leaders have reinforced the alert,” according to an email from the Guarujá City Hall press office.

However, an effective disaster prevention plan must go beyond just warning.

Convincing people to take action

Across Brazil, only 17% of municipalities have warning systems to inform residents of potential risk situations associated with heavy rains. According to Reis, who is also director of the Brazilian Federation of Geologists, some communities only have sirens, which is not enough. “Audio warnings are the last step in the line, because when (a major storm) hits, many people don’t know what to do,” he says. “For that, it’s necessary to do training and simulations, mapping escape routes and shelters.”

Without a flight plan, evacuation warnings are of little use. That’s why Guarujá Civil Defense’s ongoing work includes daily inspections of risky areas, climate monitoring, a geotechnical data platform, and lectures in schools alongside simulations. “Cities are dynamic and risk areas change over the years, so maps need to be updated and the population needs to be informed of these changes during training,” Reis says.

The Brazilian Federation of Geologists highlights the problematic ways in which high-risk areas are often low priorities for governments. “Disasters do not occur due to a lack of technical knowledge, but usually due to negligence on the part of local, state and federal governments. (The) risk management field has well-known mechanisms and tools; when applied in time, they result in success,” reads a statement released to authorities and civil society on February 24.

Many deaths could be prevented if, for example, safe, long-term housing were available and affordable for everyone.

One of the most important aspects of any safety plan is to convince the population of the danger. Even when people have the necessary information, some still refuse to leave their homes, fearing that their belongings will be looted, or they simply distrust the warning.

“Some residents say, ‘I’ve lived here for 40, 50 years and there’s never been a disaster,'” Seluchi says. “That’s a big mistake, because things are happening now that have never happened before: Rain that used to occur every 50 years is now happening every five to 10 years.”

Solutions at the source

In the face of an increasingly threatening climate future, some communities have found ways to raise awareness and prevent fatalities. Sítio Conceiçãozinha is a centuries-old neighborhood on the Guarujá estuary, where some of the community’s 6,000 residents live in homes built on stilts. Flooding was a problem for decades until the local community center launched an environmental project in 2020.

The project focused primarily on cleaning up street litter and found that reducing the amount of trash that goes into drains can also prevent flooding. The project offers educational programs for families and cleanup services. The cleanup works like a credit market: for every kilo of recyclables, such as plastic bottles, someone earns tickets that can then be exchanged for donated food baskets. Each month, the community collects over a ton of recycled materials.

“Recently, Guarujá has been flooded by heavy rains, but not here,” says Cristiane Santos de Lima, one of the women leading the project. “The streets don’t flood anymore because you can’t find bottles to cover the drains, which blocks the water flow.” – Rappler.com

This story was originally published in Yes! Magazine (US) and is being republished in the Human Journalism Network program, supported by the ICFJ, International Centre for Journalists.