麻豆社事件

The term 鈥渘atural鈥� can hardly be used to refer to disasters anymore. 鈥淲hen threats strike a community and wreak havoc, it is assumed people did something wrong, such as deforestation, [or] building in a river channel or on a very steep slope,鈥� explains meteorologist Marcelo Seluchi.

Seluchi runs the operation and modeling sector of the Center for Monitoring and Early Warning of Natural Disasters (Cemaden), a federal agency based in S茫o Paulo, Brazil. The center is in charge of observing vulnerable areas in about one-fifth of the country鈥檚 5,568 municipalities in which landslides and floods have the most impact. live in these high-risk zones.

Over the past decades, urbanization in Brazil has been largely unplanned and taken place at a chaotic pace. now live in cities and urban areas, according to the Brazilian Institute of Geography and Statistics. 鈥淣obody is going to live in a risky area because they want to or because they are stupid,鈥� says Raquel Rolnik, an urbanist from the University of S茫o Paulo. 鈥淭hey are workers whose income does not allow for the purchase or rent of housing in a suitable location.鈥�

Larger populations living in high-exposure areas, combined with more frequent extreme weather events, trigger disasters. that global warming has boosted evaporation, adding more water vapor to the air, which causes more intense precipitation and unpredictable storms. This makes landslides even more common in Brazil鈥檚 Atlantic Forest, including the Serra do Mar mountains, which extend for 930 miles along the country鈥檚 coastline and reach up to 7,700 feet in elevation.

The rocks that comprise these mountains are covered by a thin layer of soil and vegetation, with a natural tendency to slide, explains F谩bio Augusto Reis Gomes, a geologist at S茫o Paulo State University. 鈥淗eavy rains make water infiltrate this soil, turning solid into liquid.鈥� On these steep slopes, some greater than 25 degrees, this liquid debris flows quickly downhill.

That鈥檚 just what happened on Thursday, February 16, 2023, when record-setting rains hit the S茫o Paulo coast in southeast Brazil. That day, Cemaden predicted a heavy rainfall and reported the dangers twice to local authorities. On Saturday night, municipalities received more specific alerts to put their contingency plans in place, having reached the maximum level of risk by midnight, according to Cemaden.

But various local municipalities responded differently to the information, and the resulting range of outcomes shows what鈥檚 at stake for communities in future disasters. 

Effective Warning Systems

While Cemaden鈥檚 forecasts predicted 7.8 inches of rain, the cities of Bertioga and S茫o Sebasti茫o received more than triple that amount. In Bertioga, 26.8 inches of rain fell in just one day鈥攖he highest amount ever recorded by a rain gauge in Brazil (not counting unmonitored areas). Since the city of Bertioga, population 65,000, is relatively flat and doesn鈥檛 have residences built in the hills, it was not particularly vulnerable. 鈥淭he biggest rain in history occurred there, but with no problems in terms of causing victims,鈥� Seluchi says.

The story was different 20 miles east, in the city of S茫o Sebasti茫o, population 90,000. Here in the early hours of Sunday morning, rain gauges recorded 24.6 inches of rain. Storms followed by landslides swept through a working-class complex 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 jobs in the nearby beachside hot spot of Barra do Sahy, where wealthy families from big cities come for the sea-view hotels and well-equipped houses costing millions of dollars.

Despite their differences, these two worlds鈥擝arra and Vila鈥攁re closely linked. The only physical barrier between them is a single road. However, precarious housing conditions in the high-risk area ended up concentrating all the victims on the road鈥檚 poorest side, while on the opposite side, some moneyed people went so far as to hire helicopters to escape the devastation.

The city of S茫o Sebasti茫o did not release a single statement informing the public about the storms, which came in the days leading up to Carnival鈥攐ne of the most important holidays for tourism in Brazil. Preparations for the festivities were already in full swing. Normally the city receives 500,000 visitors on Carnival weekend, so ordering an evacuation would have meant losing the income potential from these tourists. Instead, lives were lost.

Twenty miles west of Bertioga, the city of Guaruj谩, population 322,000, had only infrastructure damage and no injuries in the storms, despite having more than 7,000 families living on slopes and in stilt houses. The city recorded the highest volume of rain in the past 70 years: around 16 inches. The municipality managed to avoid fatalities by listening to the warnings and not underestimating the conditions鈥� destructive potential鈥攁 lesson learned after experiencing landslides and floods in 2020 that left 34 dead.

When the 2023 storm hit, people from high-risk areas left their homes before getting impacted by the rain. The population was notified via social media, SMS, and on-site visits by the Civil Defense. (This is comparable to the United States Federal Emergency Management Agency, , but in Brazil, municipalities and states have their own Civil Defense offices too.) 鈥淭eams went to areas of geological risk on Friday and Saturday informing [them of ] the measures to be adopted in case of heavy rain, and community leaders reinforced the alert,鈥� according to an email from the City Hall of Guaruj谩鈥檚 press office.

However, an effective disaster prevention plan has to go beyond warnings.

Convincing People to Act

Across Brazil, to inform residents about possible risky situations associated with heavy rains. Some communities only have sirens, which isn鈥檛 enough, according to Reis, who is also a director of the Brazilian Federation of Geologists. 鈥淪ound alerts are the last step in the line, because when [a major storm] hits, many people don鈥檛 know what to do,鈥� he says. 鈥淏efore that, it is necessary to do training and simulations, mapping escape routes and shelter points.鈥�

Without an escape plan, evacuation warnings don鈥檛 do much good. That鈥檚 why Guaruj谩 Civil Defense鈥檚 ongoing work includes daily inspections in high-risk areas, climate monitoring, a geotechnical data platform, and lectures given in schools alongside simulations. 鈥淐ities are dynamic, and risk areas change over the years, so the mapping must be updated and the population informed about these changes during the training,鈥� Reis says.

The Brazilian Federation of Geologists highlights the problematic ways in which high-risk areas are often a low priority for administrations. 鈥淒isasters do not occur due to lack of technical knowledge, but mostly by negligence of local, state, and federal administrations. [The] risk management field has well-known mechanisms and tools and, whenever applied in time, they result in success,鈥� reads a released on February 24 to authorities and civil society.

Many deaths could be avoided if, for example, safe long-term housing was 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 for fear of their belongings being looted, or they simply distrust the warning. 鈥淪ome residents say, 鈥業鈥檝e lived here for 40, 50 years and [no] disaster has ever happened,鈥欌�� Seluchi says. 鈥淭his is a big mistake, because today things that have never happened are happening now鈥攔ain with a frequency of every 50 years now occurs every five to 10 years.鈥�

Solutions at the Source

In the face of an evermore-threatening climate future, some communities have found their own means of raising awareness and preventing fatalities. S铆tio Concei莽茫ozinha is a century-old neighborhood on the Guaruj谩 estuary where some of the community鈥檚 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.

Primarily aimed at cleaning up street pollution, the project found that it could also avoid floods by reducing the garbage backing up storm drains. The project offers educational programs for families as well as janitorial services. And the cleanup works as a credit market: For each collected kilogram of recyclable material, such as plastic bottles, a person earns tickets that can then be exchanged for donated food baskets. Every month, more than a ton of recycled material is collected by the community.

鈥淩ecently, heavy rains have filled Guaruj谩 up, but not here,鈥� says Cristiane Santos de Lima, one of the women heading the project. 鈥淭he streets don鈥檛 flood anymore because you can鈥檛 find bottles covering the drains, obstructing the water evasion.鈥�