Floods in Rio Grande do Sul

Floods in Rio Grande do Sul were a large-scale natural disaster that began on April 29, 2024, in southern Brazil, caused, among other reasons, by climate change. The repercussions are still unfolding.

Authorship: Marielle Franco Favela Dictionary Team.

About

Floods in Rio Grande do Sul were a large-scale natural disaster that began on April 29, 2024, in southern Brazil, caused by climate change. Its repercussions are still ongoing. So far, the event has resulted in 100 fatalities, 372 injured, 128 missing, over 160,000 displaced individuals, and impacted 1.4 million people in at least 417 of the state’s 497 municipalities^[1].

The episode affected all regions of the state, leaving entire cities and neighborhoods submerged. The floods and landslides damaged approximately 150 segments of federal and state highways^[2], caused the collapse of bridges, breaches in dams, the closure of the state’s main airport, and disruptions in water, electricity, fuel, and basic supply distribution in the affected areas. Services related to health and education were also interrupted, and shortages of supermarket products worsened the crisis caused by the disaster.

Homes and businesses in evacuation zones suffered a wave of looting, creating a sense of insecurity and complicating the evacuation of people from at-risk areas. This led to the hiring of temporary police officers and the deployment of National Force troops to Rio Grande do Sul^[3].

A task force was established to tackle the flooding, involving hydrologists, meteorologists, civil defense teams, firefighters, civil, military, and highway police (including personnel from other states), lifeguards, the Air Force, Navy, Army, doctors, nurses, psychologists, and thousands of volunteers.

According to the National Confederation of Municipalities (CNM), the economic damages caused by the floods have already reached R$4.6 billion, affecting both private and public sectors^[4]. This prompted municipal, state, and federal governments to swiftly allocate extraordinary resources to address the crisis.

In response, the federal government announced an emergency package of R$1.06 billion^[5], funding for rebuilding homes^[6], R$2.9 billion in FGTS fund withdrawals, and expanded unemployment insurance and salary bonuses for those affected^[7]. The government also suspended the state’s debt payments to the Union during the state of emergency^[8]. The Rio Grande do Sul state government allocated an additional R$200 million in emergency aid^[9] and announced a new phase of the "Volta por Cima" program, created in 2023 to assist families affected by climatic events.^[10]

This disaster is considered the worst flood-related tragedy in the country’s history, bringing climate emergency issues to the forefront and highlighting a series of allegations regarding the lack of programs and resources for climate and environmental prevention, as well as governmental neglect of these issues.

Causes

Various factors help explain the catastrophe and its scale in Rio Grande do Sul, ranging from meteorological phenomena to the region’s geography, urban development patterns, human-induced climate change, and failures in flood containment systems.

Meteorologists summarize the floods in Rio Grande do Sul as the result of three converging factors: the presence of strong wind currents in the region, a moisture flow from the Amazon, and a central heat wave in the country. Strong winds destabilize weather systems, the northern moisture increases rainfall intensity, and the central heat wave prevents the cold front from moving away from the southern region. Additionally, the El Niño phenomenon warms ocean waters, further increasing instability^[11].

The intense humidity and strong winds, combined with the atmospheric blockage caused by the central heat wave, explain the approximately 1,000 millimeters of rainfall recorded in the state—equivalent to six months’ worth of rain in the region. However, other factors contribute to the high number of affected people, particularly urban development and land use patterns.

According to Rualdo Menegat, a geologist and professor at the Federal University of Rio Grande do Sul (UFRGS):

"The cities' master plans were dismantled to promote real estate speculation. In Porto Alegre, for instance, the entire central area now flooded at the port was offered for privatization and the construction of high-rise buildings. Our protection systems were neglected, as if floods would never occur again."

The deforestation of native vegetation for real estate purposes also hampers rainwater drainage.

"There is intensive land occupation. In Porto Alegre, particularly along the Guaíba River in the southern zone, we still have an ecosystem somewhat resembling its past state, with wetlands, forests, and hills. But these areas are under pressure from real estate speculation. Due to policies promoting intensive urban land use, these areas are being exposed, sacrificing the last environmental reserves that regulate water flow," explains Menegat^[12].

The urbanization of “flood plains” and the region’s geographic features also contribute to the disaster. Many affected cities, such as Porto Alegre, are located on low-lying terrain. Moreover, the Guaíba River—an interconnected system of lake and river—receives water from the large Jacuí River basin, the hardest-hit area. The basin's waterflow was obstructed near Porto Alegre due to strong winds opposing the river’s natural course, exacerbating the flooding^[13].

Another significant factor is human-driven climate change. The abnormal intensity of the floods is directly linked to these changes, as explained by Paulo Artaxo, a physicist and professor at the University of São Paulo (USP):

"There is no doubt that the increase in floods and torrential rains is definitively associated with climate change and the acceleration of these changes across our planet," Artaxo stated in a Ministry of Science, Technology, and Innovation (MCTI) release.

Artaxo emphasizes that events in Rio Grande do Sul should not be viewed in isolation but as part of a global trend. In recent months, unprecedented rainfall has also caused problems in Dubai (United Arab Emirates) and China. Conversely, historic droughts, such as the one that affected the Amazon at the end of last year, are becoming more common.

The principle is straightforward: as human-driven climate change intensifies—mainly due to greenhouse gas (GHG) emissions—extreme weather events are becoming more frequent. This is also one of the conclusions of the Intergovernmental Panel on Climate Change (IPCC), a document designed to guide public policy development in Brazil^[14].

Chronology of Events

The aftermath of the floods in Rio Grande do Sul and the resulting crisis remain ongoing. Below is a timeline of key developments during the first 30 days of the tragedy, as compiled by the G1 news portal^[15].

Saturday, April 27: Initial Storm

On April 27, prior to the onset of the disaster, municipalities in the Vale do Rio Pardo region experienced heavy rain and hail. Santa Cruz do Sul was one of the hardest-hit areas.

Sunday, April 28: Early Impacts

The Civil Defense recorded damage in 15 municipalities following the storm. The National Institute of Meteorology (Inmet) issued an orange alert for storm risks across the southern half of the state.

Monday, April 29: Intensified Forecast

By the end of the day, Inmet predicted heavy rainfall for the state’s southern region, marking the beginning of the tragedy.

Tuesday, April 30: First Deaths

Rio Grande do Sul reported its first fatalities from the storms. Two men in a car were swept away by floodwaters in Paverama, raising the death toll to eight.

Roads were blocked in several areas.
A bridge in Santa Tereza was swept away during a recorded warning by the mayor about the storm.
Another bridge collapsed in Santa Maria, severing a critical link on RSC-287 between the central region and Porto Alegre's metropolitan area. The military began building a temporary crossing.

Wednesday, May 1: Woman Swept Away by Currents

A video captured a woman being swept away by floodwaters in Candelária. She was later found alive and recounted her ordeal.

Governor Eduardo Leite acknowledged challenges in rescue efforts:

"We won’t be able to rescue everyone."

The Civil Defense issued urgent evacuation orders for residents in the Vale do Taquari region.

Thursday, May 2: Historic Flooding

The Taquari River exceeded 30 meters in height, its highest recorded level.
A partial dam breach occurred between Cotiporã and Bento Gonçalves.
In Porto Alegre, the Guaíba River surpassed the flood threshold at 3.63 meters.
President Lula and Governor Leite discussed response measures, with Lula promising funding and coordinated action.

Friday, May 3: Chaos in Porto Alegre

The death toll rose to 39 as flooding intensified in Porto Alegre.

Both Guaíba bridges were closed due to rising water levels and damage after two vessels collided with the newer bridge.
The Guaíba River reached 4.77 meters, surpassing the 1941 record.
Salgado Filho International Airport was shut down.
Rescuers searched for 34 people trapped in a landslide near Veranópolis and Bento Gonçalves.

Saturday, May 4: Deadliest Disaster in State History

With 55 confirmed deaths, this tragedy surpassed the 2023 Vale do Taquari disaster.

The Guaíba River reached 5 meters, flooding Porto Alegre’s bus terminal and surrounding areas.
Entire neighborhoods in the metropolitan region, including Canoas and Eldorado do Sul, were submerged.

Sunday, May 5: Record-Breaking Guaíba Levels

The Guaíba River rose to 5.33 meters, the highest level in recorded history.

President Lula, alongside other national leaders, surveyed the affected areas by helicopter.

Monday, May 6: Flooding Hits City Center

Mayor Sebastião Melo advised residents of Cidade Baixa and Menino Deus to evacuate after rising waters compromised electrical safety.

Wednesday, May 8: Floodwaters Reach Southern Region

After devastating the Serra, Vales, and metropolitan areas, the flooding reached the southern regions of the state. Cities like São José do Norte, Pelotas, and Rio Grande declared maximum alert, with thousands forced to evacuate.

Thursday, May 9: Rescue of Caramelo the Horse

During an aerial survey of Canoas, a news crew from RBS TV spotted a horse stranded on the roof of a house in the Mathias Velho neighborhood. Named Caramelo, the animal’s plight touched hearts across Brazil, prompting public officials to organize a rescue mission. Caramelo was rescued on May 9 and is now recovering at the University Hospital of the Lutheran University of Brazil (Ulbra) in Canoas.

Wednesday, May 15: Water Recedes in Vale do Taquari

In Vale do Taquari, residents were met with destruction and mud for the second time since the storms began. The Taquari River level dropped to 18.75 meters, below the flood mark of 19 meters, revealing the devastation left behind. Previously, the river had peaked at 33 meters.

Residents like Irno Gisch, a local broadcaster, started cleaning their homes and belongings:

"Many families lost their homes. We were fortunate to still have ours, allowing us to clean and return to normal life."

Thursday, May 16: Water Recedes in Porto Alegre

As the Guaíba River receded, Porto Alegre residents began dealing with the aftermath. Dead animals, exposed sewage, and the stench of decay filled streets in neighborhoods like Menino Deus, Cidade Baixa, and the Historic Center.

Sunday, May 19: Looting

While the floods inspired acts of solidarity across Brazil, they also exposed vulnerabilities in public security. The state police arrested 130 individuals in connection with crimes during the floods.

Of these, 48 were for property crimes like theft from flood victims.
Another 49 were detained in shelters, though details were not disclosed.

Monday, May 20: First Death from Leptospirosis

A 67-year-old man died of leptospirosis in Travesseiro, a town affected by the floods in Vale do Taquari. This was the first fatality linked to the disease during the disaster. The state reported three more deaths and over 1,000 suspected cases of leptospirosis in May.

Friday, May 29: One Month Since the Disaster

One month after the catastrophe, Rio Grande do Sul was still grappling with its recovery. Federal and state governments introduced support measures, including:

Wage bonuses,
Auxílio Reconstrução payments,
Calamity Withdrawals from FGTS, and
Advance refunds on personal income tax (IRPF).

Provisional cities were proposed for displaced residents, while many remained in temporary shelters or with friends and family. Rivers and lakes were still swollen, but researchers indicated that conditions could normalize within 30 days if dry weather persisted.

Solidarity in the Face of Disaster

The floods in Rio Grande do Sul inspired a nationwide outpouring of solidarity, with countless individuals and organizations mobilizing to provide relief and support to affected communities. Efforts included:

Volunteer Enrollment: Over 15,000 people from across Brazil registered for emergency volunteer activities coordinated by municipal and state agencies^[16].
Financial Contributions: Donations poured in through PIX and bank deposits, demonstrating the generosity of the Brazilian public.
Material Aid: Massive quantities of food, water, medical supplies, clothing, and other essentials were distributed. Many also offered temporary shelters for displaced families.

While precise totals for all donations across various organizations are unavailable, the state government revealed that its official fundraising initiative, SOS Rio Grande do Sul, collected over R$100 million^[17].

At the height of the disaster, 839 temporary shelters were established to house those displaced by the floods, reflecting a remarkable effort to provide safety and comfort to victims during their time of need.

This collective response highlights the resilience and compassion of Brazilian society in addressing one of the nation’s most significant environmental crises^[18].

Complaints

During the catastrophe, various types of complaints were made, either to hold authorities accountable for the events or to report the insecurity generated by the crisis that devastated the state of Rio Grande do Sul.

In some areas of Porto Alegre and cities in the metropolitan region evacuated by municipal and state authorities due to the floods, there were reports of looting and invasions of homes and commercial establishments. On May 6, 10 individuals were arrested by the Military Police for looting evacuated establishments^[19]. On that occasion, there were attempts to lynch the suspects, who had to be escorted by security forces to avoid further violence.

Reports of theft, harassment, and sexual violence were also registered in temporary shelters for flood victims. In these cases, the Public Security Secretariat stated that at least 11 people were arrested for committing these crimes^[20].

These incidents created a general sense of insecurity in the cities, complicating rescue efforts and crisis management. To mitigate the situation, the state government announced the mobilization of 1,000 retired military police officers through the More Effective Program^[21], as well as the deployment of Federal Forces by the federal government.

Another series of complaints, still ongoing, focuses on holding authorities and relevant agencies accountable for the prevention and mitigation of damages caused by the disaster. Environmental, community, and housing movements—along with some lawmakers—denounced the lack of maintenance by the Porto Alegre municipal government of the city’s pump stations, which are part of its flood control system.

According to a group of experts, the system failed due to a lack of maintenance of the sluice gates and the precarious operation of some pump stations, which were either flooded or stopped functioning due to power outages in the areas where they are located. As a result, the flooding reached areas that were supposed to be protected by the city’s system^[22]. A formal complaint regarding this negligence was filed with the Public Prosecutor's Office by State Representative Matheus Gomes (PSOL/RS)^[23].

Criticism has also been directed at Governor Eduardo Leite for amending 480 provisions of the Environmental Code of Rio Grande do Sul. According to environmental protection organizations, these regulatory changes have loosened state legislation, allowing for greater harm to environmentally protected areas^[24].

Impacts and Economic Packages

According to the state government, at least R$19 billion in resources will be needed for the reconstruction of Rio Grande do Sul. This amount refers to the costs required for the construction of new housing, repairs to damaged roads and bridges, the construction of completely destroyed roads during the floods, and other infrastructure equipment^[25].

In addition to the direct impacts, the Federation of Industries of the State of Rio Grande do Sul (Fiergs) estimates that 94.3% of all state economic activity has been affected. Considering only the metropolitan regions of Porto Alegre, Vale dos Sinos, and Serra, the losses amount to approximately R$220 billion^[26].

In agriculture and livestock, the losses caused by the floods may lead to a 3.5% decline in the national GDP in this sector, as the state accounts for at least 12% of the national wealth. The biggest impact occurred in rice production, where the state is the largest producer in the country^[27].

All these indicators are still being analyzed by municipal, state, and national governments to assess the losses and economic impacts of the disaster. However, some measures have already been announced, such as the federal government’s R$51 billion package. This package includes the advance of benefits (such as Bolsa Família, gas assistance, among others), additional payments of unemployment insurance installments to the affected, and the opening of credit for the reconstruction of housing and businesses^[28].

Other measures will still be taken to strengthen the economic recovery of Rio Grande do Sul.