A man and a woman wade through floodwaters next to a house painted orange and yellow, with other structures visible in the distance.

Floods: Facts, FAQs, and how to help

As one of the deadliest natural disasters, floods inundate communities, demolish homes, and disrupt livelihoods all around the world. In 2024, floods have ravaged regions in Afghanistan, Brazil, Sudan , and several countries in East Africa, with scenes of devastation also reported in  Europe and the United States . These catastrophic events have claimed numerous lives, escalated the suffering of the affected communities, and heightened the risk of waterborne diseases like cholera .

Explore flood-affected regions worldwide, discover key facts about the causes and effects of floods, and find ways to support survivors worldwide.

Floods: Facts, FAQs, and how to help

Fast facts: Floods

  • Floods are a significant global hazard, with an estimated 1.47 billion people worldwide (19% of the population) facing intense flooding risk , including nearly 600 million people living in poverty, according to a 2020 World Bank analysis.
  • East Asia and South Asia are particularly vulnerable to flood waters, with approximately 1.36 billion people exposed to flooding in densely populated, high-risk areas like coastal regions and low-lying river plains.
  • Floods are a widespread natural disaster in the US as well, where approximately 75% of all presidentially declared natural disasters involve flooding . All 50 states can experience flash floods.
  • In 2023, the US experienced four significant flooding events, including devastation in California , Florida (a 1-in-1,000-year rainfall event), and the eastern and northeastern regions .
  • Flash floods have the power to carry away cars, uproot trees, and demolish buildings and bridges.
  • As little as 6 inches of moving water can knock a person down, and 2 feet of moving water can sweep a vehicle away.
  • Floods can cause serious health problems , including diseases like cholera and typhoid, injuries from cleanup efforts, and exposure to harmful chemicals.

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People with backpacks wade through knee-high water on a flooded city street.
A scene of devastation in downtown Porto Alegre, capital of Rio Grande do Sul, Brazil, after massive flooding on May 4, 2024. (© 2024 photo courtesy of Marcelo Liotti Jr.)

What is the definition of a flood?

A flood occurs when water overflows onto normally dry land, whether from rising waters in rivers, streams, or drainage ditches, or from heavy rainfall collecting in one area. Unlike flash floods, which happen suddenly and last for a short time, flooding can last for days or even weeks, causing prolonged disruption and damage to affected communities.

Communities at greater risk for flooding include those in low-lying areas, near bodies of water, or downstream from dams.

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What causes floods?

Heavy rainfall over days or in short, intense bursts are the leading causes of floods. Flooding can also result from debris jams or dam failures. Severe thunderstorms, tropical cyclones, and urbanization also contribute to flooding.

The most dangerous kind of flood is the flash flood, which can occur within six hours of a rain event or dam failure. Various factors, such as rainfall intensity, topography, soil conditions, and ground cover, influence flooding, whether it develops slowly or quickly.

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Where is flooding happening right now?

Afghanistan

Since May 10, 2024, Afghanistan has faced severe flooding across the nation, causing hundreds of fatalities and impacting over 500,000 people, with many losing their homes, livestock, and livelihoods. Following a dry winter, the unusually heavy May rainfall caused massive flooding as the hard ground couldn’t absorb the water. Warm temperatures also melted mountain snow, leading to overflowing rivers and inundating villages with mud. The floods are worsening food insecurity in an already hunger-stricken country.

Aerial view of the landscape with structures covered in mud waters following a flood.
Unusually heavy May rain has caused severe flooding across Afghanistan, leading to numerous deaths and extensive damage to property, livestock, and crops. More than 500,000 people have been affected, with significant consequences in the provinces of Badghis (pictured above), Ghor, Herat, and Faryab. (© 2024 World Vision staff)

Brazil

In Brazil, torrential rains, exacerbated by the ongoing El Niño weather phenomenon, have triggered widespread flooding in the southernmost state of Rio Grande do Sul — the worst flooding the region has seen in 80 years. According to the UN Refugee Agency (UNHCR), the floods have affected 93% of the state’s cities. Described by UNHCR as “the biggest ever climate-related disaster ” in southern Brazil, the floods have claimed at least 163 lives and displaced approximately 580,000 people.

A girl walks alongside two women on a debris-strewn road after heavy rains and flooding. People with umbrellas follow behind them.
Flooding and damage in Rio Grande do Sul, southern Brazil, in May 2024, have resulted in the country’s worst flooding in 80 years, affecting more than 1.4 million people. (© 2024 Photo by Alencar da Rosa | Getty Images)

East Africa

In East Africa, El Niño-fueled rains have unleashed floods across the region, affecting multiple countries, including Burundi, Ethiopia, Kenya, Rwanda, Somalia, and Tanzania. Kenya has been hard hit, with nearly half the country experiencing massive flooding since mid-March 2024. Hundreds of people have died, and according to the UN Office for Coordination of Humanitarian Affairs (OCHA), an estimated 1.6 million people are affected, including more than 480,000 displaced as of May 30, 2024 — with numbers continuing to rise. Children are especially vulnerable, with schools disrupted and families in urgent need of support.

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A man in a yellow hard hat carries a young girl with a pacifier and life vest through floodwaters, with a rescue team and boat behind them.
Torrential rains, exacerbated by the ongoing El Niño weather phenomenon, have triggered widespread flooding in Brazil’s southernmost state, Rio Grande do Sol. Amid the flooding and damage, a rescue scene unfolded in May 2024. This deluge began on April 27, 2024, and persisted throughout May. National authorities have rescued 1,000 people through emergency operations, as reported by the Civil Defense of Rio Grande do Sul. World Vision is responding to the crisis and supporting 70,000 households (including 200,000 children) with essential items, shelter kits, and more. (© 2024 Photo by Alencar da Rosa | Getty Images)

Who is most impacted by floods?

While floods can affect any community, they often hit vulnerable populations the hardest. This includes people living in poverty, refugees, and those who are internally displaced, as their shelters and dwellings are often washed away. Lacking adequate infrastructure and resources, people struggle to withstand or recover from flooding events. Even host communities are not spared, facing displacement as they lose their homes to flood waters. Most of the world’s refugees and displaced persons live in areas highly susceptible to weather-related hazards, leaving them vulnerable to increasingly frequent and severe weather extremes like floods.

“Children are one of the most vulnerable groups in the midst of crises, and often have no idea of ​​the magnitude of the events they are experiencing. They find themselves away from home, family and friends… Without an appropriate intervention, these events could leave lasting scars. We must respond now to ensure that they get the support they desperately need,” said Thiago Crucciti, World Vision’s national director in Brazil.

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Where do I find current information and resources on floods?

During severe storms and floods, rely on authoritative sources for emergency information and updates. Here are some resources for current information on flood preparedness:

Global resources:

US–focused resources:

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An aid worker in a World Vision jacket looks toward a cargo plane waiting on the tarmac.
To support communities affected by floods, World Vision, in partnership with Embraer, one of the world’s largest aircraft manufacturers, airlifted 20 tons of supplies, including food, water, and essential items, to Rio Grande do Sul, Brazil. (© 2024 photo courtesy of Marcelo Liotti Jr.)

Where has World Vision most recently responded to floods globally?

World Vision is dedicated to providing essential aid and support to communities impacted by these deadly flooding events. Our teams are delivering clean water, food assistance, shelter, and more to the hardest-hit communities.

  • In Afghanistan , our response is gearing up to support 100,000 people affected by the floods with immediate and longer-term support.
  • In Brazil , we’re delivering relief aid to support 70,000 families, including 200,000 children. Our assistance includes “tenderness kits” for child well-being, which include toys, games, books, and snacks. We’re also assisting with psychosocial support activities, food, bedding items, and personal and family hygiene and cleaning kits.
  • In East Africa , we’re assisting governments and partners in improving disaster response by conducting needs assessments, developing plans, and evacuating people from flooded areas. Our critical interventions include cash assistance, non-food items, health services, and WASH (water, sanitation, and hygiene) programs. Our top priorities are food security, water and sanitation, child protection, shelter, and health services.

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How does World Vision respond to emergencies like floods?

With a presence in nearly 100 countries, World Vision responds swiftly to humanitarian crises around the world. During emergencies, such as devastating floods or earthquakes, we ensure access to critical essentials like food, clean water, shelter, and child protection services. Our commitment extends to safeguarding children and vulnerable communities even in the most challenging environments.

In 2023, World Vision led 78 disaster responses across 59 countries, aiding 35.8 million people in need worldwide. Beyond addressing immediate needs, we continue to support affected people and their communities in their recovery and rebuilding efforts.

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How can I help survivors of floods and other disasters around the world?

  • Pray Join us in praying for children and communities impacted by the aftermath of these catastrophic floods.
  • Give : Your gift will help provide essential care to children and families impacted by floods and emergencies around the world.

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