All about floods: causes, dangers, and ways to stay safe

30 September 2026 ·Chong Tee Lim

Did you know that floods account for most of today’s weather-related natural disasters? They have affected 2.3 billion between 1995 and 2015, with a vast majority of those affected living in Asia alone. As the annual average number of floods increases drastically over recent years, do you know how to stay safe during a flood?

Global flood hazard distribution from 1985 to 2003

This map highlights extreme floods from 1985-2003. Flooding is visible in more than 1/3 of the world's land area. Source: SEDAC, Columbia University

What causes floods?

Floods occur for a myriad of reasons: as the world's climate changes, we are seeing a rise in weather-related floods; but some major flood disasters are also caused by man made human error. We'll talk about that later!

Rising sea levels combined with seasonal tide cause low-lying regions around the world to be prone to coastal flooding. Some of these floods can be predicted with historical data, allowing people to be more prepared for it. Phew! However, the higher salt content of sea water results in greater corrosion of metals and breaks down organic materials, creating significant structural damage.

A little boy in Jakarta, walking by a house that has been submerged in water due to rising sea levels

Source: The New York Times

Global rainfall distribution from 1901 to 2015, showcasing excessive rainfall over a short period of time in recent years

Source: United States Environmental Protection Agency

By comparison, excessive and intense rainfall over a short period of time is a very common cause of today’s dangerous flash floods. Extreme rains cause the drainage system to be unable to keep up with the rate of rainfall. The situation is further exacerbated when the afflicted area has a river flowing through it, as the rainfall can cause the river to overflow into surrounding communities. Landscapes that have been changed through deforestation have less of a natural barrier to slow floods and protect communities.

With global precipitation in an upward trend, it's likely that we'll see an increasing number of floods as well.

An unexpected cause of floods is when an existing dam holding a huge body of water fails and releases the water stored, leading to a sudden release of water. Although comparatively rarer than excessive rainfall, these floods have the potential to cause catastrophic damage due to the sheer volume of water released.

What is most unfortunate is that the dam failures caused by a lack of funding for upkeep and maintenance are completely preventable. The video above from The Guardian captures the immense scale of a flash flood resulting from a dam failure in Brazil.

Dangers of Flood Water

Flash flooding is the most dangerous type of flooding as it’s unpredictable and involves fast moving water. With the increasing frequency of extreme weather events, we can expect an increase in the frequency of flash floods around the world. Furthermore, floodwater is usually underestimated by people, without knowing that it only requires 15 centimetres of water to sweep a person off their feet.

Aside from the immediate dangers of flash flooding, floodwater in general is a dangerous entity on its own as it’s usually contaminated with sewage and carries physical debris that can cause trauma upon being struck.

Preparing for a flood

If you happen to live in an area that’s at risk of flooding, the following are some measures you can take to prepare if a flood is imminent

Water purification solutions such as chlorine tablets or filtration devices that are independent of electricity, like our ROAMFilter™ Plus, should be accessible.

The ROAMfilter Plus which is a portable water filtration system that is ideal for disaster response

Identify safe zones such as high grounds that you can relocate to quickly.

A large number of people in Kashmiri that are relocating, away from flood disaster zones to higher grounds

Photo by Pok Rie from Pexels

First-aid kit and basic first aid knowledge can help prevent serious injuries and save lives. Try to keep the first-aid kit waterproof as the supplies might get damaged in floodwater

A first aid kit for disaster response that must be kept waterproof to not get damaged from floodwater

Emergency food in cans or packages that can be stored for prolonged periods of time and are not susceptible to contamination by flood water

Canned food for emergency that can be stored for a long period of time

What to do during a flood

Abandon your vehicle

Many people make the false assumption that staying in their vehicle will keep them safe from the floodwater, but this couldn’t be further from the truth. Almost half of all drowning fatalities are car related.

Don't drink unfiltered water
Untreated floodwater often contains many contaminants such as faecal matter, chemical substances and physical debris. Drinking floodwater can expose one to diarrheal diseases, leading to dehydration and even death.

Relocate to higher grounds

Whenever possible, try to relocate to higher ground. However, avoid doing this if it involves navigating through floodwater.

Maintain a line of communication
Either ensure your handphone is fully charged or have a waterproof radio to listen for evacuation orders and other relevant information from the authorities.

Avoid electrical hazards

Avoid any fallen electrical poles as they might still be live and can conduct electricity through flood water.

Turn off utilities at the main source and disconnect all electrical appliances in affected flooded areas.

Avoid exposure of open wounds to flood water
Open wounds are a gateway for bacteria into the human body. As covered above, floodwater is full of dangerous bacteria and one should avoid exposing open wounds to the contaminated water. Clean any wounds with clean water to avoid infection.

Although they are not the deadliest type of natural disaster, floods occur at a high frequency and have the potential to displace a large number of people, especially among the lower-income regions. As countries develop economically, they’re better able to deal with the human cost of floods through better infrastructure and flood response networks.

The ROAMfilter Plus used as a flood disaster relief water filter

However, economic progress and building of infrastructure takes time and the people currently living in these flood-prone regions do not have that luxury of time. Until these improvements come, education on flood preparation and response plays an important role in saving lives.

Think you might be affected by a flood?

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Blog Author: Jien Wei Tan
Chief Editor: Michelle Falcone

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