Floods are when water overflows from the normal boundaries of a stream, river or other body of water, or accumulates in an area that is usually dry. There are two main types of floods. Inundation floods are slow and develop over hours or days. Flash floods occur suddenly, often without warning and usually due to heavy rain. Though annual flooding is a natural phenomenon in many parts of the world, human habitation and land-use practices have led to an increase in frequency and size of floods. Floods are also predicted to become even more frequent and severe in future due to climate change. Floods can be extremely dangerous and cause massive human, environmental and material damage to communities.

A Sudan Red Crescent Volunteer wades through deep water to reach a woman affected by severe flooding in Khartoum East in August 2020

Emergency appeals

Do you know how to prepare for a flood?

Do's and don'ts

  • Monitor local weather conditions and listen for official advice
  • Know your area's flood risks
  • Store important documents and hazardous materials high up
  • Identify a safe evacuation route and practise it
  • Avoid building on riverbanks, gullies or flood plains where possible
  • Build and maintain your home with floods in mind
  • Never try to walk, swim or drive through swift water
  • Do not drink contaminated water
  • Clean up carefully after a flood, pumping water from your home slowly
  • Look out for hazards in flood water, such as debris and electrical wires

Watch: How to prepare for a flood