Flood

Definition

Flood is usually used as a general term to describe the overflow of water from a stream channel into normally dry land in the floodplain (riverine flooding), higher-than–normal levels along the coast and in lakes or reservoirs (coastal flooding) as well as ponding of water at or near the point where the rain fell (flash floods) (IRDR Glossary).

Facts and figures

Floods are the natural hazard with the highest frequency and the widest geographical distribution worldwide. According to the Organization for Economic Cooperation and Development (OECD)  flooding is one of the most common, widespread and destructive natural perils, affecting approximately 250 million people worldwide and causing more than $40 billion in damage and losses on an annual basis (OECD).

Flooding occurs most commonly from heavy rainfall when natural watercourses lack the capacity to convey excess water. It can also result from other phenomena, particularly in coastal areas, by a storm surge associated with a tropical cyclone, a tsunami or a high tide. Dam failure, triggered by an earthquake, for instance, will lead to flooding of the downstream area, even in dry weather conditions.

Various climatic and non-climatic processes can result in different types of floods: riverine floods, flash floods, urban floods, glacial lake outburst floods and coastal floods.

Flood magnitude depends on precipitation intensity, volume, timing and phase, from the antecedent conditions of rivers and the drainage basins (frozen or not or saturated soil moisture or unsaturated) and status. Climatological parameters that are likely to be affected by climate change are precipitation, windstorms, storm surges and sea-level rise (UNDRR).

When floodwaters recede, affected areas are often blanketed in silt and mud. The water and landscape can be contaminated with hazardous materials such as sharp debris, pesticides, fuel, and untreated sewage. Potentially dangerous mold blooms can quickly overwhelm water-soaked structures. Residents of flooded areas can be left without power and clean drinking water, leading to outbreaks of deadly waterborne diseases like typhoid, hepatitis A, and cholera (UNDRR).

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Related content on the Knowledge Portal

  • "Floods caused by the the overflowing of the Bengawan Solo river have driven thousands of Bojonegoro residents from their homes, and was believed to have claimed one live. One dead body was found by a passerby on a flooded road at Simbatan village, Kanor sub distrct, Kanor Police Chief Adjunct Commissioner Susilo, said here on Friday. Thousands of houses were submerged by floodwaters reaching a height of between 1 and 1.5 meter. The floods affected 100 villages including Sukorejo, Ngroworejo and Karangpacar at 14 sub districts in Bojonegoro District. Some 23 elementary school buildings and one junior high school building were also flooded, preventing around 4,000 students from going to school. Some villages at Parengan sub district, Tuban District, East Java, were also inundated. Roads connecting Bojonegoro and Jatirogo, Tuban, were submerged by the flood.

    Source :…

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  • The Andean region of Colombia has been deeply affected by constant rain. The sectors of Antioquia, Tolima, Santander, Cauca and Nari?o amongst others in the Pacific region are in a high state of alert due to floods and landslides.

    Source : Glide number

  • Heavy rainfall between 19 and 28 of January has caused flooding in southern part of Bosnia and Herzegovina. The vast water masses have severely affected the population in the municipalities of Trebinje, Popovo polje, Ravno, Neum and Svitava.

    Source : Glide number

     

    Ressources from OCHA/Reliefweb, click here

  • Heavy rains in February have affected 10,000 families across the country. 20 districts of the city of Santa Cruz were flooded on the 13 Feb.

    Source : Glide number

     

    Ressources from OCHA/Reliefweb, click here

  • Due to a cold front in the Caribbean coast, heavy rains, floods and violent winds have affected thousands of people since early February 2009.

    Source : Glide number

     

    Ressources from OCHA/Reliefweb, click here

  • Heavy rains in Morocco have claimed 24 lives and forced 2,000 people to be evacuated over the past week, interior ministry officials said Saturday.

    Source : Glide number

     

    Heavy rains since 2 February have claimed 24 lives and forced 2,000 to be evacuated over the past week. Rivers rose and houses were swept away in landslides, causing over 2,000 homes to be lost.
    According to the authorities in Rabat, 2,252 houses have been lost and another 328 damaged, with 80,000 hectares (300 square miles) of agricultural land submerged.

    Source : International Charter for "Space and Major disasters"

     

    Map ressources :

    Area of…

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  • Recent heavy rain in the Solomon Islands has caused extensive flooding. The number confirmed dead remains at eight with at least another eight missing. Initial assessments suggest that between 3,000-5,000 people directly affected, with many people being evacuated to higher ground (03/02/2009)

    Source : Glide number

     

    Ressources from OCHA/Reliefweb, click here

  • Major flooding peaked at 6.53 metres at 6pm Tuesday (17th Feb) at Diamantina Lakes, and at 8am was 5.84 metres and falling. Minor flooding continues at Monkira with renewed rises and moderate to major flooding expected by the end of the week. Major flooding continues in the Georgina River between Urandangi and Marion Downs. Moderate flooding continues in Eyre Creek between Bedourie and Glengyle. Major flooding peaked at 9.03 metres at 2pm on 18th Feb at Roxborough Downs, and at 8am was 8.99 metres and falling. Glenormiston is nearing a peak and was 7.27 metres at 7:30am. In addition, Moderate to major flooding continues in the Flinders Rivers and the Norman River.

    Source : Glide number

  • Heavy rains since early last week in the North and Northwestern part of the country resulted in widespread flooding in the provinces of Puerto Plata and Espaillat. 2 deaths were reported, 4,565 people were evacuated and 913 homes were damaged in the communities of Batey, Ginebra, Eslab?n and Jamao. Structural damages were also reported on bridges and roads(PAHO Weekly Report, 24 - 30 Jan 2009).

    Source : Glide number

     

    Ressources from OCHA/Reliefweb, click here

  • 11 killed Source : Emdat

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