Inundación

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).

UN-SPIDER Regional Support Offices with hazard-specific expertise

Related content on the Knowledge Portal

  • In collaboration with the National Commission for Space Activities (CONAE) of Argentina, the Mexican Space Agency (AEM) recently launched a digital platform to improve the integration of satellite data for environmental monitoring in Latin America. The Comprehensive Regional Satellite Information System (SIRIS) provides access to satellite information in order to enhance decision-making and facilitate disaster management.

    The SIRIS platform provides access to satellite imagery for different areas. The platform supplies information on the agriculture and forestry sector to better monitor the impact of natural disasters on agricultural production and woodland. It also offers up-to-date and archived data on fires to strengthen early warning and build long-term resilience. On floods, information provided by SIRIS indicates the water level to improve damage evaluation of the impacted area and facilitate humanitarian relief. In...

    read more
    20/12/2020
  • A new report by the world’s largest humanitarian aid network highlights global disasters, populations most vulnerable to them and the efforts of local institutions in preventing, preparing for and responding to them. The 2020 edition of the World Disasters Report, “Come Heat or High Water”, was launched virtually from the offices of the International Federation of Red Cross and Red Crescent Societies (IFRC) in Vienna on November 16. This year’s report discusses climate- and weather-related disasters and their humanitarian impact. It argues for the usefulness of smart financing and space-based information in disaster management support.

    The report warns that the global effort to address climate change is leaving behind countries...

    read more
    19/11/2020
  • Officially launched in 2015 by the National Aeronautics and Space Administration (NASA), the SMAP mission is an orbiting satellite that measures the amount of wetness in the top layer of soil incrementally every 2-3 days. These Soil Moisture Active Passive (SMAP) measurements rely on radiation frequencies that point to different levels of moisture on the surface of  earth’s soil and are useful for scientists because it allows them to construct maps indicating the level of soil moisture globally. Acknowledging the relevance and usability of this data for the field of disaster management, NASA recently integrated the SMAP data into its Disasters Mapping Portal

    The Disasters Mapping Portal has been developed by the Geographic Informations Systems (GIS) Team at NASA in an effort to make their...

    read more
    25/11/2020
  • A new programme aims to prevent and countermand the loss of tropical forests by facilitating the global availability of high-resolution satellite imagery. Launched by Norway’s Ministry of Climate and Environment in partnership with satellite imagery providers Kongsberg Satellite Services, Planetand Airbus, the Imagery Programme makes use of space-based information to combat the devastating effects of climate change, mitigate disasters and facilitate disaster management efforts worldwide.

    Trees are vital for upholding an environmental equilibrium and deforestation causes a disruption with devastating effects on our climate. Meaningfully, the positive correlation between deforestation and global warming is widely recognized. The impact of deforestation on the environment can be...

    read more
    08/12/2020
  • The European Commission plans to rapidly expand its environmental monitoring programme Copernicus. For this purpose, the European Space Agency (ESA) recently pledged 2.55 billion Euros towards contracts to advance the production of six new Copernicus satellite missions. The final of the six contracts was signed last Thursday between ESA and Thales Alenia Space for a mission that will provide new and important information to climate research and disaster management.

    The high-priority Copernicus Radar Observation System for Europe in L-band (ROSE-L) mission is planned to launch in 2028 for a period of 7.5 years. The ROSE-L mission will orbit Earth every few days at an altitude of 690km and will carry a L-Band synthetic aperture radar (SAR). With a wavelength of approximately 23cm, an...

    read more
    18/12/2020
  • The Disasters programme unit at the National Aeronautics and Space Administration (NASA) recently joined a newly launched online platform aimed at placing anticipatory action on the humanitarian agenda. NASA’s involvement in the Anticipation Hub and the subsequent incorporation of Earth observation (EO) tools, serves to improve the capabilities of anticipatory action globally and demonstrates the potential of utilizing satellite-driven data for anticipatory action in disaster management.

    Anticipatory action in the humanitarian context describes disaster mitigation activities based on in-depth forecast information and risk analysis. This approach has gained traction amongst the humanitarian community in recent years as it is viewed as a more efficient and affordable alternative...

    read more
    02/02/2021
  • A knowledge platform for adaptation action on climate change recently updated the information, layout and logo of their website. With this step, adaptationcommunity.net aims to improve the user experience of the online platform and consequently facilitate the access to a wide variety of resources on climate change adaptation action, including tools working with Earth observation data.

    Adaptation action in the context of climate change refers to “adjustments in ecological, social, or economic systems in response to actual or expected climatic stimuli and their effects or impacts. It refers to changes in processes, practices, and structures to moderate potential damages or to benefit from...

    read more
    12/02/2021
  • A new report outlines the impact of Global Human Settlement Layer (GHSL) data on various policy areas. The 2020 edition of the “Atlas of the Human Planet”, recently published and launched virtually by the Joint Research Centre (JRC) of the European Commission as a deliverable to the Group on Earth Observations (GEO) Human Planet Initiative, explores the impact of GHSL data on various policy areas, including disaster risk management.

    GHSL data refers to “global spatial information, evidence-based analytics and knowledge describing the human presence on the planet”. This data relies on spatial information from Landsat 8, Sentinel-1 and Sentinel-2. It is mainly cost-free and...

    read more
    18/02/2021
  • Recent advances in satellite technology in terms of higher spatial resolution, multi-spectral bands and open data access, have enhanced the ability for the monitoring and management of coastal areas. Satellite images are to be one of the most potential alternatives to water depth estimation due to the wide area coverage, repeatability, and low cost.

    Depth retrieval can be achieved using either Analytical or Empirical Bathymetry methods. Empirical methods need additionally in situ measurements and can follow two approaches: Either the one of Lyzenga et al. (1978, 2006), proposing log-linear correlation between multiband and water depth values, and focusing mainly on removing all other reflected parameters attenuating water bottom signals, or the approach of Stumpf et al. (2003), using a ratio of bands and the difference in attenuation of different bands in water.

    The characteristics of the nearshore are dependent on their bathymetry. Variations in the sea floor can...

    read more
  • The world leading insurance and reinsurance provider Swiss Re recently partnered with the commercial synthetic aperture radar (SAR) satellite operator ICEYE to improve flood modelling and support disaster response efforts around the world.

    A flood is a broad term that refers to “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)“. Floods can pose a severe risk to natural environments, communities and their assets, agricultural areas, infrastructure and they are one of the most...

    read more
    15/03/2021

Term Parents

UN-SPIDER Regional Support Offices with hazard-specific expertise