Flood

This Copernicus Sentinel-1 image combines two acquisitions over the same area of eastern Iraq, one from 14 November 2018 before heavy rains fell and one from 26 November 2018 after the storms. The image reveals the extent of flash flooding in red, near the town of Kut. Image: modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO.

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).

Related content on the Knowledge Portal

Noticias

The United Nations Office for Outer Space Affairs (UNOOSA) and the National Aeronautics and Space Administration of the United States Government (NASA) signed a landmark Memorandum of Understanding (MoU) on 17 December 2020 pledging cooperation in areas of science and technology to support the peaceful uses of outer space.

The MoU brings together NASA's wealth of open-source spacecraft data, tools, and expertise and UNOOSA's unique position as the only UN entity dedicated to outer space affairs, to expand global opportunities to leverage the benefits of space. The partners will design capacity-building programmes, particularly for institutions in countries that do not yet have or that are developing space capabilities, to help them access space.

Together, UNOOSA and NASA will develop ways to leverage the Artemis programme as part of UNOOSA's Access to Space 4 All Initiative, which offers opportunities for international researchers and institutions, especially in... read more

Publishing date: 11/01/2021
Snapshot of the SIRIS platform in action. Image: Mexican Space Agency (AEM)

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

Publishing date: 20/12/2020
The signing ceremony of the ROSE-L mission. Image: ESA.

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... read more

Publishing date: 18/12/2020
Official Logo of NICFI. Image: NICFI.

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

Publishing date: 08/12/2020
Screenshot of the SMAP tool in action. Image: NASA

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 satellite data... read more

Publishing date: 25/11/2020
GloFAS forecast for parts of Central America on 3 November.

When disaster looms, early warning about potentially affected areas and the extent of the event are critical for disaster management efforts. Using in situ and satellite-based observations, two web-based systems provide critical information to support flood early warning efforts worldwide, for instance in the context of the current record-setting Atlantic hurricane season, which has brought widespread damage to countries in Central America. The GEOGloWS ECMWF Streamflow Hydroviewer and the Global Flood Awareness System (GloFAS) are easily accessible and free-to-use online tools that present information resulting from complex hydrological modelling in an accessible manner to support disaster management authorities and other stakeholders in preparing for floods. Both systems feature world map viewers that provide an overview of the local as well as the global hydro-meteorological situation. Outlooks from such systems are also increasingly used to take anticipatory humanitarian action... read more

Publishing date: 20/11/2020
Cover of the IFRC World Disasters Report 2020. Image: Indian Red Cross Society.

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 most vulnerable to... read more

Publishing date: 19/11/2020

Evento

Satellite Imagery of the Great Lakes. Image: NASA/GSFC

Natural lakes and man-made reservoirs are a part of Earth’s surface water. Freshwater lakes and reservoirs are used for drinking water, fishing, and recreational activities. Aside from the aesthetic and scenic value added by their presence, lakes support surrounding plant and aquatic ecosystems and wildlife. A variety of factors affect lakes and reservoirs, including climate variability and change, land use, and other watershed activities influencing surface runoff and groundwater. Therefore, monitoring the water quantity and quality of lakes and reservoirs is crucial for their sustainable management. This training focuses on introducing remote sensing observations for monitoring the water level of lakes; a critical surface water component affecting the residential, economical, and recreational sectors in the area. Recent observations of lake bathymetry based on remote sensing observations will also be presented.

Course Format

The online training will... read more

Data Source

Population Density Map. Image: Facebook Connectivity
Publishing institution: Facebook Connectivity Lab, Center for International Earth Science Information Network (CIESIN) - Columbia University
Facebook Connectivity Lab in collaboration with the Center for International Earth Science Information Network (CIESIN) at Colombia University combines machine vision AI with satellite imagery and census information to create population density maps. With the integration of demographic information, specifically related to age and gender, these maps collectively provide information on both the location and the demographic of a population in a certain country. The population density maps cover the majority of countries around the world.
Population Density Map. Image: Facebook Connectivity
Publishing institution: Facebook Connectivity Lab, Center for International Earth Science Information Network (CIESIN) - Columbia University
Facebook Connectivity Lab in collaboration with the Center for International Earth Science Information Network (CIESIN) at Colombia University combines machine vision AI with satellite imagery and census information to create population density maps. With the integration of demographic information, specifically related to age and gender, these maps collectively provide information on both the location and the demographic of a population in a certain country. The population density maps cover the majority of countries around the world.

Pages

Hazard group

Terms in the same hazard group

Zircon - This is a contributing Drupal Theme
Design by WeebPal.