Severe Storm
Definition
Storms are generally classified as a meteorological hazard, caused by short-lived, micro- to meso-scale extreme weather and atmospheric conditions that last from minutes to days (EM-DAT).
Facts and figures
There are several different types of storms distinguished by the strength and characteristics of atmospheric disturbances:
- Convective/local storm: A type of meteorological hazard generated by the heating of air and the availability of moist and unstable air masses. Convective storms range from localized thunderstorms (with heavy rain and/or hail, lightning, high winds, tornadoes) to meso-scale, multi-day events.
- Sandstorm, dust storm: Strong winds carry particles of sand aloft, but generally confined to less than 50 feet (15 metres), especially common in arid and semi-arid environments. A dust storm is also characterised by strong winds but carries smaller particles of dust rather than sand over an extensive area.
- Tornado: A violently rotating column of air that reaches the ground or open water (waterspout).
- Lightning: A high-voltage, visible electrical discharge produced by a thunderstorm and followed by the sound of thunder.
- Winter storm, blizzard: A low pressure system in winter months with significant accumulations of snow, freezing rain, sleet or ice. A blizzard is a severe snow storm with winds exceeding 35 mph (56 km/h) for three or more hours, producing reduced visibility (less than .25 mile (400 m).
- Orographic storm (strong wind): Differences in air pressure resulting in the horizontal motion of air. The greater the difference in pressure, the stronger the wind. Wind moves from high pressure toward low pressure.
- Extratropical storm: A type of low-pressure cyclonic system in the middle and high latitudes (also called mid-latitude cyclone) that primarily gets its energy from the horizontal temperature contrasts (fronts) in the atmosphere.
- Tropical storms: A tropical cyclone originates over tropical or subtropical waters. It is characterised by a warm-core, non-frontal synoptic-scale cyclone with a low pressure centre, spiral rainbands and strong winds. Depending on their location, tropical cyclones are referred to as hurricanes (Atlantic, Northeast Pacific), typhoons (Northwest Pacific), or cyclones (South Pacific and Indian Ocean) (UNDRR, Sendai Framework).
Further information
Related content on the Knowledge Portal
Recommended Practices
Data Source
GP-STAR factsheet
To meet the global challenges, the United Nations adopted several framework agreements, including the Sendai Framework for Disaster Risk Reduction at the Third United Nations World Conference on Disaster Risk Reduction (2015-2030). The framework builds the international reference point for disaster preparedness and focuses on reducing existing and future disaster risks as well as enhancing disaster resilience. In the Sendai framework, seven global targets have been agreed to measure global progress in implementing the framework through quantifiable indicators and to present, compare and evaluate the status and progress uniformly worldwide. The recording of the status and degree of target achievement using the agreed indicators requires the use of various data sources, which must be consistent and comparable in time and space in order to ensure global monitoring.
Noticias
Millions of people in Mozambique, Malawi and Zimbabwe are struggling to cope with the aftermath of Cyclone Idai, which has swept through this part of southeast Africa over the last weeks, leaving devastation in its wake. It is thought that more than two million people in the three countries have been affected, but the extent of destruction is still unfolding.
The authorities and military are working to rescue people, but roads and other transport and communication links are cut off. In order to plan and execute this kind of emergency response it is vital to understand exactly which areas have been affected, especially as accessing people cut off is extremely challenging.
The disaster triggered activations of both the Copernicus Emergency Mapping Service and the... read more
The United Nations Office for Outer Space Affairs (UNOOSA), as part of the support it provides to Member States through its UN-SPIDER programme, has requested the activation of the International Charter "Space and Major Disasters" for monitoring the impact of Cyclone Idai in Zimbabwe, which hit the country's eastern provinces on 15 and 16 March. The Charter was activated on behalf of the United Nations Development Programme (UNDP) Zimbabwe country office.
Geospatial experts from UNDP in Zimbabwe will prepare maps based on satellite images provided through the International Charter. The Copernicus Emergency Management Service - Mapping (EMS) is also working in coordination with the International... read more
Evento
Understanding Risk (UR) Caribbean will be held from 27 May to 1 June 2019 at the University of the West Indies (UWI) Cave Hill Campus’ Errol Barrow Center for Creative Imagination. The event consists of three conference days of plenaries, technical sessions and cultural activities, followed by two days of workshops and side events. It provides space for multimedia exhibits and bilateral meetings.
Following the devastation caused by Hurricanes Irma and Maria in 2017 across the Caribbean, there has been increased emphasis on identifying, assessing and reducing disaster risk in the region. UR Caribbean will provide an informal platform for the public and private sectors, regional disaster risk management agencies, non-governmental organizations, multilateral development banks and donors across the Organization of Eastern Caribbean States, Caribbean Community, and Overseas Countries and Territories to:
- Identify gaps and needs that exist in disaster risk information... read more
