Severe Storm

Cyclone Idai on 13 March 2019 west of Madagascar and heading for Mozambique. Image: ESA.

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).

Related content

News

Hurricane Florence (2018). Image: NASA Earth Observatory.

According to a new study by scientists from NASA and NOAA, tropical cyclones stall more frequently and stay longer near the coastline. This potentially leads to more precipitation over confined locations and thus an aggravation of tropical cyclone hazards for coastal populations.

In the new study, scientists Hall and Kossin examined all tropical cyclones from 1944-2017 in the National Hurricane Center's HURDAT2 database to analyze the position and calculate the average forward speed of each storm that has reached the coastal regions and to investigate the direction of the storm track. They found that 66 storms in the North Atlantic stayed in a coastal region for more... read more

Publishing date: 04/07/2019
Modeled catchment mean annual loss. For clarity, only catchments with a mean annual loss of >$1.5 million have been plotted. Image: Quinn, N., Bates, P. D., Neal, J., Smith, A., Wing, O., Sampson, C., et al. ( 2019).

A recent study, published in the Water Resource Research journal, presents a new method for a spatially realistic national flood risk assessment.

Researchers expanded an existing statistical model, based on U.S. Geological Survey (USGS) river flow data, to simulate a thousand years of potential flood events. By calculating the damage for each event in dollars, they were able to estimate the probability of the United States suffering particular annual flood damages.

Traditional risk flood analysis models assume that the impacts on the entire flood-affected... read more

Publishing date: 04/07/2019
Damage from a 7.4 earthquake and a tsunami that hit the Indonesian island of Sulawesi on 28 September 2018. Image: European Union/Pierre Prakash/Flickr.

In the past year, “there were 315 natural disaster events recorded with 11,804 deaths, over 68 million people affected, and US$131.7 billion in economic losses around the world.” This is according to the Centre for Research on the Epidemiology of Disasters (CRED) in its recently released 2018 Natural Disasters Report

While these 2018 natural disaster values represent a decrease when compared with the annual averages from 2008 to 2017, some geographic areas still experienced great losses of life and damages due to natural hazards. Indonesia was most adversely impacted in terms of lives... read more

Publishing date: 01/07/2019
Floods imaged by Copernicus Sentinel-1.

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... read more

Publishing date: 04/04/2019
The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite acquired this image of the cyclone on March 11, 2019, as it spun across the Mozambique Channel. Image: NASA.

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... read more

Publishing date: 18/03/2019

Data Source

Publishing institution: Canadian Space Agency (CSA)
Publishing institution: European Space Agency (ESA)
ESA's Earth Observation Thematic Exploitation Platform (TEP) is a browser for satellite imagery and specific products on an environmental topic. The TEP platforms are divided into 7 categories: Coastal; Forstry; Geohazards; Hydrology; Polar; Urban; and Food Security. Each platform is a collaborative, virtual work environment providing access to EO data and the tools, processors and Information and Communication Technology resources required to work with them. TEP aims to bridge the gap between the users and the data and tools.
Publishing institution: Airbus Defence & Space
Pleidas, TerraSar-X, SPOT and Elevation data available commercially from airbus, certain sample data sets at various locations available for free.

GP-STAR factsheet

Schematic Workflow for the derivation of an exemplary Sendai indicator using crisis information generated from satellite remote sensing (Source: own figure; Copernicus Emergency Management Service (©European Union), EMSN024, EMSN056)
Publishing institution: German Federal Office of Civil Protection and Disaster Assistance

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... read more

Event

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... read more

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