Severe weather

Severe weather
Name	Severe weather

Severe weather is a category of atmospheric phenomena that pose significant hazards to life, property, and infrastructure, including events such as Hurricane Katrina, Great Galveston Hurricane, Joplin tornado, Superstorm Sandy, and European windstorm Kyrill. These phenomena are studied by organizations such as the National Weather Service, Met Office, Météo-France, Japan Meteorological Agency, and researchers at institutions including Massachusetts Institute of Technology, University of Oklahoma, National Center for Atmospheric Research, Scripps Institution of Oceanography, and Imperial College London. Understanding severe weather draws on historical records from events like the 1883 eruption of Krakatoa (for indirect climatic effects), instrumental datasets from Global Historical Climatology Network, and operational products from agencies such as European Centre for Medium-Range Weather Forecasts and NOAA National Severe Storms Laboratory.

Overview and definitions

Meteorological definitions are codified by agencies such as the World Meteorological Organization, National Oceanic and Atmospheric Administration, Australian Bureau of Meteorology, Environment and Climate Change Canada, and Korea Meteorological Administration, which classify phenomena including tropical cyclones, extratropical cyclones, convective storms, and mesoscale convective systems. Standardized thresholds (wind speed, hail size, precipitation rates) used by the National Hurricane Center, Storm Prediction Center, Servicio Meteorológico Nacional (Mexico), and Instituto Nacional de Meteorología (Spain) distinguish warnings, watches, advisories, and alerts. Regulatory responses reference instruments like the Fujita scale, Enhanced Fujita scale, Saffir–Simpson scale, Beaufort scale, and indices such as the Convective Available Potential Energy and Wind Chill Index in operational contexts.

Types of severe weather

Major categories include tropical cyclones (e.g., Hurricane Harvey, Typhoon Haiyan), tornadoes (e.g., Tri-State tornado, Moore tornado 2013), derechos and squall lines (e.g., 1977 Johnstown derecho), severe thunderstorms (e.g., Supercell Thunderstorm Research cases), hailstorms (e.g., Sydney hailstorm 1999), blizzards (e.g., Great Blizzard of 1888), ice storms (e.g., 1998 North American ice storm), flash floods (e.g., 2010 Pakistan floods), dust storms (e.g., Haboob (Arizona) events), heat waves (e.g., European heat wave 2003), cold waves (e.g., 2014 North American cold wave), and wildland-urban interface fire-weather episodes (e.g., Camp Fire (2018), Black Saturday bushfires). Secondary hazards include storm surge (e.g., Galveston Hurricane 1900), coastal erosion (e.g., North Sea flood of 1953), and landslides (e.g., Vargas tragedy).

Causes and meteorological mechanisms

Atmospheric dynamics driving severe events are examined in contexts such as the Jet stream, El Niño–Southern Oscillation, Madden–Julian oscillation, North Atlantic Oscillation, and Arctic amplification. Mechanisms include baroclinic instability in extratropical cyclones (studied in Jakob Bjerknes frameworks), latent heat release in tropical cyclones (central to work at International Research Institute for Climate and Society), convective initiation in supercells (analyzed by researchers at University of Illinois Urbana-Champaign and University of Oklahoma), and orographic forcing studied in regions like the Rocky Mountains and Alps. Interactions with land-surface processes studied at Stanford University and Colorado State University influence fire-weather episodes and urban heat islands in cities such as New York City and Los Angeles.

Forecasting and warning systems

Forecast methodologies combine numerical weather prediction models (e.g., ECMWF Integrated Forecast System, GFS model, UK Met Office Unified Model), ensemble forecasting techniques developed at European Centre for Medium-Range Weather Forecasts and National Centers for Environmental Prediction, and data assimilation systems using inputs from satellites like GOES, METEOSAT, Himawari, and remote sensing platforms including Doppler radar networks and radiosonde arrays. Warning dissemination uses frameworks by Federal Emergency Management Agency, Civil Protection (Italy), Japan Meteorological Agency, and media outlets; research collaborations like the VORTEX projects, Hazards and Vulnerability Research Institute, and International Research Institute for Climate and Society advance risk communication. Verification metrics from World Meteorological Organization and decision-support tools used by Red Cross and FEMA inform lead times and false-alarm management.

Impacts and hazards

Severe events produce fatalities, economic losses, and infrastructure disruption as documented in case studies such as Hurricane Maria, Tohoku earthquake and tsunami (for cascading hazards), 2011 Joplin tornado, and 2018 Camp Fire. Sectors affected include transportation hubs like LaGuardia Airport and Heathrow Airport, energy systems exemplified by outages in Puerto Rico (2017) and Texas power crisis 2021, and supply chains involving ports such as Port of Shanghai and Port of Rotterdam. Health outcomes (heat-related mortality in Chicago Heat Wave 1995), agricultural impacts (drought and crop failures in Dust Bowl), and ecosystem disturbances (Coral bleaching addressed by NOAA Coral Reef Conservation Program) illustrate breadth of consequences.

Preparedness, mitigation, and response

Mitigation strategies range from structural measures exemplified by the Dutch Delta Works and Mississippi River levee system to nature-based solutions like mangrove restoration in Bangladesh and wetland conservation projects supported by UNEP. Preparedness programs include early-warning systems implemented by Pacific Tsunami Warning Center, community resilience initiatives by International Federation of Red Cross and Red Crescent Societies, evacuation planning in New Orleans post-Hurricane Katrina, and building codes influenced by standards from American Society of Civil Engineers and International Code Council. Emergency response and recovery involve coordination among FEMA, Civil Protection (Spain), United Nations Office for the Coordination of Humanitarian Affairs, and non-governmental organizations like Médecins Sans Frontières.

Historical notable events and case studies

Notable historical events studied for lessons include the 1900 Galveston hurricane, 1886 Charleston earthquake (for port and coastal risk interaction), 1925 Tri-State tornado, 1970 Bhola cyclone, 2005 Hurricane Katrina, 2010 Pakistan floods, 2011 Tōhoku earthquake and tsunami (as a compound hazard case), 2013 European floods, 2017 Hurricane Maria, and 2020 North Atlantic hurricane season. Scientific field campaigns and case studies such as VORTEX2, Hurricane Field Program, Project Stormfury, and TOGA COARE have advanced knowledge of convective and tropical processes, while policy responses trace through inquiries like commissions after Hurricane Katrina and investigations following Chernobyl for emergency management parallels.

Category:Weather