Severe weather phenomena are

weather Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmosphere, the ...

conditions that are hazardous to human life and property. Severe weather can occur under a variety of situations, but three characteristics are generally needed: a temperature or moisture boundary, moisture, and (in the event of severe, precipitation-based events) instability in the atmosphere.

Examples

Atmospheric

Fog Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Reprint from Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily influ ...

Haar (fog) In meteorology, haar or sea fret is a cold sea fog. It occurs most often on the east coast of Great Britain between April and September, when warm air passes over the cold North Sea. The term is also known as harr, hare, harl, har and hoar. Ca ...

Ice fog Ice fog is a type of fog consisting of fine ice crystals suspended in the air. It occurs only in cold areas of the world, as water droplets suspended in the air can remain liquid down to . It should be distinguished from diamond dust, a pre ...

Electrical storms

Storm A storm is any disturbed state of the natural environment or the atmosphere of an astronomical body. It may be marked by significant disruptions to normal conditions such as strong wind, tornadoes, hail, thunder and lightning (a thunderstorm), ...

s *

Thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are some ...

s **

Multicellular thunderstorm A multicellular thunderstorm cluster is a thunderstorm that is composed of multiple cells, each being at a different stage in the life cycle of a thunderstorm. It appears as several anvils clustered together. A cell is an updraft/downdraft couple ...

Pulse storm In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the nec ...

Squall line A squall line, or more accurately a quasi-linear convective system (QLCS), is a line of thunderstorms, often forming along or ahead of a cold front. In the early 20th century, the term was used as a synonym for cold front (which often are accom ...

Storm cell A storm cell is an air mass that contains up and down drafts in convective loops and that moves and reacts as a single entity, functioning as the smallest unit of a storm-producing system. An organized grouping of thunder clouds will thus be con ...

(single-cell) **

Supercell A supercell is a thunderstorm characterized by the presence of a mesocyclone: a deep, persistently rotating updraft. Due to this, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of thunderstorms ( ...

s, rotating thunderstorms

Fire

Wildfire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identi ...

or bushfire (ignition of wildfires is sometimes by lightning strike, especially in "

dry thunderstorm A dry thunderstorm is a thunderstorm that produces thunder and lightning, but where most of its precipitation evaporates before reaching the ground. Dry lightning refers to lightning strikes occurring in this situation. Both are so common in the ...

s") **

Firestorm A firestorm is a conflagration which attains such intensity that it creates and sustains its own wind system. It is most commonly a natural phenomenon, created during some of the largest bushfires and wildfires. Although the term has been used ...

Fire whirl A fire whirl or fire devil (sometimes referred to as a fire tornado) is a whirlwind induced by a fire and often (at least partially) composed of flame or ash. These start with a whirl of wind, often made visible by smoke, and may occur when in ...

, also called ''firenado'' and ''fire tornado''

Flooding

Flood A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrol ...

s **

Flash flood A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, or tropical storm, or by meltwater from ice or snow flowing ...

s **

Coastal flooding Coastal flooding normally occurs when dry and low-lying land is submerged by seawater. The range of a coastal flooding is a result of the elevation of floodwater that penetrates the inland which is controlled by the topography of the coastal land ...

Tidal flooding Tidal flooding, also known as sunny day flooding or nuisance flooding, is the temporary inundation of low-lying areas, especially streets, during exceptionally high tide events, such as at full and new moons. The highest tides of the year may b ...

Oceans and bodies of water

Harmful algal bloom A harmful algal bloom (HAB) (or excessive algae growth) is an algal bloom that causes negative impacts to other organisms by production of natural phycotoxin, algae-produced toxins, mechanical damage to other organisms, or by other means. HABs are ...

Blue green algae Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blue ...

Red tide A harmful algal bloom (HAB) (or excessive algae growth) is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, mechanical damage to other organisms, or by other means. HABs are sometimes ...

High seas The terms international waters or transboundary waters apply where any of the following types of bodies of water (or their drainage basins) transcend international boundaries: oceans, large marine ecosystems, enclosed or semi-enclosed region ...

High tides Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables can ...

king tide A king tide is an especially high spring tide, especially the perigean spring tides which occur three or four times a year. King tide is not a scientific term, nor is it used in a scientific context. The expression originated in Australia, Ne ...

Ice shove An ice shove (also known as an ice surge, ice push, ice heave, shoreline ice pileup, ice piling, ice thrust, ice tsunami, ice ride-up, or ''ivu'' in Inupiat) is a surge of ice from an ocean or large lake onto the shore. Ice shoves are caused by ...

Rogue wave Rogue waves (also known as freak waves, monster waves, episodic waves, killer waves, extreme waves, and abnormal waves) are unusually large, unpredictable, and suddenly appearing surface waves that can be extremely dangerous to ships, even to lar ...

Seiche A seiche ( ) is a standing wave in an enclosed or partially enclosed body of water. Seiches and seiche-related phenomena have been observed on lakes, reservoirs, swimming pools, bays, harbors, caves and seas. The key requirement for formation of ...

Swell (ocean) A swell, also sometimes referred to as ground swell, in the context of an ocean, sea or lake, is a series of mechanical waves that propagate along the interface between water and air under the predominating influence of gravity, and thus are of ...

Tidal surge A storm surge, storm flood, tidal surge, or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones. It is measured as the rise in water level above the ...

Rip currents A rip current, often simply called a rip (or misleadingly a ''rip tide''), is a specific kind of water current that can occur near beaches with breaking waves. A rip is a strong, localized, and narrow current of water which moves directly away ...

Undertow (water waves) In physical oceanography, undertow is the undercurrent that is moving offshore when waves are approaching the shore. Undertow is a natural and universal feature for almost any large body of water: it is a return flow compensating for the o ...

Whirlpools A whirlpool is a body of rotating water produced by opposing currents or a current running into an obstacle. Small whirlpools form when a bath or a sink is draining. More powerful ones formed in seas or oceans may be called maelstroms ( ). ''Vo ...

Precipitation

Snow

Avalanche An avalanche is a rapid flow of snow down a slope, such as a hill or mountain. Avalanches can be set off spontaneously, by such factors as increased precipitation or snowpack weakening, or by external means such as humans, animals, and ea ...

Blizzard A blizzard is a severe snowstorm characterized by strong sustained winds and low visibility, lasting for a prolonged period of time—typically at least three or four hours. A ground blizzard is a weather condition where snow is not falling ...

Lake effect snow Lake-effect snow is produced during cooler atmospheric conditions when a cold air mass moves across long expanses of warmer lake water. The lower layer of air, heated up by the lake water, picks up water vapor from the lake and rises up through ...

* Snownado ** Snow devil

Ice

Black ice Black ice, sometimes called clear ice, is a thin coating of glaze ice on a surface, especially on streets. The ice itself is not black, but visually transparent, allowing the often black road below to be seen through it. The typically low level ...

Glaze ice Glaze or glaze ice, also called glazed frost, is a smooth, transparent and homogeneous ice coating occurring when freezing rain or drizzle hits a surface. It is similar in appearance to clear ice, which forms from supercooled water droplets. It i ...

Hailstorm Hail is a form of solid precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets generally fal ...

Ice storm An ice storm, also known as a glaze event or a silver storm is a type of winter storm characterized by freezing rain. The U.S. National Weather Service defines an ice storm as a storm which results in the accumulation of at least of ice on ...

Megacryometeor A megacryometeor is a very large chunk of ice which, despite sharing many textural, hydro-chemical, and isotopic features found in large hailstones, is formed under unusual atmospheric conditions which clearly differ from those of the cumulonimbus ...

Rain

Acid rain Acid rain is rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). Most water, including drinking water, has a neutral pH that exists between 6.5 and 8.5, but ac ...

Blood rain Blood rain is a phenomenon where blood is perceived to fall from the sky in the form of rain. Blood Rain may also refer to: * ''Blood Rain'' (film), a 2005 thriller film * ''Blood Rain'' (novel), a 1999 crime novel See also *''BloodRayne'', a ...

* Cold drop ( es, gota fría; archaic as a meteorological term), colloquially, any high impact rainfall event along the Mediterranean coast of Spain *

Drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...

, a prolonged water supply shortage, often caused caused by persistent lack of, or much reduced,

rainfall Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...

s **

Rainstorm Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and then become heavy enough to fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fr ...

* Red rain in Kerala (for related phenomena, see ''Blood rain'')

Surface movement

Mass wasting Mass wasting, also known as mass movement, is a general term for the movement of rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is not entrained in ...

and landslips **

Landslide Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated slope failures, mudflows, and debris flows. Landslides occur in a variety of environmen ...

Mudslide A mudflow or mud flow is a form of mass wasting involving fast-moving flow of debris that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/second. Mudflows contain a signific ...

Rockfall A rockfall or rock-fallWhittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, 1984. . is a quantity/sheets of rock that has fallen freely from a cliff face. The term is also used for collapse of rock from roof or walls of mi ...

Thermal

Cold wave A cold wave (known in some regions as a cold snap, cold spell or Arctic Snap) is a weather phenomenon that is distinguished by a cooling of the air. Specifically, as used by the U.S. National Weather Service, a cold wave is a rapid fall in tem ...

Heat wave A heat wave, or heatwave, is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary, a heat wave is usually measured relative to the usual climate in the ...

Heat burst In meteorology, a heat burst is a rare atmospheric phenomenon characterized by a sudden, localized increase in air temperature near the Earth's surface. Heat bursts typically occur during night-time and are associated with decaying thunderstor ...

* humidity

Wind

Cyclone In meteorology, a cyclone () is a large air mass that rotates around a strong center of low atmospheric pressure, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere as viewed from above (opposite to an an ...

s **

Extratropical cyclone Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are low-pressure areas which, along with the anticyclones of high-pressure areas, drive the weather over much of the Earth. Extratropical cyclones are capable ...

***

European windstorm European windstorms are powerful extratropical cyclones which form as cyclonic windstorms associated with areas of low atmospheric pressure. They can occur throughout the year, but are most frequent between October and March, with peak inte ...

s ** " Medicane", Mediterranean tropical-like cyclones **

Polar cyclone A circumpolar vortex, or simply polar vortex, is a large region of cold, rotating air that encircles both of Earth's polar regions. Polar vortices also exist on other rotating, low-obliquity planetary bodies. The term polar vortex can be used to ...

Tropical cyclone A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Dep ...

, also called a hurricane, typhoon, or just "cyclone" **

Subtropical cyclone A subtropical cyclone is a weather system that has some characteristics of both tropical and an extratropical cyclone. As early as the 1950s, meteorologists were uncertain whether they should be characterized as tropical or extratropical cyclon ...

Explosive cyclogenesis Explosive cyclogenesis (also referred to as a weather bomb, meteorological bomb, explosive development, bomb cyclone, or bombogenesis) is the rapid deepening of an extratropical cyclonic low-pressure area. The change in pressure needed to class ...

or weather bomb *

Dust storm A dust storm, also called a sandstorm, is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface. Fine particles are transp ...

Haboob A haboob ( ar, هَبوب, lit=blasting/drifting, translit=habūb) is a type of intense dust storm carried on an atmospheric gravity current, also known as a weather front. Haboobs occur regularly in dry land area regions throughout the worl ...

Dust devil A dust devil is a strong, well-formed, and relatively short-lived whirlwind. Its size ranges from small (half a metre wide and a few metres tall) to large (more than 10 m wide and more than 1 km tall). The primary vertical motion is ...

Sandstorm A dust storm, also called a sandstorm, is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface. Fine particles are transpo ...

Hurricane A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Dep ...

Katabatic wind A katabatic wind (named from the Greek word κατάβασις ''katabasis'', meaning "descending") is a drainage wind, a wind that carries high-density air from a higher elevation down a slope under the force of gravity. Such winds are sometim ...

s ** Bohemian wind ** Bora ** Gregale **

Santa Ana winds The Santa Ana winds (sometimes devil winds) "Scholars who have looked into the name's origins generally agree that it derives from Santa Ana Canyon, the portal where the Santa Ana River -- as well as a congested Riverside (CA-91) Freeway -- leav ...

Gale A gale is a strong wind; the word is typically used as a descriptor in nautical contexts. The U.S. National Weather Service defines a gale as sustained surface winds moving at a speed of between 34 and 47 knots (, or ).Monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscil ...

Nor’easter A nor'easter (also northeaster; see below), or an East Coast low is a synoptic-scale extratropical cyclone in the western North Atlantic Ocean. The name derives from the direction of the winds that blow from the northeast. The original use o ...

* Nor'westers *

Steam devil A steam devil is a small, weak whirlwind over water (or sometimes wet land) that has drawn fog into the vortex, thus rendering it visible. They form over large lakes and oceans during cold air outbreaks while the water is still relatively wa ...

Squall A squall is a sudden, sharp increase in wind speed lasting minutes, as opposed to a wind gust, which lasts for only seconds. They are usually associated with active weather, such as rain showers, thunderstorms, or heavy snow. Squalls refer to the ...

Straight-line winds In meteorology, a downburst is a strong downward and outward gushing wind system that emanates from a point source above and blows radially, that is, in straight lines in all directions from the area of impact at surface level. Capable of pro ...

Derecho A ''derecho'' (, from es, derecho, link=no , 'straight') is a widespread, long-lived, straight-line wind storm that is associated with a fast-moving group of severe thunderstorms known as a mesoscale convective system. Derechos can cause hurri ...

Tornado A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, alt ...

(also colloquially referred to as a "whirlwind" or "twister") **

Landspout __NOTOC__ Landspout is a term created by atmospheric scientist Howard B. Bluestein in 1985 for a kind of tornado not associated with a mesocyclone. The ''Glossary of Meteorology'' defines a landspout as : "Colloquial expression describing torn ...

Gustnado A gustnado is a brief, shallow surface-based vortex which forms within the downburst emanating from a thunderstorm. The name is a portmanteau by elision of "gust front tornado", as gustnadoes form due to non-tornadic straight-line wind featur ...

, a "

gust front An outflow boundary, also known as a gust front, is a storm-scale or mesoscale boundary separating thunderstorm-cooled air ( outflow) from the surrounding air; similar in effect to a cold front, with passage marked by a wind shift and usually ...

tornado" **

Waterspout A waterspout is an intense columnar vortex (usually appearing as a funnel-shaped cloud) that occurs over a body of water. Some are connected to a cumulus congestus cloud, some to a cumuliform cloud and some to a cumulonimbus cloud. In the ...

Winter storms A winter storm is an event in which wind coincides with varieties of precipitation that only occur at freezing temperatures, such as snow, Rain and snow mixed, mixed snow and rain, or freezing rain. In temperate continental climates, these sto ...

Wind gust A gust or wind gust is a brief increase in the speed of the wind, usually less than 20 seconds. It is of a more transient character than a squall, which lasts minutes, and is followed by a lull or slackening in the wind speed. Generally, winds ar ...

Windstorm A storm is any disturbed state of the natural environment or the atmosphere of an astronomical body. It may be marked by significant disruptions to normal conditions such as strong wind, tornadoes, hail, thunder and lightning (a thunderst ...

Other

Heat lightning Heat lightning, also known as silent lightning, summer lightning, or dry lightning (not to be confused with dry thunderstorms, which are also often called dry lightning), is a misnomer used for the faint flashes of lightning on the horizon or o ...

Zud A zud, dzud ( mn, зуд) of dzhut, zhut, djut, jut ( kz, жұт, ky, жут, russian: джут) is a disaster in steppe, semi-desert and desert regions in Mongolia and Central Asia in which large numbers of livestock die, primarily due to starva ...

, widespread livestock death, mainly by starvation, caused by climatic conditions Some related meteorological terms:

Phenomena caused by severe thunderstorms

* Extreme wind (70 mph or greater) * Downpours *

Heavy rain ''Heavy Rain'' is a 2010 adventure game developed by Quantic Dream and published by Sony Computer Entertainment. The game features four protagonists involved with the mystery of the Origami Killer, a serial murderer who uses extended periods ...

flash flood A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, or tropical storm, or by meltwater from ice or snow flowing ...

coastal flooding Coastal flooding normally occurs when dry and low-lying land is submerged by seawater. The range of a coastal flooding is a result of the elevation of floodwater that penetrates the inland which is controlled by the topography of the coastal land ...

Hail Hail is a form of solid precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets generally fal ...

* High winds – 93 km/h(58 mph) or higher. *

Lightning Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an average ...

Thundersnow Thundersnow, also known as a winter thunderstorm or a thundersnowstorm, is a kind of thunderstorm with snow falling as the primary precipitation instead of rain. It is considered a rare and unusual phenomenon. It typically falls in regions of s ...

Snowsquall A snowsquall, or snow squall, is a sudden moderately heavy snowfall with blowing snow and strong, gusty surface winds. It is often referred to as a whiteout and is similar to a blizzard but is localized in time or in location and snow accumul ...

(gradient pressure induced) *

Severe thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are somet ...

(

hail Hail is a form of solid precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets generally fal ...

storm,

downburst In meteorology, a downburst is a strong downward and outward gushing wind system that emanates from a point source above and blows radially, that is, in straight lines in all directions from the area of impact at surface level. Capable of pro ...

: microbursts and macrobursts)