Extratropical cyclones are capable of producing anything from cloudiness and mild showers to heavy gales, thunderstorms and tornadoes. These types of cyclones are defined as large scale low pressure systems that occur in the middle latitudes of the Earth. In contrast with tropical cyclones, extratropical cyclones produce rapid changes in temperature and dew point along broad lines, called weather fronts, the term cyclone applies to numerous types of low pressure areas, one of which is the extratropical cyclone. The descriptor extratropical signifies that this type of cyclone generally occurs outside the tropics and they are termed mid-latitude cyclones if they form within those latitudes, or post-tropical cyclones if a tropical cyclone has intruded into the mid latitudes. Weather forecasters and the public often describe them simply as depressions or lows. Terms like frontal cyclone, frontal depression, frontal low, extratropical low, non-tropical low, Extratropical cyclones are classified mainly as baroclinic, because they form along zones of temperature and dewpoint gradient known as frontal zones.
They can become barotropic late in their cycle, when the distribution of heat around the cyclone becomes fairly uniform with its radius. Extratropical cyclones form anywhere within the regions of the Earth. A study of extratropical cyclones in the Southern Hemisphere shows that between the 30th and 70th parallels, there are an average of 37 cyclones in existence during any 6-hour period, a separate study in the Northern Hemisphere suggests that approximately 234 significant extratropical cyclones form each winter. Extratropical cyclones form along linear bands of temperature/dewpoint gradient with significant vertical wind shear, cyclogenesis, or low pressure formation, occurs along frontal zones near a favorable quadrant of a maximum in the upper level jetstream known as a jet streak. The favorable quadrants are usually at the rear and left front quadrants. The divergence causes air to rush out from the top of the air column and this in turn forces convergence in the low-level wind field and increased upward motion within the column.
The increased upward motion causes atmospheric pressure at ground level to lower and this is because the upward air motion counteracts gravity, lessening the weight of the atmosphere in that location. The lowered pressure strengthens the cyclone, as the cyclone strengthens, the cold front sweeps towards the equator and moves around the back of the cyclone. Meanwhile, its associated warm front progresses more slowly, as the air ahead of the system is denser. Later, the cyclones occlude as the portion of the cold front overtakes a section of the warm front, forcing a tongue, or trowal. Eventually, the cyclone will become cold and begin to weaken. Atmospheric pressure can fall very rapidly when there are upper level forces on the system
A derecho is a widespread, long-lived, straight-line wind storm that is associated with a land-based, fast-moving group of severe thunderstorms. Derechos can cause hurricane-force winds, heavy rains, and they may occur at any time of the year and occur as frequently at night as during the daylight hours. Derecho comes from the Spanish word in adjective form for straight, organized areas of thunderstorm activity reinforce pre-existing frontal zones, and can outrun cold fronts. The resultant mesoscale convective system forms at the point of the best upper level divergence in the pattern in the area of best low level inflow. The convection moves east and toward the equator into the warm sector, when the convection is strong linear or curved, the MCS is called a squall line, with the feature placed at the leading edge of the significant wind shift and pressure rise. Derechos are squall lines that are bow- or spearhead-shaped on weather radar and, squall lines typically bow out due to the formation of a mesoscale high pressure system which forms within the stratiform rain area behind the initial line.
This high pressure area is formed due to strong descending motion behind the squall line, the size of the bow may vary, and the storms associated with the bow may die and redevelop. Warm season derechos in the Northern Hemisphere form in west to flow at mid levels of the troposphere with moderate to high levels of instability. Derechos form within environments of low-level warm air advection and significant low-level moisture and its common definition is a thunderstorm complex that produces a damaging wind swath of at least 250 miles, featuring a concentrated area of convectively-induced wind gusts exceeding 50 knots. Some studies add a requirement that no more two or three hours separate any two successive wind reports. Derechos typically possess a high or rapidly increasing forward speed and they have a distinctive appearance on radar with several unique features, such as the rear inflow notch and bookend vortices, and usually they manifest two or more downbursts. There are four types of derechos, Serial derecho – This type of derecho is usually associated with a deep low.
Single-bow – A very large bow echo around or upwards of 250 miles long and this type of serial derecho is less common than the multi-bow kind. An example of a serial derecho is the derecho that occurred in association with the October 2010 North American storm complex. Multi-bow – Multiple bow derechos are embedded in a squall line typically around 250 miles long. One example of a serial derecho is a derecho that occurred during the 1993 Storm of the Century in Florida. Because of embedded supercells, tornadoes can spin out of these types of derechos and this is a much more common type of serial derecho than the single-bow kind. Multi-bow serial derechos can be associated with line echo wave patterns on weather radar, progressive derecho – A line of thunderstorms take the bow-shape and may travel for hundreds of miles along stationary fronts
Lightning is a sudden electrostatic discharge that occurs during a thunder storm. This discharge occurs between electrically charged regions of a cloud, between two clouds, or between a cloud and the ground. The charged regions in the atmosphere temporarily equalize themselves through this discharge referred to as an if it hits an object on the ground. Lightning causes light in the form of plasma, and sound in the form of thunder, Lightning may be seen and not heard when it occurs at a distance too great for the sound to carry as far as the light from the strike or flash. This article incorporates public domain material from the National Oceanic and Atmospheric Administration document Understanding Lightning, the details of the charging process are still being studied by scientists, but there is general agreement on some of the basic concepts of thunderstorm electrification. The main charging area in a thunderstorm occurs in the part of the storm where air is moving upward rapidly and temperatures range from -15 to -25 Celsius.
At that place, the combination of temperature and rapid upward air movement produces a mixture of super-cooled cloud droplets, small ice crystals, the updraft carries the super-cooled cloud droplets and very small ice crystals upward. At the same time, the graupel, which is larger and denser. The differences in the movement of the precipitation cause collisions to occur, when the rising ice crystals collide with graupel, the ice crystals become positively charged and the graupel becomes negatively charged. The updraft carries the positively charged ice crystals upward toward the top of the storm cloud, the larger and denser graupel is either suspended in the middle of the thunderstorm cloud or falls toward the lower part of the storm. The result is that the part of the thunderstorm cloud becomes positively charged while the middle to lower part of the thunderstorm cloud becomes negatively charged. This part of the cloud is called the anvil. While this is the charging process for the thunderstorm cloud.
In addition, there is a small but important positive charge buildup near the bottom of the cloud due to the precipitation. Many factors affect the frequency, distribution and physical properties of a lightning flash in a particular region of the world. These factors include ground elevation, prevailing wind currents, relative humidity, proximity to warm and cold bodies of water, to a certain degree, the ratio between IC, CC and CG lightning may vary by season in middle latitudes. Lightnings relative unpredictability limits a complete explanation of how or why it occurs, the actual discharge is the final stage of a very complex process. At its peak, a thunderstorm produces three or more strikes to the Earth per minute
A supercell is a thunderstorm that is characterized by the presence of a mesocyclone, a deep, persistently rotating updraft. For this reason, these storms are referred to as rotating thunderstorms. Of the four classifications of thunderstorms, supercells are the overall least common and have the potential to be the most severe, supercells are often isolated from other thunderstorms, and can dominate the local weather up to 32 kilometres away. Supercells are often put into three types, Low-precipitation, and High-precipitation. LP supercells are found in climates that are more arid, such as the high plains of the United States. Supercells are usually isolated from other thunderstorms, although they can sometimes be embedded in a squall line. Typically, supercells are found in the sector of a low pressure system propagating generally in a north easterly direction in line with the cold front of the low pressure system. Because they can last for hours, they are known as quasi-steady-state storms, supercells have the capability to deviate from the mean wind.
If they track to the right or left of the wind, they are said to be right-movers or left-movers. Supercells can sometimes develop two separate updrafts with opposing rotations, which splits the storm into two supercells, one left-mover and one right-mover, supercells can be any size – large or small, low or high topped. They usually produce copious amounts of hail, torrential rainfall, strong winds, supercells are one of the few types of clouds that typically spawn tornadoes within the mesocyclone, although only 30% or fewer do so. Supercells can occur anywhere in the world under the weather conditions. The first storm to be identified as the type was the Wokingham storm over England. Browning did the work that was followed up by Lemon. Supercells occur occasionally in many other regions, including eastern China. The areas with highest frequencies of supercells are similar to those with the most occurrences of tornadoes, see tornado climatology and Tornado Alley. The current conceptual model of a supercell was described in Severe Thunderstorm Evolution and Mesocyclone Structure as Related to Tornadogenesis by Leslie R.
Lemon, supercells derive their rotation through tilting of horizontal vorticity caused by wind shear. Strong updrafts lift the air turning about an axis and cause this air to turn about a vertical axis
A microburst is a small downdraft that moves in a way opposite to a tornado. Microbursts are found in strong thunderstorms, there are two types of microbursts within a thunderstorm, wet microbursts and dry microbursts. They go through three stages in their cycle, the downburst and cushion stages, a microburst can be particularly dangerous to aircraft, especially during landing, due to the wind shear caused by its gust front. A microburst often has high winds that can knock over fully grown trees and they usually last from a couple of seconds to several minutes. Fujita coined the term macroburst for downbursts larger than 4 km, a distinction can be made between a wet microburst which consists of precipitation and a dry microburst which typically consists of virga. Microbursts are recognized as capable of generating wind speeds higher than 75 m/s, Microbursts have been called air bombs. When rain falls below the base or is mixed with dry air, it begins to evaporate. The cool air descends and accelerates as it approaches the ground, when the cool air approaches the ground, it spreads out in all directions and this divergence of the wind is the signature of the microburst.
High winds spread out in type of pattern showing little or no curvature are known as straight-line winds. Wet microbursts are downbursts accompanied by significant precipitation at the surface which are warmer than their environment and these downbursts rely more on the drag of precipitation for downward acceleration of parcels than negative buoyancy which tend to drive dry microbursts. As a result, higher mixing ratios are necessary for these downbursts to form, melting of ice, particularly hail, appears to play an important role in downburst formation, especially in the lowest 1 km above ground level. These factors, among others, make forecasting wet microbursts a difficult task, the evolution of downbursts is broken down into three stages, the contact stage, the outburst stage, and the cushion stage. The virtual temperature correction usually is small and to a good approximation. In some storms this term has an effect on updrafts but there is not much reason to believe it has much of an impact on downdrafts.
The second term is the effect of buoyancy on vertical motion, clearly, in the case of microbursts, one expects to find that B is negative meaning the parcel is cooler than its environment. This cooling typically takes place as a result of phase changes, precipitation particles that are small, but are in great quantity, promote a maximum contribution to cooling and, hence, to creation of negative buoyancy. The major contribution to this process is from evaporation, the last term is the effect of water loading. Whereas evaporation is promoted by large numbers of small droplets, it requires a few large drops to contribute substantially to the downward acceleration of air parcels
Graupel, called soft hail or snow pellets, is precipitation that forms when supercooled droplets of water are collected and freeze on falling snowflakes, forming 2–5 mm balls of rime. The term graupel comes from the German language, the METAR code for graupel is GS. Under some atmospheric conditions, snow crystals may encounter supercooled water droplets and these droplets, which have a diameter of about 10 µm, can exist in the liquid state at temperatures as low as −40 °C, far below the normal freezing point. Contact between a crystal and the supercooled droplets results in freezing of the liquid droplets onto the surface of the crystal. This process of growth is known as accretion. Crystals that exhibit frozen droplets on their surfaces are referred to as rimed. When this process continues so that the shape of the snow crystal is no longer identifiable. Graupel was formerly referred to by meteorologists as soft hail, graupel is easily distinguishable from hail in both the shape and strength of the pellet and the circumstances in which it falls.
Ice from hail is formed in hard, relatively uniform layers, graupel forms fragile, oblong shapes and falls in place of typical snowflakes in wintry mix situations, often in concert with ice pellets. Graupel is fragile enough that it will fall apart when touched. However, observations of snow crystals with a scanning electron microscope clearly show cloud droplets measuring up to 50 µm on the surface of the crystals. The rime has been observed on all four forms of snow crystals, including plates, columns. As the riming process continues, the mass of frozen, accumulated cloud droplets obscures the form of the snow crystal. Graupel commonly forms in high-altitude climates and is denser and more granular than ordinary snow, due to its rimed exterior. Macroscopically, graupel resembles small beads of polystyrene, the combination of density and low viscosity makes fresh layers of graupel unstable on slopes, and layers of 20–30 cm present a high risk of dangerous slab avalanches. In addition, thinner layers of graupel falling at low temperatures can act as ball bearings below subsequent falls of more stable snow.
Graupel tends to compact and stabilise approximately one or two days after falling, depending on the temperature and the properties of the graupel, merriam-Webster Online Dictionary, accessed September 12,2006. The Weather Channel, accessed September 12,2006, national Snow and Ice Data Center, accessed September 12,2006
A dust devil is a strong, well-formed, and relatively long-lived whirlwind, ranging from small to large. The primary vertical motion is upward, Dust devils are usually harmless, but can on rare occasions grow large enough to pose a threat to both people and property. They are comparable to tornadoes in both are a weather phenomenon of a vertically oriented rotating column of wind. Most tornadoes are associated with a larger parent circulation, the mesocyclone on the back of a supercell thunderstorm, Dust devils form as a swirling updraft under sunny conditions during fair weather, rarely coming close to the intensity of a tornado. In the southwestern United States, a dust devil is called a dancing devil. In Death Valley, California, it may be called an auger or a dust whirl. The Navajo refer to them as chiindii, ghosts or spirits of dead Navajos, if a chindi spins clockwise, it is said to be a good spirit, if it spins counterclockwise, it is said to be a bad spirit. The Australian English term willy-willy or whirly-whirly is thought to derive from Yindjibarndi or a neighbouring language, in Aboriginal myths, willy-willies represent spirit forms.
They are often quite scary spirits, and parents may warn their children if they misbehave. There is a story of the origin of the brolga in which a bad spirit descends from the sky and captures the young being, in Saudi Arabia, Kuwait and Jordan, they often reach hundreds of meters in height and are referred to as djin. Egypt has its fasset el afreet, or ghosts wind, in Iran, this kind of wind is usually called Gerd Baad, or round wind. Among the Kikuyu of Kenya, the dust devil is known as ngoma cia aka, in Brazil, a dust devil is called redemoinho after moinho de vento. In some traditions, it contains a dancing Saci, sometimes it is associated to local religion and beliefs. In Portugal it is known locally as remoinho, Dust devils form when hot air near the surface rises quickly through a small pocket of cooler, low-pressure air above it. If conditions are just right, the air may begin to rotate, the secondary flow in the dust devil causes other hot air to speed horizontally inward to the bottom of the newly forming vortex.
As more hot air rushes in toward the developing vortex to replace the air that is rising, a dust devil, fully formed, is a funnel-like chimney through which hot air moves, both upwards and in a circle. As the hot air rises, it cools, loses its buoyancy, as it rises, it displaces air which descends outside the core of the vortex. This cool air returning acts as a balance against the spinning hot-air outer wall, the spinning effect, along with surface friction, usually will produce a forward momentum
A season is a division of the year marked by changes in weather and hours of daylight. Seasons result from the orbit of the Earth around the Sun. During May and July, the northern hemisphere is exposed to direct sunlight because the hemisphere faces the sun. The same is true of the hemisphere in November, December. It is the tilt of the Earth that causes the Sun to be higher in the sky during the months which increases the solar flux. However, due to lag, June and August are the hottest months in the northern hemisphere and December, January. In temperate and subpolar regions, four calendar-based seasons are recognized, summer, autumn or fall. Ecologists often use a model for temperate climate regions, vernal, serotinal, autumnal. Many tropical regions have two seasons, the rainy, wet, or monsoon season and the dry season, some have a third cool, mild, or harmattan season. Seasons often held special significance for agrarian societies, whose lives revolved around planting and harvest times, in some parts of the world, some other seasons capture the timing of important ecological events such as hurricane season, tornado season, and wildfire season.
The most historically important of these are the three seasons—flood and low water—which were previously defined by the annual flooding of the Nile in Egypt. The seasons result from the Earths axis of rotation being tilted with respect to its orbital plane by an angle of approximately 23.5 degrees, regardless of the time of year, the northern and southern hemispheres always experience opposite seasons. This is because during summer or winter, one part of the planet is directly exposed to the rays of the Sun than the other. For approximately half of the year, the northern hemisphere tips toward the Sun, for the other half of the year, the same happens, but in the southern hemisphere instead of the northern, with the maximum around December 21. The two instants when the Sun is directly overhead at the Equator are the equinoxes. Also at that moment, both the North Pole and the South Pole of the Earth are just on the terminator, and hence day and night are equally divided between the northern and southern hemispheres.
Around the March equinox, the northern hemisphere will be experiencing spring as the hours of daylight increase, the effect of axial tilt is observable as the change in day length and altitude of the Sun at noon during a year. Between this effect and the daylight hours, the axial tilt of the Earth accounts for most of the seasonal variation in climate in both hemispheres
Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and precipitated—that is, become heavy enough to fall under gravity. Rain is a component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides suitable conditions for many types of ecosystems, as well as water for power plants. The major cause of production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts. If enough moisture and upward motion is present, precipitation falls from convective clouds such as cumulonimbus which can organize into narrow rainbands. On the leeward side of mountains, desert climates can exist due to the dry air caused by downslope flow which causes heating and drying of the air mass, the movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes. The urban heat island effect leads to increased rainfall, both in amounts and intensity, downwind of cities, global warming is causing changes in the precipitation pattern globally, including wetter conditions across eastern North America and drier conditions in the tropics.
The globally averaged annual precipitation over land is 715 mm, climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes. Rainfall is measured using rain gauges, rainfall amounts can be estimated by weather radar. Rain is known or suspected on other planets, where it may be composed of methane, sulfuric acid, or even iron rather than water. Air contains water vapor, and the amount of water in a mass of dry air. The amount of moisture in air is commonly reported as relative humidity. How much water vapor a parcel of air can contain before it becomes saturated, warmer air can contain more water vapor than cooler air before becoming saturated. Therefore, one way to saturate a parcel of air is to cool it, the dew point is the temperature to which a parcel must be cooled in order to become saturated. There are four mechanisms for cooling the air to its dew point, adiabatic cooling, conductive cooling, radiational cooling.
Adiabatic cooling occurs when air rises and expands, the air can rise due to convection, large-scale atmospheric motions, or a physical barrier such as a mountain. Conductive cooling occurs when the air comes into contact with a surface, usually by being blown from one surface to another. Radiational cooling occurs due to the emission of infrared radiation, either by the air or by the surface underneath, evaporative cooling occurs when moisture is added to the air through evaporation, which forces the air temperature to cool to its wet-bulb temperature, or until it reaches saturation
A subtropical cyclone is a weather system that has some characteristics of a tropical and an extratropical cyclone. As early as the 1950s, meteorologists were unclear whether they should be characterized as tropical or extratropical cyclones and they were officially recognized by the National Hurricane Center in 1972. Subtropical cyclones began to receive names from the tropical cyclone lists in the North Atlantic, South-west Indian Ocean. There are two currently used for subtropical cyclones. Across the north Atlantic and southwest Indian Ocean, they require central convection fairly near the center, across the eastern half of the northern Pacific, they require a mid-tropospheric cyclone to cut off from the main belt of the westerlies and only a weak surface circulation. Subtropical cyclones have broad wind patterns with maximum sustained winds located farther from the center than typical tropical cyclones and this means that subtropical cyclones are more likely to form outside the traditional bounds of the North Atlantic hurricane season.
Subtropical cyclones are observed to form in the South Atlantic. Throughout the 1950s and 1960s, the term semi-tropical and quasi-tropical were used for what would become known as subtropical cyclones, the term subtropical cyclone merely referred to any cyclone located in the subtropical belt near and just north of the horse latitudes. Intense debate ensued in the late 1960s, after a number of hybrid cyclones formed in the Atlantic Basin, in 1972, the National Hurricane Center finally designated these storms as subtropical cyclones in real-time, and updated the hurricane database to include subtropical cyclones from 1968 through 1971. This name was not noted as controversial in contemporary news reports, in the North Atlantic basin, subtropical cyclones were initially named from the NATO phonetic alphabet list in the early to mid-1970s. In the intervening years of 1975–2001, subtropical storms were named from the traditional list and considered tropical in real-time. Between 1992 and 2001, two different numbers were given to subtropical depressions or subtropical storms, one for public use, for example, Hurricane Karen in 2001 was initially known as Subtropical Storm One as well as AL1301.
In 2002, the NHC began giving numbers to subtropical depressions, from 2002 onwards, Subtropical Depression 13L would be known as Subtropical Depression Thirteen instead. Hurricane Gustav of 2002 was the first Subtropical Storm to receive a name but became tropical shortly after naming, Subtropical Storm Nicole, from the 2004 Atlantic hurricane season was the first subtropical storm that did not become tropical since the policy change. A subtropical storm from the 2005 Atlantic hurricane season did not become tropical, in the southern Indian Ocean, subtropical cyclones are named once winds reach tropical storm, or gale, force. Since 2011, subtropical storms in the South Atlantic Ocean are named by the Brazilian Navy Hydrographic Center, Subtropical cyclones form in a wide band of latitude, mainly south of the 50th parallel in the northern hemisphere. In the case of the north Indian Ocean, the formation of type of vortex leads to the onset of monsoon rains during the wet season. In the southern hemisphere, subtropical cyclones are observed across southern portions of the Mozambique Channel
In meteorology, a cyclone is a large scale air mass that rotates around a strong center of low atmospheric pressure. A cyclone differs from a hurricane or typhoon only on the basis of location, a hurricane is a storm that occurs in the Atlantic Ocean and northeastern Pacific Ocean, a typhoon occurs in the northwestern Pacific Ocean, and a cyclone occurs in the south Pacific or Indian Ocean. Cyclones are characterized by inward spiraling winds that rotate about a zone of low pressure, the largest low-pressure systems are polar vortices and extratropical cyclones of the largest scale. Warm-core cyclones such as cyclones and subtropical cyclones lie within the synoptic scale. Mesocyclones and dust devils lie within the smaller mesoscale, Upper level cyclones can exist without the presence of a surface low, and can pinch off from the base of the Tropical Upper Tropospheric Trough during the summer months in the Northern Hemisphere. Cyclones have seen on extraterrestrial planets, such as Mars. Cyclogenesis describes the process of formation and intensification.
Extratropical cyclones begin as waves in large regions of enhanced mid-latitude temperature contrasts called baroclinic zones and these zones contract and form weather fronts as the cyclonic circulation closes and intensifies. Later in their cycle, extratropical cyclones occlude as cold air masses undercut the warmer air. A cyclones track is guided over the course of its 2 to 6 day life cycle by the flow of the subtropical jet stream. Weather fronts mark the boundary between two masses of air of different temperature and densities, and are associated with the most prominent meteorological phenomena. Strong cold fronts typically feature narrow bands of thunderstorms and severe weather, such fronts form west of the circulation center and generally move from west to east, warm fronts form east of the cyclone center and are usually preceded by stratiform precipitation and fog. Warm fronts move poleward ahead of the cyclone path, occluded fronts form late in the cyclone life cycle near the center of the cyclone and often wrap around the storm center.
Tropical cyclogenesis describes the process of development of tropical cyclones, Tropical cyclones form due to latent heat driven by significant thunderstorm activity, and are warm core. Cyclones can transition between extratropical and tropical phases, mesocyclones form as warm core cyclones over land, and can lead to tornado formation. Waterspouts can form from mesocyclones, but more often develop from environments of high instability, henry Piddington published almost 40 papers dealing with tropical storms from Calcutta between 1835 and 1855 in The Journal of the Asiatic Society. He coined the term cyclone, meaning the coil of a snake, in 1842, he published his landmark thesis, Laws of the Storms. There are a number of characteristics common to all cyclones
A haboob is a type of intense dust storm carried on an atmospheric gravity current, known as a weather front. Haboobs occur regularly in arid regions throughout the world, during thunderstorm formation, winds move in a direction opposite to the storms travel, and they move from all directions into the thunderstorm. When the storm collapses, and begins to release precipitation, wind directions reverse, gusting outward from the storm, Haboobs can form when a strong thunderstorm weakens rapidly, and releases a microburst. When this downdraft of cold air, or downburst, reaches the ground, it blows dry, loose silt and clay up from the desert and this wall of dust can be up to 100 km wide and several kilometers in elevation. At their strongest, haboob winds often travel at 35–100 km/h, often rain does not appear at ground level as it evaporates in the hot, dry air. The evaporation cools the air even further and accelerates it. Occasionally, when the rain does persist, it can contain a quantity of dust.
Severe cases are called mud storms and respiratory system protection are advisable for anyone who must be outside during a haboob. Moving to shelter is highly advised during a strong event, Haboobs have been observed in the Sahara desert, as well as across the Arabian Peninsula, throughout Kuwait, and in the most arid regions of Iraq. Haboob winds in the Arabian Peninsula, Kuwait are frequently created by the collapse of a thunderstorm, african haboobs result from the northward summer shift of the inter-tropical front into North Africa, bringing moisture from the Gulf of Guinea. Haboobs in Australia may be associated with cold fronts. As with haboobs in the Arabian Peninsula and Kuwait, the arid and semiarid regions of North America—in fact, any dry region—may experience haboobs. In North America, the most common terms for these events are either dust storm or sandstorm. In the U. S. they frequently occur in the deserts of Arizona, including around the cities of Yuma and Phoenix, in New Mexico, including Albuquerque, in eastern California, and in Texas.
They sometimes accur in the Columbia Basin, of Eastern Washington, if the storms are strong enough, they can reach as far east as the Rathdrum Prairie and the Palouse, in the Idaho Panhandle Global dust storms on Mars have been compared to haboobs on Earth. Haboob Photos @ HikeArizona. COM Haboobs, Arizona Department of Transportation, the Bibliography of Aeolian Research Haboob on Winds of the World Short Video of the 5 July 2011 Arizona Haboob on YouTube Time-lapse video of the 5 July 2011 Arizona Haboob