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A dust storm, also called a sandstorm, is a meteorological phenomenon common in
arid A region is arid when it is characterized by a severe lack of available water, to the extent of hindering or preventing the growth and development Development or developing may refer to: Arts *Development hell, when a project is stuck in d ...

arid
and
semi-arid A semi-arid climate, semi-desert climate, or steppe climate is the climate Climate is the long-term pattern of weather Weather is the state of the atmosphere An atmosphere (from the greek words ἀτμός ''(atmos)'', meaning ' ...
regions. Dust storms arise when a gust front or other strong wind blows loose sand and
dirt Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty. Common types of dirt include: * Dust: a general powder of Organic matter, organic or Mineral, ...

dirt
from a dry surface. Fine particles are transported by
saltation Saltation may refer to: * Saltation (biology), an evolutionary hypothesis emphasizing sudden and drastic change * Saltation (geology), a process of particle transport by fluids * Cutaneous rabbit illusion (sensory saltation), a perceptual illusion ...
and suspension, a process that moves soil from one place and
deposits A deposit account is a bank account maintained by a financial institution in which a customer can deposit and withdraw money. Deposit accounts can be savings accounts, Transaction account#Current accounts, current accounts or any of several other ...
it in another.
Drylands Drylands are defined by a scarcity of water. Drylands are zones where precipitation In meteorology Meteorology is a branch of the atmospheric sciences Atmospheric science is the study of the Earth's atmosphere File:Atmosphere gas ...
around
North Africa North Africa or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in th ...

North Africa
and the
Arabian peninsula The Arabian Peninsula (; ar, شِبْهُ الْجَزِيرَةِ الْعَرَبِيَّة, , "Arabian Peninsula" or , , "Island of the Arabs") is a peninsula of Western Asia, situated northeast of Africa on the Arabian Plate. At , the ...
are the main terrestrial sources of airborne dust. It has been argued that poor management of Earth's drylands, such as neglecting the
fallow Fallow is a farming Agriculture is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary Image:Family watching television 1958.jpg, Exercise trends, Increases in ...

fallow
system, are increasing the size and frequency of dust storms from desert margins and changing both the local and global climate, as well as impacting local economies. The term ''sandstorm'' is used most often in the context of
desert A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to the processes of ...

desert
dust storms, especially in the
Sahara Desert The Sahara (, ; ar, الصحراء الكبرى, ', 'the Greatest Desert') is a desert on the . With an area of , it is the largest hot in the world and the third largest desert overall, smaller only than the deserts of and the northern . ...

Sahara Desert
, or places where sand is a more prevalent soil type than dirt or rock, when, in addition to fine particles obscuring visibility, a considerable amount of larger sand particles are blown closer to the surface. The term ''dust storm'' is more likely to be used when finer particles are blown long distances, especially when the dust storm affects
urban area An urban area, or built-up area, is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as city, cities, towns, conurbat ...
s.


Causes

As the force of dust passing over loosely held particles increases, particles of sand first start to vibrate, then to move across the surface in a process called
saltation Saltation may refer to: * Saltation (biology), an evolutionary hypothesis emphasizing sudden and drastic change * Saltation (geology), a process of particle transport by fluids * Cutaneous rabbit illusion (sensory saltation), a perceptual illusion ...
. As they repeatedly strike the ground, they loosen and break off smaller particles of dust which then begin to travel in suspension. At wind speeds above that which causes the smallest to suspend, there will be a population of dust grains moving by a range of mechanisms: suspension, saltation and creep. A study from 2008 finds that the initial saltation of sand particles induces a static electric field by friction. Saltating sand acquires a negative charge relative to the ground which in turn loosens more sand particles which then begin saltating. This process has been found to double the number of particles predicted by previous theories. Particles become loosely held mainly due to a prolonged drought or arid conditions, and high wind speeds. Gust fronts may be produced by the outflow of rain-cooled air from an intense thunderstorm. Or, the wind gusts may be produced by a dry
cold front A cold front is the leading edge of a cooler mass of air at ground level that replaces a warmer mass of air and lies within a pronounced surface trough Trough may refer to: In science * Trough (geology), a long depression less steep than a tren ...

cold front
: that is, a cold front that is moving into a dry air mass and is producing no
precipitation In meteorology Meteorology is a branch of the (which include and ), with a major focus on . The study of meteorology dates back , though significant progress in meteorology did not begin until the 18th century. The 19th century saw mod ...
—the type of dust storm which was common during the
Dust Bowl The Dust Bowl was a period of severe dust storm A dust storm, also called a sandstorm, is a meteorological phenomenon common in arid A region is arid when it is characterized by a severe lack of available water, to the extent o ...
years in the U.S. Following the passage of a dry cold front,
convective Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity Homogeneity and heterogeneity are concepts often used in the sciences and statistics Statistics ...

convective
instability resulting from cooler air riding over heated ground can maintain the dust storm initiated at the front. In desert areas, dust and sand storms are most commonly caused by either thunderstorm outflows, or by strong pressure gradients which cause an increase in wind velocity over a wide area. The vertical extent of the dust or sand that is raised is largely determined by the stability of the atmosphere above the ground as well as by the weight of the particulates. In some cases, dust and sand may be confined to a relatively-shallow layer by a low-lying
temperature inversion In meteorology Meteorology is a branch of the (which include and ), with a major focus on . The study of meteorology dates back , though significant progress in meteorology did not begin until the 18th century. The 19th century saw m ...
. In other instances, dust (but not sand) may be lifted as high as .
Drought A drought is an event of prolonged shortages in the water supply, whether atmospheric (below-average precipitation In meteorology Meteorology is a branch of the (which include and ), with a major focus on . The study of meteorolog ...

Drought
and
wind Wind is the natural movement of air or other gases relative to a planet's surface. Wind occurs on a range of scales, from thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by th ...

wind
contribute to the emergence of dust storms, as do poor
farming Agriculture is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary Image:Family watching television 1958.jpg, Exercise trends, Increases in sedentary behaviors su ...

farming
and grazing practices by exposing the dust and sand to the wind. One poor farming practice which contributes to dust storms is
dryland farming Dryland farming in the Granada region of Spain Dryland farming and dry farming encompass specific agricultural Agriculture is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentar ...
. Particularly poor dryland farming techniques are intensive tillage or not having established
crop A crop is a plant that can be grown and harvested extensively for profit or subsistence. Crops may refer either to the harvested parts or to the harvest in a more refined state. Most crops are cultivated in agriculture Agriculture is th ...

crop
s or
cover crop In agriculture Agriculture is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentism, sedentary human civilization, whereby farming of domestication, domesticated spec ...
s when storms strike at particularly vulnerable times prior to
revegetation 302x302px, CSIRO ScienceImage 4361 Revegetation of degraded site northern China 1991 Revegetation is the process of replanting and rebuilding the soil Soil (often stylized as SOiL) is an American rock band that was formed in Chicago (''Cit ...
. In a semi-arid climate, these practices increase susceptibility to dust storms. However,
soil conservation Soil conservation is the prevention of loss of the top most layer of the soil from erosion In earth science Earth science or geoscience includes all fields of natural science Natural science is a branch of science Science (from ...
practices may be implemented to control wind erosion.


Physical and environmental effects

A sandstorm can transport and carry large volumes of sand unexpectedly. Dust storms can carry large amounts of dust, with the leading edge being composed of a wall of thick dust as much as high. Dust and sand storms which come off the
Sahara Desert The Sahara (, ; ar, الصحراء الكبرى, ', 'the Greatest Desert') is a desert on the . With an area of , it is the largest hot in the world and the third largest desert overall, smaller only than the deserts of and the northern . ...

Sahara Desert
are locally known as a
simoom Simoom ( ar, سموم ''samūm''; from the root ''s-m-m'', "to poison") is a strong, dry, dust-laden wind. The word is generally used to describe a local wind that blows in the Sahara The Sahara (, ; ar, الصحراء الكبرى, ...
or simoon (sîmūm, sîmūn). The ''
haboob A haboob ( ar, هَبوب, lit=blasting/drifting, translit=habūb) is a type of intense dust storm A dust storm, also called a sandstorm, is a meteorological phenomenon common in arid A region is arid when it is characterized by a s ...
'' (həbūb) is a sandstorm prevalent in the region of
Sudan Sudan ( or ; ar, السودان, as-Sūdān), officially the Republic of the Sudan ( ar, جمهورية السودان, link=no, Jumhūriyyat as-Sūdān), is a country in Northeast Africa. It borders the countries of Central African Republ ...

Sudan
around
Khartoum Khartoum or Khartum ( ; ar, الخرطوم, Al-Khurṭūm) is the capital of Sudan Sudan (; ar, السودان, as-Sūdān), officially the Republic of the Sudan ( ar, جمهورية السودان, link=no, Jumhūriyyat as-Sūdān), is ...

Khartoum
, with occurrences being most common in the summer. The
Sahara The Sahara (, ; ar, الصحراء الكبرى, ', 'the Greatest Desert') is a desert on the African continent Africa is the world's second-largest and second-most populous continent A continent is any of several large landma ...

Sahara
desert is a key source of dust storms, particularly the
Bodélé Depression The Bodélé Depression (), located at the southern edge of the Sahara Desert The Sahara (, ; ar, الصحراء الكبرى, ', 'the Greatest Desert') is a desert on the African continent. With an area of , it is the largest hot dese ...

Bodélé Depression
and an area covering the confluence of
Mauritania Mauritania (; ar, موريتانيا, ', french: Mauritanie; Berber languages, Berber: ''Agawej'' or ''Cengit''; Pulaar language, Pulaar: ''Moritani''; Wolof language, Wolof: ''Gànnaar''; Soninke language, Soninke: ''Murutaane''), officially ...

Mauritania
,
Mali Mali (; ), officially the Republic of Mali (french: République du Mali; bm, ߡߊߟߌ ߞߊ ߝߊߛߏߖߊߡߊߣߊ, Mali ka Fasojamana, ff, 𞤈𞤫𞤲𞥆𞤣𞤢𞥄𞤲𞤣𞤭 𞤃𞤢𞥄𞤤𞤭, Renndaandi Maali, ar, جمهورية م ...

Mali
, and
Algeria ) , image_map = Algeria (centered orthographic projection).svg , map_caption = , image_map2 = , capital = Algiers , coordinates = , largest_city = capital , religion = , official_languages = , languages_type = Oth ...

Algeria
. Sahara dust is frequently emitted into the Mediterranean atmosphere and transported by the winds sometimes as far north as central Europe and Great Britain. Saharan dust storms have increased approximately 10-fold during the half-century since the 1950s, causing
topsoil Topsoil is the upper, outermost layer of soil Soil is a mixture In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements t ...
loss in
Niger ) , official_languages = French , languages_type = National language A national language is a language A language is a structured system of communication used by humans, including speech (spoken language), gestures (Signed languag ...

Niger
,
Chad Chad (; ar, تشاد , ; french: Tchad, ), officially known as the Republic of Chad ( ar, جمهورية تْشَاد, link=no '; ), is a landlocked A landlocked country is a country that does not have territory connected to an oce ...

Chad
, northern
Nigeria Nigeria (), officially the Federal Republic of Nigeria, is a country in West Africa West Africa or Western Africa is the westernmost region of . The defines Western Africa as the 17 countries of , , , , , , , , , , , , , , , and as we ...

Nigeria
, and
Burkina Faso Burkina Faso (, ; ) is a landlocked country in West Africa that covers an area of around and is bordered by Mali to the northwest, Niger to the northeast, Benin to the southeast, Togo and Ghana to the south, and the Ivory Coast to the southwe ...

Burkina Faso
. In Mauritania there were just two dust storms a year in the early 1960s; there are about 80 a year today, according to Andrew Goudie, a professor of geography at Oxford University. Levels of Saharan dust coming off the east coast of Africa in June 2007 were five times those observed in June 2006, and were the highest observed since at least 1999, which may have cooled Atlantic waters enough to slightly reduce hurricane activity in late 2007. Dust storms have also been shown to increase the spread of disease across the globe. Virus spores in the ground are blown into the atmosphere by the storms with the minute particles and interact with urban air pollution. Short-term effects of exposure to desert dust include immediate increased
symptoms Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...

symptoms
and worsening of the lung function in individuals with
asthma Asthma is a long-term Long-Term Capital Management L.P. (LTCM) was a hedge fund''A financial History of the United States Volume II: 1970–2001'', Jerry W. Markham, Chapter 5: "Bank Consolidation", M. E. Sharpe, Inc., 2002 based in Greenwich, ...

asthma
, increased
mortality Mortality is the state of being mortal, or susceptible to death (1906) Death is the permanent, Irreversible process, irreversible cessation of all biological process, biological functions that sustain a living organism. Brain death is some ...
and
morbidity A disease is a particular abnormal condition that negatively affects the structure or function (biology), function of all or part of an organism, and that is not due to any immediate external injury. Diseases are often known to be medical ...
from long-transported dust from both Saharan and Asian dust storms suggesting that long-transported dust storm particles adversely affects the circulatory system. Dust pneumonia is the result of large amounts of dust being inhaled. Prolonged and unprotected exposure of the
respiratory system The respiratory system (also respiratory apparatus, ventilatory system) is a biological system A biological system is a complex network Network and networking may refer to: Arts, entertainment, and media * ''Network'' (1976 film), a 1976 Ame ...

respiratory system
in a dust storm can also cause
silicosis Silicosis is a form of occupational lung disease caused by inhalation of crystalline silica dust. It is marked by inflammation and scarring in the form of nodular lesions in the upper lobes of the lungs. It is a type of pneumoconiosis. Silico ...

silicosis
, which, if left untreated, will lead to
asphyxia Asphyxia or asphyxiation is a condition of deficient supply of oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an ...
tion; silicosis is an incurable condition that may also lead to
lung cancer Lung cancer, also known as lung carcinoma, since about 98–99% of all lung cancers are carcinomas, is a malignant lung tumor characterized by uncontrolled cell growth in tissue (biology), tissues of the lung. Lung carcinomas derive from trans ...

lung cancer
. There is also the danger of
keratoconjunctivitis sicca Dry eye syndrome (DES), also known as keratoconjunctivitis sicca (KCS), is the condition of having dry eyes. Other associated symptoms include irritation, redness, discharge, and easily fatigued eyes. Blurred vision may also occur. The symptoms c ...
("dry eyes") which, in severe cases without immediate and proper treatment, can lead to
blindness Visual impairment, also known as vision impairment or vision loss, is a decreased ability to see to a degree that causes problems not fixable by usual means, such as glasses Glasses, also known as eyeglasses or spectacles, are vision eyew ...
.


Economic impact

Dust storms cause soil loss from the drylands, and worse, they preferentially remove organic matter and the nutrient-rich lightest particles, thereby reducing agricultural productivity. Also, the abrasive effect of the storm damages young crop plants. Dust storms also reduce visibility, affecting aircraft and road transportation. Dust can also have beneficial effects where it deposits: Central and South American rain forests get most of their mineral nutrients from the Sahara; iron-poor ocean regions get iron; and dust in Hawaii increases
plantain Plantain may refer to: * Cooking banana, banana cultivars in the genus ''Musa'' whose fruits are generally used in cooking * True plantains, a group of cultivars of the genus ''Musa'' * ''Plantago'', small inconspicuous plants commonly called plant ...
growth. In northern China as well as the mid-western U.S., ancient dust storm deposits known as
loess Loess (, ; from German ''Löss'' ) is a clastic, predominantly silt-sized sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently sediment transport, transported by ...
are highly fertile soils, but they are also a significant source of contemporary dust storms when soil-securing vegetation is disturbed.


Extraterrestrial dust storms

Dust storms are not limited to Earth and have been known to form on other planets such as
Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, being larger than only Mercury (planet), Mercury. In English, Mars carries the name of the Mars (mythology), Roman god of war and is often referred to ...

Mars
. These dust storms can extend over larger areas than those on Earth, sometimes encircling the planet, with wind speeds as high as . However, given Mars' much lower atmospheric pressure (roughly 1% that of Earth's), the intensity of Mars storms could never reach the kind of hurricane-force winds that are experienced on Earth. Martian dust storms are formed when solar heating warms the Martian atmosphere and causes the air to move, lifting dust off the ground. The chance for storms is increased when there are great temperature variations like those seen at the equator during the Martian summer.


See also

*
Coccidioidomycosis Coccidioidomycosis (, ), commonly known as cocci, Valley fever, as well as California fever, desert rheumatism, or San Joaquin Valley fever, is a mammalian fungal disease caused by '' Coccidioides immitis'' or '' Coccidioides posadasii''. Coccidi ...
*
Dry line A dry line (also called a dew point line, or Marfa front, after Marfa, Texas Marfa is a city in the high desert of the Trans-Pecos in far West Texas West Texas is a loosely defined part of the U.S. state of Texas, generally encompassing the ...
*
Dust storm warning A dust storm warning (SAME code: DSW) is issued by the National Weather Service in the United States when blowing dust is expected to frequently reduce visibility to or less, generally with winds of or more. Beginning November 1, 2018, the Nation ...
*
Haboob A haboob ( ar, هَبوب, lit=blasting/drifting, translit=habūb) is a type of intense dust storm A dust storm, also called a sandstorm, is a meteorological phenomenon common in arid A region is arid when it is characterized by a s ...
* Iberulites * List of dust storms * Mineral dust *
Saharan Air Layer in 2020 Image:Dust particles over Cuba ESA22123159.jpeg, Dust particles can be seen as far as Cuba The Saharan Air Layer (SAL) is an extremely hot, dry and sometimes dust-laden layer of the atmosphere that often overlies the cooler, more-humid ...
*
Shamal (wind) A shamal ( ar, شمال, 'north') is a northwesterly wind Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the bulk movement of air. Winds are commonly classified by their scale (spatial), spatial scale, ...
*
Sirocco Sirocco (), scirocco, ghibli, jugo or, rarely, siroc (see below) is a Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin In biogeography, the Mediterranean Basin (also ...

Sirocco


References


External links


12-hour U.S. map of surface dust concentrations
Mouse-over an hour block on the row for 'Surface Dust Concentrations'


Photos of the April 14 1935 and September 2 1934 dust storms
in the
Texas Panhandle The Texas Panhandle is a region of the U.S. state In the , a state is a , of which there are currently 50. Bound together in a , each state holds al jurisdiction over a separate and defined geographic territory where it shares its with ...
hosted by th
Portal to Texas History.

* [http://news.bbc.co.uk/newsbeat/hi/newsbeat/newsid_7936000/7936912.stm Photos of a sandstorm in Riyadh in 2009] from the BBC Newsbeat website
Dust storm in Phoenix Arizona
via YouTube {{DEFAULTSORT:Dust Storm Weather hazards Road hazards Articles containing video clips Hazards of outdoor recreation