Sand desert hurricane scanword 5 letters. Sandstorm. What to do if caught in a storm

These climatic phenomena make a significant contribution to the pollution of the earth's atmosphere. It is one of the many incredible natural phenomena to which scientists quickly found a simple explanation.

These adverse climatic events are dust storms. They will be described in more detail in the following article.

Definition

A dusty or sandstorm is a phenomenon of the transfer of a huge amount of sand and dust by strong winds, which is accompanied by a sharp deterioration in visibility. As a rule, such phenomena originate on land.

These are arid areas of the planet, from where powerful air clouds of dust carry the air currents into the ocean. Moreover, representing a considerable danger to humans mainly on land, they nevertheless greatly worsen the transparency of atmospheric air, making it difficult to observe the surface of the ocean from space.

The thing is in the terrible heat, due to which the soil dries out strongly and then in the surface layer breaks up into microparticles picked up by a strong wind.

But dust storms begin at certain critical values \u200b\u200bdepending on the topography and soil structure. Mostly they start at wind speeds in the range of 10-12 m / s. And on slight dust storms occur in summer even at speeds of 8 m / s, less often at 5 m / s.

Behavior

The duration of the storms varies from minutes to several days. Most often, the time is calculated in hours. For example, an 80-hour storm was recorded in the Aral Sea region.

After the disappearance of the causes of the described phenomenon, the raised dust from the surface of the earth remains in the air in suspension for several hours, possibly a day. In these cases, its enormous masses are carried by air currents for hundreds and even thousands of kilometers. The dust carried by the wind at large distances from the source is called the advective haze.

Tropical air masses carry this haze to the southern part of Russia and all of Europe from Africa (its northern regions) and the Middle East. And western flows often carry such dust from China (center and north) on the Pacific coast, etc.

Color

Dust storms have the most varied color, which depends on their color. There are storms of the following colors:

• black (black soil of the southern and southeastern regions of the European part of Russia, Orenburg region and Bashkiria);
• yellow and brown (typical of the USA and Central Asia - loam and sandy loam);
• red (red-colored, stained with iron oxides soils of the desert areas of Afghanistan and Iran;
• white (salt marshes of some regions of Kalmykia, Turkmenistan and the Volga region).

Geography of storms

Dust storms occur in completely different places on the planet. The main habitat are semi-deserts and deserts of tropical and temperate climatic zones, with both earth hemispheres.

Usually the term "dust storm" is used when it occurs over loamy or clay soil. When it occurs in sandy deserts (for example, in the Sahara, Kyzylkum, Karakum, etc.), and, in addition to the smallest particles, the wind carries millions of tons of air and larger particles (sand), the term "sandstorm" is already used.

Dust storms often occur in the Balkhash region and the Aral Sea region (southern Kazakhstan), in the western part of Kazakhstan, on the Caspian coast, in Karakalpakstan and in Turkmenistan.

Where there are dusty Most often they are observed in the Astrakhan and Volgograd regions, in Tuva, Kalmykia, as well as in the Altai and Transbaikal territories.

During periods of prolonged drought, storms can develop (not every year) in the forest-steppe and steppe zones of Chita, Buryatia, Tuva, Novosibirsk, Orenburg, Samara, Voronezh, Rostov regions, Krasnodar, Stavropol territories, in Crimea, etc.

The main sources of dusty haze near the Arabian Sea are the peninsula and the Sahara. Less damage in these places is caused by the storms of Iran, Pakistan and India.

Chinese storms carry dust into the Pacific Ocean.

Environmental effects of dust storms

The described phenomena are capable of moving huge dunes and carrying large volumes of dust in such a way that the front can be represented as a dense and high wall of dust (up to 1.6 km.). Storms coming from the Sahara desert are known under the names Samum, Khamsin (Egypt and Israel) and Khabub (Sudan).

For the most part in the Sahara, storms occur in the Bodell Basin and at the junction of the borders of Mali, Mauritania and Algeria.

It should be noted that over the past 60-odd years the number of dusty Saharan storms has increased by about 10 times, which caused a significant decrease in the thickness of the surface soil layer in Chad, Niger, and Nigeria. For comparison, it can be noted that in Mauritania in the 60s of the last century, only two dust storms occurred, and today there are 80 storms per year.

Environmental scientists believe that an irresponsible attitude to the arid regions of the Earth, in particular, ignoring the crop rotation system, is steadily leading to an increase in desert areas and a change in the climatic state of planet Earth at the global level.

Ways to fight

Dust storms, like many others, do great harm. In order to reduce and even prevent their negative consequences, it is necessary to analyze the features of the localities - topography, microclimate, the direction of the prevailing winds here, and take appropriate measures that will reduce the wind speed at the earth's surface and increase the adhesion of soil particles.

To reduce the speed of the wind, certain events are held. Everywhere systems of wind-shelter backstage and forest belts are created. A considerable effect for increasing the adhesion of soil particles is provided by non-subsurface plowing, left stubble, crops of perennial grasses, strips of perennial grasses interspersed with crops of annual crops.

Some of the most famous sand and dust storms

For example, we offer you a list of the most famous sand and dust storms:

• In 525 BC e., according to the testimony of Herodotus, in the Sahara during the sandstorm killed 50 thousandth army of the king of Persia Cambyses.
• In 1928, in Ukraine, a terrible wind raised more than 15 million tons of black soil from an area of \u200b\u200b1 million km², the dust of which was transferred to the Carpathian region, Romania and Poland, where it settled.
• In 1983, a severe storm in northern Victoria in Australia covered the city of Melbourne.
• In the summer of 2007, a severe storm occurred in Karachi and in the territories of the provinces of Balochistan and Sindh, and heavy rains following it led to the death of about 200 people.
• In May 2008, 46 people were killed in a sand storm in Mongolia.
• In September 2015, a terrible “Sharav” (sandstorm) swept over a larger area of \u200b\u200bthe Middle East and North Africa. Israel, Egypt, Palestine, Lebanon, Jordan, Saudi Arabia and Syria were badly affected. There were human casualties.

In conclusion, a little about extraterrestrial dust storms

Martian dust storms occur as follows. Due to the large difference in temperature between the ice mass and warm air, strong winds appear on the outskirts of the southern polar cap of the planet Mars, raising huge clouds of dust of red-brown color. And here there are certain consequences. Scientists believe that the dust of Mars can play about the same role as the clouds of the earth. The atmosphere is heated due to the absorption of sunlight by dust.

Huge clouds of reddish reddish sand and dust clouds, raised from the surface of the earth by dry, hot and fast air currents, carry death. So, in 1805 a dust storm completely covered sand with a caravan of two thousand people and the same number of camels. The same story befell the Sahara in 525 BC. the legendary army of the Persian ruler Cambyses II: a terrible sandstorm halfway stopped the military expedition, killing about fifty thousand soldiers.

A sure sign that a sandstorm is approaching is the sudden silence when the wind stops blowing, and with it all sounds and rustles disappear. Instead, stuffiness intensifies, and with it, anxiety emerges on a subconscious level. And after a while, a rapidly growing cloud of black-crimson color appears on the horizon. The wind reappears and, gathering speed, raises dust and sand.

A sandstorm or, as it is also called, a dust storm is an atmospheric phenomenon when a strong wind moves large quantities of sand grains, soil particles or dust over long distances. The height of such a cloud can exceed a kilometer, while visibility inside it decreases to several tens of meters.

As these particles settle, the soil becomes reddish, yellowish or grayish (depending on the composition of the particles raised into the air). Despite the fact that dust storms appear mainly in the summer, in the absence of precipitation and rapid drying of the soil they occur in the winter.

Dust storms are formed mainly in desert or semi-desert regions (the Sahara Desert is especially famous for them), but sometimes due to drought it can also occur in the forest-steppe and forest regions of the planet. So, in April 2015, a sand storm hit Khmelnitsky, a city located in western Ukraine. The hurricane lasted about five minutes, visibility did not exceed ten meters, and the wind was so strong that it nearly pulled people and vehicles from bridges.

How the storm is formed

For a dust storm to occur, a dry surface of the soil and a wind with a speed exceeding 10 m / s are necessary (for example, in the Sahara its parameters often reach 50 m / s). Dust storms appear due to the turbulence (inhomogeneity) of air flows, which, when moving along an uneven surface, encountering obstacles, form air swirls. The faster the wind moves, the more dangerous it creates.

After the movement of air masses over loose soil particles increases, the adhesion between which is weakened due to the dryness of the soil (which is why storms of this type appear mainly in deserts), the grains of sand begin to vibrate, then jump, and as a result of repeated impacts turn into small ones dust.

Air swirls easily lift particles of sand or dust from the ground, while the temperature of the lower layers of air masses rises significantly: above the steppes - up to 1.5 km, over deserts - up to 2.5 km. After this, air mixes with dust particles, which tend to spread over the entire area of \u200b\u200bthe heated air.

While smaller particles fly extremely high above the earth's surface, large ones rise to a lower distance and fall quickly (if the wind is extremely strong, dust can travel thousands of kilometers). The strength of the wind during sandstorms is such that it is quite capable of shifting from the dune, and the sand raised by it will be like a huge cloud one and a half kilometers high.

In order for a dust storm to form, the soil must be dry: in the event of prolonged drought under the influence of strong winds, even particles of the upper layers of black earth soil can rise into the air (in this case, a “black storm” is formed), and travel long distances.

So, at the end of the twenties of the last century, in the forest-steppe and steppe forests of Ukraine, a sudden dust storm raised more than 15 million tons of chernozem (with the cloud height being 750 m) and transported them thousands of kilometers to the side. Some dust settled in the Carpathian region, Poland and Romania, as a result of which the fertile soil layer in the affected regions (about 1 million km2) decreased by 10-15 cm.

How long does the phenomenon last

The duration of sandstorms is usually thirty minutes to four hours. At the same time, short-term dust storms are characterized by a slight deterioration in visibility: the terrain is visible up to four, and sometimes up to 10 kilometers.

Among short-term there are also such dust storms during which visibility is limited to two tens of meters.

A dust storm always appears almost unexpectedly: a storm of wind will rise in good weather, as a result of which the speed of air flows increases, picking up and raising dust particles into the air.

True, poor visibility does not last long, despite the fact that the wind speed is increasing at this time. You can find out that a dust storm is approaching by the gray misty strip of the veil that appears under the cumulonimbus clouds when they are located near the horizon.

There are also long sandstorms:

• Some dust storms are characterized only by a partial deterioration in visibility, up to four kilometers (although, in time, these dust storms are the longest, since they can last several days).
• For others, the visibility is limited to several meters at the initial stage of development, after which it clears up to one kilometer. But these sandstorms last no more than four hours.

Storms of the Sahara

Many sandstorms originate in the largest desert in the world, the Sahara, where Mauritania, Mali and Algeria border each other. Over the past half century, the number of sandstorms in the Sahara has increased tenfold (about eighty storms sweep through Mauritania alone in a year).

There is so much raised Sahara sand that a huge amount of sand particles are transported across the Atlantic Ocean. This situation is possible due to the fact that when dust and sand move over the desert, they continue to heat up together with the air, after which, when they are above the ocean, they pass under a colder and wetter air stream. The difference in temperature between the layers of air leads to the fact that they do not mix with each other, allowing dusty warm air to cross the ocean.

Despite the fact that sandstorms cause many negative consequences (they destroy the fertile soil layer, adversely affect the respiratory system of living organisms), dust raised into the air brings benefits. For example, the Sahara dust storms supply the moist equatorial forests of Central and South America with a huge amount of mineral fertilizers, and the ocean receives the missing part of iron. At the same time, the dust raised in Hawaii makes it possible to grow banana trees.

What to do if caught in a storm

Having noticed the first signs of an approaching storm, you need to immediately stop: continue to move uselessly and an extra waste of energy, especially since a sandstorm rarely lasts more than four hours. Even if the wind does not calm down for about two to three days, it is better to wait in one place and not go anywhere. Therefore, all supplies of water and food must be kept close to you (especially water, otherwise complete dehydration of the body is ensured, and this always leads to death).

Having stopped, you must immediately begin to seek shelter. It can be a large stone, a boulder, a tree near which you need to lie on the leeward side and completely, with your head, wrap yourself in matter. If there is an opportunity to hide in a car, it must be put in such a way that the wind does not blow in the door.

In the worst case, if no shelter is nearby, you need to lie on the ground and cover your head with clothing (Bedouins in such cases dig something like a trench). It should be borne in mind that when a sandstorm flies, the air temperature at that moment will be about fifty degrees, which can lead to loss of consciousness. Breathing while tons of sand are flying overhead, you need only through a handkerchief, otherwise the smallest particles will fall into the respiratory tract.

“The warriors of the Persian king Cambyses struggled forward. Around, as far as the eye could see, there were ridges of sand.

Having conquered in 525 BC Egypt, the lord of the Persians did not get along with his priests. The attendants of the temple of the god Amon prophesied his quick death, and Cambyses decided to punish them. The fifty thousandth army was sent on a campaign. Her path ran through the Libyan desert. Seven days later, the Persians reached the great oasis of Kharg, and then ... disappeared without a trace.

Talking about this, the famous ancient Greek historian Herodotus adds: "Apparently, the warriors of Cambyses were killed by a severe sandstorm."

There are many descriptions of sandstorms in deserts. Nowadays, when the desert is crossed by roads and airways run in all directions above them, death on the great caravan routes no longer threatens travelers. But before ...

An hour or half an hour before the merciless storm rises, the bright sun dims, is covered with a muddy veil. A small dark cloud appears on the horizon. It grows rapidly, covering the blue sky. Here came the first fierce rush of a hot, spiky wind. And in a minute the day fades. Clouds of burning sand mercilessly cut all living things, cover the midday sun. In the howling and whistling of the wind all other sounds disappear.

“People and animals were suffocating. It lacked the very air, which seemed to rise up and fly away with a reddish, brown haze, already completely covering the horizon. My heart was beating terribly, my head hurt mercilessly, my mouth and throat were dry, and it seemed to me that another hour - and the death of suffocation by sand was inevitable. " So the Russian traveler of the last century A.V. Eliseev describes a storm in the deserts of North Africa.

Sandstorms - Samums - have long been fanned by gloomy fame. No wonder they bear this name: samum - means poisonous, poisoned. He really ruined entire caravans. So, in 1805, according to the testimony of many authors, the sumum covered sand with two thousand people and one thousand eight hundred camels. And quite possibly, the same storm once destroyed Cambyses army.

It happens that the testimonies of people who have passed the test of the elements sin by exaggeration. However, no doubt: the sumum is very dangerous. Fine sand dust, which is raised by a strong wind, penetrates the ears, eyes, nasopharynx, and lungs. Streams of dry air inflame the skin, cause excruciating thirst. Saving lives, people lie down on the ground and tightly cover their heads with clothes. It happens that from suffocation and high temperature, which often reaches fifty degrees, they lose consciousness.

Here is an excerpt from travel notes of the Hungarian explorer of Central Asia A. Wambury: “In the morning we stopped at the station bearing the pretty name Adamkirilgan (the place of death of people), and we just had to look around to see that this name was given for good reason. Imagine a sea of \u200b\u200bsand going in all directions, as far as the eye can see, torn by the winds and representing, on the one hand, a series of high hills lying in ridges, like waves, and on the other - like the surface of a lake, even and covered with wrinkles of ripples. Not a single bird in the air, not a single animal on the earth, not even a worm or a grasshopper. No signs of life, except for bones whitened in the sun, collected by each passerby and laid in the path to make it easier to go ...

Despite the tormenting heat, we were forced to walk day and night for five to six hours in a row.

We had to hurry: the sooner we get out of the sand, the less danger there is under the tebbad (feverish wind), which can fill us with sand if it stays on the dunes ...

When we approached the hills, the caravan towers and guides pointed us towards an approaching cloud of dust, warning us to dismount. Our poor camels, more experienced than ourselves, already felt the approach of the tabbad, roared desperately and fell to their knees, holding their heads on the ground, and tried to bury them in the sand. Behind them, as if under cover, we hid. The wind came with a dull noise and soon covered us with a layer of sand. The first grains of sand that touched my skin gave the impression of a fiery rain ... "

This unpleasant meeting among travelers occurred between Bukhara and Khiva.

Many desert storms owe their birth to passing cyclones, which also affect the desert. These are cyclonic storms. There is another reason: in deserts during the hot season, atmospheric pressure decreases. Hot sands greatly heat the air at the surface of the earth. As a result, it rises, and flows of colder dense air rush in its place with very high speeds. Small local cyclones form, generating sandstorms.

Very peculiar air currents, reaching great power, are observed in the mountains of the Pamirs. Their reason is the extremely sharp difference between the surface temperature of the earth, strongly heated by the bright mountain sun, and the temperature of the upper, very cold layers of air. The winds here reach a special intensity in the middle of the day, and often turn into hurricanes that raise sandstorms. And in the evening they usually subside.

In some areas of the Pamirs, such winds are so strong that even now, caravans are still dying there.

One of the valleys here is called the Death Valley, it is dotted with bones of dead animals.