Wind (The horizontal component of the air movement relative to the earth's surface) is characterized by direction and speed.
Wind speed It is measured in meters per second (m / s), kilometers per hour (km / h), nodes or fabala points (wind power). The node is a marine velocity measure, 1 sea mile per hour, approximately 1 node is 0.5 m / s. Bafort's scale (Francis Beaufort, 1774-1875) was created in 1805.

Direction of the wind (where it blows) is indicated either in Rumbach (at a 16-rumbic scale, for example, the north wind - C, northeast - sv, etc.), or in the corners (relative to the meridian, north - 360 ° or 0 °, East - 90 °, South - 180 °, west - 270 °), Fig. one.

Wind name	Speed, m / s	Speed, km / h	Knots	Wind power, points	Wind effect
Calm	0	0	0	0	Smoke rises vertically, trees leaves still. Mirror smooth sea
Quiet	1	4	1-2	1	Smoke deviates from the vertical direction, the sea light ripples, there is no foam on the ridges. Wave height to 0.1 m
Easy	2-3	7-10	3-6	2	The wind is felt face, leaves rustle, the fluger begins to move, the sea short waves with a maximum height up to 0.3 m
Weak	4-5	14-18	7-10	3	Leaves and thin branches of trees pegs, disgusted light flags, light excitement on the water, occasionally small "lambs" are formed. Average wave height 0.6 m
Moderate	6-7	22-25	11-14	4	The wind raises dust, paper; Thin branches of trees are swinging, white "lamb" on the sea are visible in many places. Maximum wave height to 1.5 m
Fresh	8-9	29-32	15-18	5	The branches and subtle trunks of trees are swinging, the wind is felt by hand, white "lames" are visible on the water. Maximum wave height 2.5 m, average - 2 m
Strong	10-12	36-43	19-24	6	Thick buccias are swinging, the thin trees are bent, the telephone wires are buzzing, umbrellas are used with difficulty; White foam ridges occupy significant areas, water dust is formed. Maximum wave height - up to 4 m, average - 3 m
Strong	13-15	47-54	25-30	7	Trees trunks are swinging, large branches are rushing, it is difficult to go against the wind, the ridges of the waves are drunk by the wind. Maximum wave height to 5.5 m
Very strong	16-18	58-61	31-36	8	Thin and dry buccias break, it is impossible to speak in the wind, it is very difficult to go against the wind. Strong excitement to the sea. Maximum wave height to 7.5 m, average - 5.5 m
Storm	19-21	68-76	37-42	9	Big trees bent, the wind breaks off the roofs, very strong excitement at sea, high waves (maximum height - 10 m, average - 7 m)
Heavy storm	22-25	79-90	43-49	10	There is rare on land. Significant destruction of buildings, the wind shakes the trees and pulls them down with the root, the surface of the sea is white from foam, a strong crash of the waves is similar to shocks, very high waves (maximum height - 12.5 m, average - 9 m)
Cruel storm	26-29	94-104	50-56	11	Observed very rarely. Accompanied by destruction on large spaces. At sea Exceptionally high waves (maximum height - up to 16 m, average - 11.5 m), units of small sizes are hiding out of sight
Hurricane	More than 29.	More than 104.	More than 56.	12	Serious destruction of capital buildings

The main value characterizing the strength of the wind is its speed. The magnitude of the wind speed is determined by the distance in meters passing by it for 1 sec. For example, if in 20 seconds. The wind passed the distance of 160 m, then its speed V for this period of time was equal to:

Wind speed is distinguished by great impermanence: it changes not only for a long time, but also in short periods of time (within an hour, minutes, and even seconds) for a large amount. FIG. 1 Dana curve showing a change in wind speed for 6 minutes. From this curve, you can conclude that the wind is moving with a pulsating speed.

FIG. 1. Wind speed characteristic.

Wind speeds observed in short periods of time from a few seconds to 5 minutes are called instant or valid. The speed of wind, obtained as the average arithmetic of instantaneous speeds, is called average wind speeds. If you fold the measured wind speeds during the day and divided by the number of measurements, then the average daily wind speed will be obtained. If you add the average daily wind speed for the entire month and divide this amount for the number of days of the month, we will get the average monthly wind speed. Folding the average monthly speeds and dividing the amount for twelve months, we obtain the average annual wind speed. An interesting student project. Famous people of Russia. Very big base surnames and all for free.
Wind velocities are measured using instruments called anemometers. The simplest anemometer that allows you to determine instantaneous wind speeds and called the simplest fluger-anemometer is shown in FIG. 2.

FIG. 2. The simplest fluger anemometer.

It consists of a metal board, rocking near the horizontal axis A, fixed on the vertical rack b. On the side of the board on the same axis A sector in, with eight pins. On the rack B below the sector, the vane r is fixed, which all the time installs the plane on the wind. Under the action of the latter, the board is deflected and passes past the pins, each of which indicates a certain wind speed. The rack B with a fluger G is rotated by the EO sleeve d, in which 4 long rods are fixed in the horizontal plane, indicating the main countries of the world: north, south, east and west, and between them 4 short, indicating northeast, north-west, south Food and Southwest. Thus, it is also possible to determine the speed and direction of the wind at the same time using the anemometer.
The values \u200b\u200bof wind velocities corresponding to each pin of the sector B are shown in Table. one.

The average wind speeds for short and prolonged intervals are conveniently determined by the metrpribor plant anemometer (Fig. 3). It consists of crossbars with hemispheres, put on the axis that is in engaging with a toothed transmission placed in a box with a dial.

FIG. 3. Plant anemometer "Metrpribor".

The gear axes are bred on the dial and at their ends have arrows showing the path traveled by the wind during the period of time. By dividing the number shown by the arrows on the dial, by the number of seconds during which the anemometer rotated, we obtain the wind speed per second for the observed period. For example, before the start of observation, the arrow on the dial showed 7170 m, a no expiration of 2 minutes, equal to 120 seconds, the arrows showed 7650 m. Consequently, the average wind speed during the interval of the time in 2 minutes. It was equal to:

If there are no indicated devices, the wind speed can be determined by approximately external signsobserved in nature (see Table 2).

Scale for determining speed, strength and names of wind (Bafort scale)

Distinguish smoothed Speed \u200b\u200bfor some short period of time and instant, speed at the moment time. Speed \u200b\u200bis measured by anemometer using the Wilde board.

The greatest average annual wind speed (22 m / s) was observed on the coast of Antarctica. The average daily rate, sometimes reaches 44 m / s, and in some points reaches 90 m / s.

Wind speed has a daily move. It is close to the daily movement of the temperature. The maximum speed in the surface layer (100 m - in the summer, 50 m - winter) is observed at 13-14 hours, the minimum speed is at night. In the higher layers of the atmosphere, the daily course of the speed is reverse. This is due to the change in the intensity of the vertical exchange in the atmosphere during the day. Intensive vertical exchange difficulties the horizontal movement of air masses difficult. At night, this obstacle is not and VM move in the direction of the Baric gradient.

Wind speed depends on the pressure difference and is directly proportional to it: the greater the pressure difference (horizontal baric gradient), the greater the wind speed. The average multi-year wind speed in the earth's surface is 4-9 m / s, rare more than 15 m / s. In storms and hurricanes ( moderate breadth) - up to 30 m / s, in gusts up to 60 m / s. In tropical hurricane wind speed reach up to 65 m / s, and 120 m / s gusts can reach.

Devices with which the wind speed is measured, called anemometers.Most anemometers are built on the principle of windmill. For example, the Fuss Anemometer has at the top of four hemispheres (cups) facing one way (Fig. 75).

This system of hemispheres rotates near the vertical axis, and the number of revolutions is marked with a meter. The device is exhibited by the wind, and when the "Mill of Hemispheres" acquires more or less permanent speedThe counter is turned on at exactly a certain time. According to the plate on which the number of revolutions is indicated for each wind speed, and the speed of the results is determined by the speed. There are more complex devices that have a device for automatically record direction and wind speed. Also, simple devices are also used for which the direction and wind force can be determined at the same time. An example of such an appliance can serve as Wilde Wilde vilde vildren in all meteorological stations.

The wind direction is determined by that side of the horizon with which the wind blows. For its designation, eight main directions (Rumbs) are applied: C, SZ, Z, YUZ, YU, YUV, B, SV. The direction depends on the distribution of pressure and from the deflecting action of the rotation of the Earth.

Rose of Wind.Winds like other phenomena in the life of the atmosphere are prone to strong changes. Therefore, it is necessary to find the average values.

To determine the dominant directions of winds for one or another period of time, they are applied as follows. Speak from some point eight main directions, or rumbers, and on each on a certain scale, the repeatability of the winds are deposited. On the resulting image known called roses winds,the dominant winds are clearly visible (Fig. 76).

The wind force depends on its speed and shows which dynamic pressure has air flow to any surface. Wind power is measured in kilograms per square meter (kg / m2).

Wind structure.The wind cannot be imagined with a homogeneous air flow having the same direction and the same speed in the entire mass. Observations show that the wind blows a pusty, as if individual jerseks, sometimes pokes, then again acquires the former speed. At the same time, the direction of the wind is also subject to change. Observations produced in higher air layers show that it decreases with height. It is also noticed that at various times of the year and even at various hours of the day of the breedness of the wind unenkimak. The greatest pivyness is observed in the spring. During the day, the greatest wind attenuation - at night. The impact of the wind depends on the nature of the earth's surface: the more irregularities, the greater the gust and the opposite.

Causes of winds.Air remains alone until the pressure in this section of the atmosphere is distributed more or less evenly. But it costs the pressure in any area to increase or decrease, as the air will flow from the place of greater pressure towards the smaller. The emerging movement of the mass of air will continue until the pressure difference is aligned and equilibrium will not be established.

Sustainable equilibrium in the atmosphere is almost never observed, therefore the winds relate to the most frequently repeated phenomena in nature.

The reasons that violate the equilibrium of the atmosphere, a lot. But one of the first reasons that generates the pressure difference is the difference in temperatures. We will analyze the simplest case.

We have the surface of the sea and the coastal part of the sushi. In the afternoon, the sushi surface is heated faster than the sea surface. Due to this, the lower layer of air over the land is expanding more than above the sea (Fig. 77, i). As a result, the top is the same as the air flow from the warmer region to the coolest (Fig. 77, II).

Due to the fact that part of the air from the warm region flowed (at the top) towards the cold, the pressure within the cold region will increase, and within the warm region will decrease. As a result, the air current occurs now in the lower layer of the atmosphere from the cold area to warm (in our case from the sea to land) (Fig. 77, III).

Similar air flows usually arise on the sea coast or on the shores of large lakes and are called brimes.In the example we, the daily breeze. At night, the picture is completely reverse, for the surface of the sushi, cooling the fastest surface of the sea, becomes colder. As a result, the air will flow toward sushi in the upper layers of the atmosphere, and in the lower layers towards the sea (night breeze).

Air rise from the warm area and lowering in the cold combines the upper and lower flow and creates closed circulation (Fig. 78). In these closed cyphans, the vertical parts of the path are usually very small, horizontal, on the contrary, can reach huge sizes.

Causes of different wind speed.It goes without saying that the wind speed should depend on the pressure gradient (i.e. it is determined primarily by the difference in pressures per unit distance). If, in addition to the force due to the gradient, there were no other forces on the mass of air, the air would move evenly-accelerated. However, this does not work, because there are a lot of reasons that slow down the air movement. This is primarily friction.

Throw friction of two types: 1) friction of the surface layer of air o earth surface and 2) friction arising within the moving air itself.

The first is in direct dependence on the nature of the surface. For example, the aqueous surface and the flat steppe create the smallest friction. Under these conditions, wind speed always increases significantly. The surface with irregularities creates large obstacles to moving air, which leads to a decrease in wind speed. Especially strongly lower wind speed urban buildings and forest plantations (Fig. 79).

Observations produced in the forest showed that already in 50 m.from the edge, the wind speed decreases to 60-70% of the initial speed, 100 m.up to 7%, 200 m.up to 2-3%.

Friction that occurs between the adjacent layers of the moving air mass, is called internal friction.Internal friction causes traffic from one layer to another. The surface layer of air as a result of friction about the earth's surface has the most slower movement. The above layer, in contact with the moving lower layer, also slows down its movement, but to a much lesser extent. An even smaller impact is experiencing the next layer, etc. As a result, the speed of air movement is gradually increasing.

Direction of winds.If a most important cause The wind is the difference in pressures, the wind must blow from the larger pressure area into the lower pressure region in the direction perpendicular to the ed. However, this does not happen. In fact (as it is established by observations), the wind blows mainly along the isobar and only slightly deflects towards low pressure. This is due to the deflecting effect of the Earth's rotation. At one time, we have already said that any moving body under the influence of the Earth's rotation is deviated from its initial path in the northern hemisphere to the right, and in the southern left. They also said that the deviating power in the direction of the equator to the poles increases. It is absolutely clear that the movement of air, which arose due to the difference in pressures, immediately begins to experience the influence of this deflecting force. By itself, this power is small. But due to the continuity of its action in the end, the effect is very large. If there were no friction and other influences, then as a result of a continuously acting deviation, the wind could describe a closed curve close to the circle. In fact, due to the influence of various reasons for such a deviation, it does not work, but nevertheless it is still quite significantly. It is enough to indicate at least on the trade winds, the direction of which, with the fixed state of the Earth, would be to coincide with the direction of the meridian. Meanwhile, their direction in the northern hemisphere northeast, in South - Southeast, and in moderate latitudes, where the rejection force is even more, the wind blowing from the south to the north acquires the Western-South-West direction (in the northern hemisphere).

The main wind systems.Winds observed on the earth's surface are very diverse. Depending on the reasons that generate this variety, we divide them for three large groups. To the first group, we will draw winds, the reasons for which depend mainly on the local conditions, to the second - winds caused by the total circulation of the atmosphere, and the third - the winds of cyclones and anticyclones. Let's start our consideration from the simplest winds, the reasons for which depend mainly on local conditions. Here we attribute breezes, various mountain, valley, steppe and desert winds, as well as monsoon winds that are already dependent only from local reasons, but also from total circulation Atmosphere.

Winds are extremely diverse by origin, nature and value. So, in moderate latitudes where Western transfer dominates, winds prevail western directions (SZ, Z, UZ). These areas occupy extensive spaces - from about 30 to 60 ° in each hemisphere. In the polar regions, the winds blow from the poles to the zones of reduced pressure of moderate latitudes. In these areas prevail northeastern winds In the Arctic and southeast in Antarctica. At the same time, the southeastern winds of the Antarctic, in contrast to the arctic, more stable and have high speeds.

The wind as a phenomenon of nature is known to everyone from early childhood. He pleases the fresh blow to a hot day, drives the ships by the sea, and the trees can be bend, and break the roofs at home. The main characteristics that the wind define are its speed and direction.

From a scientific point of view, the wind is called the movement of air masses in a horizontal plane. Such a move occurs because there is a difference in atmospheric pressure and heat between two points. Air moves from high pressure areas in those areas where the pressure level is below. As a result, the wind occurs.

Wind characteristics

In order to characterize the wind, use two basic parameters: direction and speed (strength). The direction is determined by the side of the horizon with which it blows. It may be indicated in Rumbach, in accordance with the 16-rumbic scale. According to her, the wind can be the northern, southeast, north-north-western and so on. It can also be measured in degrees, relative to the Meridian line. On this scale, the North is defined as 0 or 360 degrees, East - 90 degrees, west - 270 degrees, and south - 180 degrees. In turn, measured in meters per second or in nodes. The node is approximately 0.5 kilometers per hour. Wind power is also measured in points, according to the Beaufort scale.

In accordance with which the strength of the wind is determined

This scale was introduced into appeal in 1805. And in 1963, the World Meteorological Association adopted a gradation that acts to this day. Within its frames, 0 points correspond to the calm, in which smoke will rise vertically, and the leaves on the trees remain motionless. The strength of the wind of 4 points corresponds to a temperate wind, in which small waves are formed on the surface of the water, thin branches and leaves on the trees can be squeezed. 9 points correspond to a storm wind, in which even large trees can be labeled, tile from the roofs, climb high waves on the sea. And the maximum strength of the wind in accordance with this scale, namely, 12 points, falls on a hurricane. This is the phenomenon of nature, in which the wind causes serious permits, even capital buildings can be collapsed.

Using wind power

Wind power is widely used in energy as one of the replenish natural sources. From time immemorial, humanity used this resource. It is enough to remember or sailing vessels. Windmills, with which wind is converted to further use, are widely used in places for which constant strong winds are characterized. Of the various applications of such a phenomenon as the strength of the wind, it is also worth mentioning the aerodynamic pipe.

Wind - a natural phenomenonwhich can enjoy or destruction, as well as be useful for humanity. And its specific action depends on how much the strength (or speed) of the wind will be.

Meteorological dangerous phenomena - Natural processes and phenomena arising in the atmosphere under the action of various natural factors or their combinations that provide or can affect the impact on people, farm animals and plants, economy objects and the environment.

Wind -this movement of air is parallel to the earth's surface resulting from an uneven heat distribution and atmospheric pressure and directed from the high pressure zone into the low pressure zone.

The wind is characterized by:
1. The direction of the wind - is determined by the azimut of the side of the horizon, from where
It blows, and is measured in degrees.
2. Wind speed - measured in meters per second (m / s; km / h; miles / hour)
(1 mile \u003d 1609 km; 1 sea mile \u003d 1853 km).
3. The strength of the wind is measured by the pressure, which it has 1 m2 of the surface. Wind power changes almost proportional speed,
Therefore, wind power is often assessed not by pressure, but by speed, which simplifies the perception and understanding of these quantities.

For the designation of wind movement, many words are used: a tornado, a storm, a hurricane, a storm, typhoon, cyclone and a lot of local names. To systematize them, all over the world enjoy beaufort scalewhich allows you to quite accurately appreciate the strength of the wind in points (from 0 to 12) in its action on ground items or to excitement into the sea. This scale is also convenient because it allows the signs described in it quite accurately determine the wind speed without appliances.

Beaufort scale (Table 1)

Point Befort	Verbal definition wind power	Wind speed, m / s (km / h)	Wind action on land
			On the land	On the sea
		0,0 – 0,2 (0,00-0,72)	Calm. Smoke rises vertically	Mirror smooth sea
	Quiet breeze	0,3 –1,5 (1,08-5,40)	The direction of the wind is noticeable at the following smoke,	Ripples, foam on the ridges
	Light breeze	1,6 – 3,3 5,76-11,88)	Wind movement feels face, rustle leaves, moves vane	Short waves, ridges do not overturn and seem to be vitreous
	Weak breeze	3,4 – 5,4 (12,24-19,44)	Leaves and thin branches of trees pegs, wind waves top flags	Short well-pronounced waves. Combs, tilting, form foam, occasionally small white lambs are formed.
	Moderate breeze	5,5 –7,9 (19,8-28,44)	The wind raises dust and papers, drives thin branches of trees	Waves elongated, white whiskers are visible in many places.
	Fresh breeze	8,0 –10,7 (28,80-38,52)	Thin trunks of trees are swinging, waves appear on the water with ridges	Well developed long, but not very large waves, white lambs are visible everywhere.
	Strong breeze	10,8 – 13,8 (38,88-49,68)	Thread bunches of trees are swinging, buzzles	Large waves begin to form. White foam ridges occupy significant areas.
	Strong wind	13,9 – 17,1 (50,04-61,56)	Trees trunks are swinging, it's hard to go against the wind	Waves are prayer, the ridges are broken, foam lies with strips in the wind
	Very strong wind ( storm)	17,2 – 20,7 (61,92-74,52)	The wind breaks the bitch of the trees, go against the wind is very difficult	Moderately tall, long waves. At the edges of the ridges begin to take the splashes. Foam strips fall along the wind.
	Storm (strong storm)	20,8 –24,4 (74,88-87,84)	Minor damage; The wind breaks down the smoke caps and tiles	High waves. Foam is widely dense stripes falling around the wind. Combs of waves tip over and scattered into splashes.
	Heavy storm (Full storm)	24,5 –28,4 (88,2-102,2)	Significant destruction of buildings, trees break down with the root. There is rare on land	Very high waves with long bending Down crests. The foam swelled with the wind with large flakes in the form of thick strips. The surface of the sea is white from foam. The crash of the waves is like shocks. Visibility is bad.
	Cruel storm (tough storm)	28,5 – 32,6 (102,6-117,3)	Large destruction at a significant space. On land is very rare	Exceptionally high waves. Courts are hidden from the view. The sea is all covered with long foam flakes. The edges of the waves are blown away in a foam. Visibility is bad.
		32.7 or more (117.7 or more)	Heavy items are transferred to the wind at considerable distances.	The air is filled with foam and splashes. The sea is all covered with foam stripes. Very bad visibility.

Breeze (from easy to strong breeze) Sailors call the wind having a speed from 4 to 31 miles / hour. In terms of kilometers (coefficient of 1,6) it will be 6.4-50 km / h

The speed and direction of the wind determine the weather and climate.

Strong winds, significant atmospheric pressure drops and a large number of Precipitation cause dangerous atmospheric vortices (cyclones, storms, squalls, hurricanes) that can cause destruction and human sacrifices.

Cyclone is the general name of the vortices with reduced pressure in the center.

Anticyclone is an area increased pressure In the atmosphere with a maximum in the center. In the northern hemisphere, the winds in the anticyclone are configured counterclockwise, and in the southern - clockwise, in the cyclone, the wind movement is reverse.

Hurricane - the wind of the destructive strength and significant duration, the speed of which is equal to or exceeds 32.7 m / s (12 points on the Bafort scale), which is equivalent to 117 km / h (Table 1).
In half cases, the wind speed with a hurricane exceeds 35 m / s, reaching up to 40-60 m / s, and sometimes up to 100 m / s.

Depending on the wind speed of hurricanes are classified into three types:
- Hurricane (32 m / s or more)
- Strong hurricane (39.2 m / s or more)
- brutal hurricane (48.6 m / s or more).

The cause of such hurricane windsis the emergence, as a rule, on the collision line of the fronts of warm and cold air masses, powerful cyclones with a sharp pressure drop from the periphery to the center and with the creation of a vortex air flow moving in the lower layers (3-5 km) by spirals to the middle and up, In the northern hemisphere - counterclockwise.

Such cyclones, depending on the place of their occurrence and structure, is customary to:
- tropical cyclonesthey are found over warm tropical oceans, in the formation stage usually moves to the West, and after the end of the formation bend to the poles.
Tropical cyclone who has achieved unusual power is called hurricane if it is born in the Atlantic Ocean and adjacent to the seas; typhoon - in Pacific Ocean or his seas; cyclone - in the Indian Ocean region.
Cyclones of moderate breadthcan be formed both above the land and above the water. Usually they move from west to east. Characteristic feature Such cyclones are their big "dryness". The amount of precipitation during their passage is significantly less than in the zone of tropical cyclones.
The European mainland affects both tropical hurricanes, nascent in the Central Atlantic and cyclones of moderate latitudes.
Storm – a variety of hurricane, but has a smaller wind speed 15-31
m / s.

Storm duration - from several hours to several days, width from dozens to several hundred kilometers.
Storms are divided:

2. Stream storm – These are local phenomena of small spread. They are weaker than the vortex storms. They are divided:
- Stock -the air flow moves along the slope from top to bottom.
- joys - Characterized by the fact that the air flow is moving horizontally or up the slope.
Storm storms are most often between chains of mountains connecting valleys.
Depending on the color of the particles involved in motion, the black, red, yellow-red and white storms are distinguished.
Depending on the wind speed, the storm are classified:
- Storm 20 m / s and more
- Strong storm 26 m / s and more
- Tough storm 30.5 m / s or more.

Squall – A sharp short-term amplification of the wind to 20-30 m / s and above, accompanied by a change in its direction associated with convective processes. Despite the short-term Shkvalov, they can lead to disastrous consequences. The squalls in most cases are associated with cucco-rain (thunderstorm) clouds or local convection, or a cold front. The flurry is usually associated with storm sediments and thunderstorms, sometimes with a hail. The atmospheric pressure during the squall increases dramatically due to the rapid precipitation, and then falls again.

If possible, limiting the exposure zone, all listed natural disasters belong to non-silicizes.

Hazardous consequences of hurricanes and storms.

Hurricanes are one of the most powerful forces The elements and in their indulgence are not inferior to such terrible natural disasters like an earthquake. This is explained by the fact that hurricanes carry colossal energy. Its amount allocated by the average power of the hurricane for 1 hour is equal to the energy of the nuclear explosion of 36 MT. Over the day, the amount of energy, which would have enough for semi-annual providing electricity of such a country as the United States. And in two weeks (the average duration of the existence of a hurricane) such a hurricane energizes energy equal to the energy of the Bratsk HPP, which it can work out for 26 thousand years. Very high is the pressure in the hurricane zone. It reaches several hundred kilograms per square meter of a fixed surface, located perpendicular to the direction of wind movement.

Hurricane wind destroys Durable and demolfates light buildings, empties the seeded fields, breaks the wires and pillars of power lines and communications, damages the transport highways and bridges, breaks and pulls the trees with roots, damages and dries the court, causes accidents on utility and energy networks, in production. There are cases when the hurricane wind destroyed the dam and dam, which led to large floods, discharged from the rails of the train, drove off the bridges from the support, shaved the factory pipes, threw the ships to the land. Often hurricanes accompany the strong shower, which are the most dangerous of the Hurricane itself, since they are the cause of the village streams and landslides.

The size of hurricanes are different. Usually, the width of the hurricane take the width of the zone of catastrophic destruction. Often, the territory of winds of storm strength is added to this zone with relatively small destruction. Then the width of the hurricane is measured by hundreds of kilometers, reaching sometimes 1000 km. For typhoons, the strip of destruction is usually 15-45 km. The average duration of the hurricane is 9-12 days. Hurricanes arise at any time of the year, but most often from July to October. In the remaining 8 months, they are rare, their ways are short.

The damage caused by the hurricane is determined by the whole complex of various factors, including terrain relief, degree of development and strength of buildings, the nature of vegetation, the presence in the zone of its operation of the population and animals, the time of the year, conducted by preventive measures and a number of other circumstances, the main of which is High-speed air flow Q, proportional to density atmospheric air On the square speed of the air flow q \u003d 0,5pv 2.

According to the construction standards and rules, the maximum normative value of the wind pressure is q \u003d 0.85 kPa, which at the density of the air R \u003d 1.22 kg / m3 corresponds to the wind speed.

For comparison, the calculated values \u200b\u200bof the high-speed pressure used to design nuclear power plants for the Caribbean area are: for category I categories - 3.44 kPa, II and III - 1.75 kPa and open settings - 1.15 kPa.

Every year about a hundred powerful hurricanes march ground Shar., causing destruction and often withdrawing human life (Table 2). June 23, 1997 over for the most part The Brest and Minsk regions swept the hurricane, as a result of which 4 people died, 50 were injured. 229 were de-energized in the Brest region settlements1071 substation was disabled, the roofs are torn with 10-80% of residential buildings in more than 100 settlements, up to 60% of agricultural buildings were destroyed. In the Minsk region, 1410 settlements were de-energized, hundreds of houses were damaged. Stalls and twisted trees in forests and forest parks. At the end of December 1999, Belarus suffered from both a hurricane wind, which was swept over Europe. There were broken power lines, many settlements are de-energized. A total of 70 districts and more than 1,500 settlements suffered from the hurricane. Only in the Grodno region, 325 transformer substations were faced, in Mogilev even more - 665.

table 2
The consequences of the impact of some hurricanes

Catastrophe place year	The number of dead	Number of wounded	Related phenomena
Haiti, 1963.		Not fixed
		Not fixed
Honduras, 1974.		Not fixed
Australia, 1974.
Sri Lanka, 1978		Not fixed
Dominican Republic, 1979
		Not fixed
Indochytay, 1981.		Not fixed	Flood
Bangladesh, 1985.		Not fixed	Flood

Tornado (tornado) - The vortex movement of air spreading in the form of a giant black pillar with a diameter to hundreds of meters, inside which is observed an air discharge, where various items are tightened.

Mortal arise both over the aquatic surface and above the land, much more often than hurricanes. Very often they are accompanied by thunderstorms, hail and shoes. Air rotation speed in the dust pole reaches 50-300 m / s or more. During its existence, it can pass the way to 600 km - on the area of \u200b\u200bthe area of \u200b\u200bthe width of several hundred meters, and sometimes to several kilometers, where the destruction arise. The air in the post climbs the spiral and delays dust, water, objects, people.
Dangerous factors:the construction fell in the tornadow due to the discharge in the air post is destroyed from the air pressure from the inside. He pulls out the trees with roots, overturns cars, trains, raises in the air at home, etc.

Tornado in the Republic of Belarus arose in 1859, 1927 and 1956.