Classification of wind force, sea waves and visibility. Storms, squalls, hurricanes, their characteristics, damaging factors Normal wind speed

Each natural phenomenon, which has different degrees of severity, is usually evaluated in accordance with certain criteria. Especially if information about it must be transmitted quickly and accurately. For wind strength, the Beaufort scale has become a single international benchmark.

Developed by the British rear admiral, a native of Ireland, Francis Beaufort (stress falls on the second syllable) in 1806, the system, improved in 1926 by adding information about the equivalence of wind strength in points of its specific speed, allows you to fully and accurately characterize this atmospheric process, while remaining relevant and to this day.

What is wind?

Wind is the movement of air masses parallel to the surface of the planet (horizontally above it). This mechanism is caused by pressure difference. The direction of movement always comes from the higher area.

To describe the wind, it is customary to use the following characteristics:

• speed (measured in meters per second, kilometers per hour, knots and points);
• wind strength (in points and m.s. - meters per second, the ratio is approximately 1:2);
• direction (according to cardinal directions).

The first two parameters are closely related. They can be mutually denoted by each other's units of measurement.

The direction of the wind is determined by the side of the world from where the movement began (from the north - the north wind, etc.). Velocity determines the pressure gradient.

Baric gradient (otherwise - barometric gradient) - change in atmospheric pressure per unit distance along the normal to a surface of equal pressure (isobaric surface) in the direction of decreasing pressure. In meteorology, the horizontal barometric gradient is usually used, that is, its horizontal component (Great Soviet Encyclopedia).

The speed and strength of the wind cannot be separated. A large difference in indicators between atmospheric pressure zones generates a strong and rapid movement of air masses above the earth's surface.

Features of wind measurement

In order to correctly correlate the data of meteorological services with your real position or to make a measurement correctly, you need to know what standard conditions professionals use.

• The measurement of the strength and speed of the wind takes place at a height of ten meters on an open flat surface.
• The name of the wind direction is given by the cardinal direction from which it blows.

Managers of water transport, as well as lovers of spending time in nature, often purchase anemometers that determine the speed, which is easy to correlate with the wind force in points. There are waterproof models. For convenience, devices of various compactness are produced.

In the Beaufort system, the description of the height of the waves, correlated with a certain force of wind in points, is given for the open sea. It will be much less in shallow water areas and coastal zones.

From personal to global use

Sir Francis Beaufort not only had a high military rank in the navy, but was also a successful practical scientist who held important posts, a hydrographer and cartographer, who brought great benefits to the country and the world. One of the seas in the Arctic Ocean, washing Canada and Alaska, bears his name. An Antarctic island is named after Beaufort.

A convenient system for estimating wind strength in points, available for fairly accurate determination of the severity of the phenomenon "by eye", Francis Beaufort created for his own use in 1805. The scale had a gradation from 0 to 12 points.

In 1838, the system of visual assessment of weather and wind strength in points began to be officially used by the British Navy. In 1874 it was adopted by the international synoptic community.

In the 20th century, several more improvements were made to the Beaufort scale - the ratio of points and a verbal description of the manifestation of the elements with wind speed (1926), and five more divisions were added - gradation points for the strength of hurricanes (USA, 1955).

Criteria for estimating wind strength in Beaufort points

In its modern form, the Beaufort scale has several characteristics that allow, in combination, to most accurately correlate a specific atmospheric phenomenon with its indicators in points.

• First, it is verbal information. Verbal description of the weather.
• Average speed in meters per second, kilometers per hour and knots.
• The impact of moving air masses on characteristic objects on land and sea is determined by typical manifestations.

Non-dangerous wind

Safe wind is determined in the range from 0 to 4 points.

A wind of 5 points, characterized as "fresh", or fresh breeze, can be called borderline. Its speed ranges from 8 to 10.7 meters per second (29-38 km/h, or 17 to 21 knots). Thin trees sway along with the trunks. Waves rise up to 2.5 (average up to two) meters. Sometimes there are splashes.

Wind that brings trouble

With a wind force of 6 points, strong phenomena begin that can cause damage to health and property.

Dangerous force of the wind

Wind force from ten to twelve points is dangerous and is characterized as a strong (storm) and severe storm (violent storm), as well as a hurricane (hurricane).

Wind uproots trees, damages buildings, destroys vegetation, destroys buildings. The waves make a deafening noise from 9 meters and above, long. At sea, they reach a dangerous height even for large ships - from nine meters and above. Foam covers the water surface, visibility is zero or close to such an indicator.

The speed of movement of air masses is from 24.5 meters per second (89 km / h) and reaches from 118 kilometers per hour with a wind force of 12 points. Violent storms and hurricanes (winds of magnitudes 11 and 12) are very rare.

Additional five points to the classical Beaufort scale

Since hurricanes are also not identical to each other in terms of intensity and degree of damage, in 1955 the United States Weather Bureau adopted an addition to the standard Beaufort classification in the form of five scale units. Wind strength from 13 to 17 points inclusive - these are clarifying characteristics for destructive hurricane winds and their accompanying environmental phenomena.

How to protect yourself when the elements are raging?

If the storm warning of the Ministry of Emergency Situations catches in an open area, it is better to follow the advice and reduce the risk of accidents.

First of all, you should pay attention to warnings every time - there is no guarantee that the atmospheric front will come to the area where you are, but you also cannot be sure that it will bypass it again. All items should be removed or securely fastened, to protect pets.

If a heavy wind catches in a fragile structure - a garden house or other light structures - it is better to close the windows from the air movement side, and if necessary, strengthen them with shutters or boards. On the leeward, on the contrary, slightly open and fix in this position. This will eliminate the danger of an explosive effect from the pressure difference.

It is important to remember that any strong wind can bring unwanted precipitation - in winter it is snowstorms and snowstorms, in summer dust and sand storms are possible. It should also be borne in mind that strong winds can occur even in absolutely clear weather.

Wind- this is a horizontal movement (air flow parallel to the earth's surface), resulting from uneven distribution of heat and atmospheric pressure and directed from a high pressure zone to a low pressure zone

The wind is characterized by speed (strength) and direction. Direction is determined by the sides of the horizon from which it blows, and is measured in degrees. Wind speed measured in meters per second and kilometers per hour. The strength of the wind is measured in points.

Wind in boots, m/s, km/h

Beaufort scale- conditional scale for visual assessment and recording of wind strength (speed) in points. Initially, it was developed by the English admiral Francis Beaufort in 1806 to determine the strength of the wind by the nature of its manifestation at sea. Since 1874, this classification has been accepted for widespread (on land and sea) use in international synoptic practice. In subsequent years, it was changed and refined (Table 2). The state of complete calm at sea was taken as zero points. Initially, the system was thirteen-point (0-12 bft, on the Beaufort scale). In 1946 the scale was increased to seventeen (0-17). The strength of the wind in the scale is determined by the interaction of the wind with various objects. In recent years, the strength of the wind is more often estimated by the speed, measured in meters per second - at the earth's surface, at a height of about 10 m above an open, flat surface.

The table shows the Beaufort scale, adopted in 1963 by the World Meteorological Organization. The sea wave scale is nine-point (the parameters are given for a large sea area; in small water areas, the wave is less). Descriptions of the action from the movement of air masses are given "for the conditions of the earth's atmosphere near the earth's or water surface", with an air density of about 1.2 kg / m3 and positive temperature. On the planet Mars, for example, the ratios will be different.

Wind strength in points on the Beaufort scale and sea waves

To make it easier to remember(compiled by: site author site)

3 - Weak - 5 m / s (~ 20 km / h) - leaves and thin branches of trees continuously sway
5 - Fresh - 10 m / s (~ 35 km / h) - pulls out big flags, whistles in the ears
7 - Strong - 15 m / s (~ 55 km / h) - telegraph wires are buzzing, it is difficult to go against the wind
9 - Storm - 25 m / s (90 km / h) - wind knocks down trees, destroys buildings

* The length of the wind wave on the surface of water bodies (rivers, seas, etc.) is the smallest distance, horizontally, between the tops of adjacent ridges.

Dictionary:

Breeze– a weak coastal wind with a strength of up to 4 points.

normal wind- acceptable, optimal for something. For example, for sports windsurfing, you need sufficient wind thrust (at least 6-7 meters per second), and when parachuting, on the contrary, calm weather is better (excluding lateral drift, strong gusts near the earth's surface and dragging the dome after landing).

storm is called a long and stormy, up to a hurricane, wind with a force of more than 9 points (gradation on the Beaufort scale), accompanied by destruction on land and strong waves at sea (storm). Storms are: 1) squall; 2) dusty (sandy); 3) dust free; 4) snow. Squall storms start suddenly and end just as quickly. Their actions are characterized by enormous destructive power (such a wind destroys buildings and uproots trees). These storms are possible everywhere in the European part of Russia, both at sea and on land. In Russia, the northern border of the distribution of dust storms passes through Saratov, Samara, Ufa, Orenburg and the Altai mountains. Snow storms of great strength occur on the plains of the European part and in the steppe part of Siberia. Typically, storms are caused by the passage of an active atmospheric front, a deep cyclone, or a tornado.

Squall- a strong and sharp gust of wind (Peak gusts) with a speed of 12 m / s and above, usually accompanied by a thunderstorm. At a speed of more than 18-20 meters per second, a heavy wind blows away poorly fixed structures, signs and can break billboards and tree branches, cause power lines to break, which creates a danger to people and cars under them. A gusty, squally wind occurs during the passage of an atmospheric front and with a rapid change in pressure in a baric system.

Vortex- atmospheric formation with rotational movement of air around a vertical or inclined axis.

Hurricane(typhoon) - a wind of destructive force and considerable duration, the speed of which exceeds 120 km/h. "Lives", i.e. moves, a hurricane usually lasts 9-12 days. Forecasters give it a name. The hurricane destroys buildings, uproots trees, demolishes light structures, breaks wires, and damages bridges and roads. Its destructive force can be compared to an earthquake. Homeland hurricanes - ocean expanses, closer to the equator. Cyclones saturated with water vapor from here leave to the west, more and more twisting and increasing speed. The diameters of these giant whirlwinds are several hundred kilometers. Hurricanes are most active in August and September.
In Russia, hurricanes most often occur in the Primorsky and Khabarovsk Territories, Sakhalin, Kamchatka, Chukotka, and the Kuril Islands.

Tornadoes are vertical vortices; squalls are more often horizontal, included in the structure of cyclones.

The word "tornado" is Russian, and comes from the semantic concept of "twilight", that is, a gloomy, thunderous situation. The tornado is a giant rotating funnel, inside which there is low pressure, and any objects that are in the way of the tornado are sucked into this funnel. As he approaches, a deafening roar is heard. A tornado moves above the ground at an average speed of 50–60 km/h. Deaths are short-lived. Some of them "live" seconds or minutes, and only a few - up to half an hour.

On the North American continent, a tornado is called tornado, and in Europe thrombus. A tornado can lift a car into the air, uproot trees, cripple a bridge, destroy the upper floors of buildings.

The Guinness Book of Records, as the most terrible and destructive in the history of observations, included a tornado in Bangladesh, observed in 1989. Despite the fact that the inhabitants of the city of Shaturia were warned in advance about the approach of a tornado, 1300 people became its victims.

In Russia, tornadoes are more frequent in the summer months, in the Urals, the Black Sea coast, in the Volga region and Siberia.

Forecasters classify hurricanes, storms and tornadoes as emergency events with a moderate propagation speed, so most often it is possible to announce a storm warning in time. It can be transmitted through civil defense channels: after the sound of sirens " Attention everyone!"must listen to the message of the local television and radio.

Symbols on meteorological maps of weather phenomena associated with wind

In meteorology and hydrometeorology, the direction of the wind ("where it blows from") is indicated on the map in the form of an arrow, the type of plumage of which shows the average speed of the air flow. In air navigation - the name of the direction is different to the opposite. In navigation on the water, the unit of speed (knot) of a vessel is taken to be one nautical mile per hour (ten knots correspond to approximately five meters per second).

On the weather map, a long feather of the wind arrow means 5 m/s, a short one - 2.5 m/s, in the form of a triangular flag - 25 m/s (follows after a combination of four long lines and 1 short one). In the example shown in the figure, there is a wind with a force of 7-8 m/s. With an unstable wind direction, a cross is placed at the end of the arrow.

The picture shows the symbols for the direction and speed of the wind used on weather maps, as well as an example of drawing icons and fragments from a hundred-cell matrix of weather symbols (for example, a snowstorm and a blowing snow, when there is a rise and redistribution of previously fallen snow in the surface air layer).

These symbols can be seen on the synoptic map of the Hydrometeorological Center of Russia (http://meteoinfo.ru) compiled as a result of the analysis of current data on the territory of Europe and Asia, which schematically shows the boundaries of the zones of warm and cold atmospheric fronts and the direction of their movements along the earth's surface.

What to do if there is a storm warning?

1. Close and secure all doors and windows tightly. Glue strips of plaster crosswise on the glass (so that fragments do not fly apart).

2. Prepare a supply of water and food, medicines, a flashlight, candles, a kerosene lamp, a battery receiver, documents and money.

3. Turn off gas and electricity.

4. Remove items from balconies (yards) that could be blown away by the wind.

5. From light buildings, move to more durable or civil defense shelters.

6. In a village house, move to the most spacious and durable part of it, and best of all - to the basement.

8. If you have a car, try to drive as far as possible from the epicenter of the hurricane.

Children from kindergartens and schools must be sent home in advance. If the storm warning comes too late, the children should be placed in basements or the center of buildings.

It is best to wait out a hurricane, a tornado or a storm in a shelter, a pre-prepared shelter, or at least in a basement. However, often, a storm warning is given just a few minutes before the arrival of the elements, and during this time it is not always possible to get to the shelter.

If you were outside during a hurricane

2. You can not be on bridges, overpasses, overpasses, in places where flammable and toxic substances are stored.

3. Hide under the bridge, reinforced concrete canopy, in the basement, cellar. You can lie down in a hole or any depression. Protect eyes, mouth and nose from sand and earth.

4. You can not climb onto the roof and hide in the attic.

5. If you are driving in a flat area, stop but do not leave the vehicle. Close its doors and windows more tightly. Cover the radiator side of the engine during a snow storm. If the wind is not strong, you can shovel the snow from the car from time to time so as not to be buried under a thick layer of snow.

6. If you are in public transport, leave it immediately and seek shelter.

7. If the elements caught you on an elevated or open place, run (crawl) towards any shelter (to rocks, forest) that could extinguish the force of the wind, but beware of falling branches and trees.

8. When the wind has died down, do not immediately leave the shelter, as a squall may repeat in a few minutes.

9. Stay calm and don't panic, help the injured.

How to behave after natural disasters

1. Leaving the shelter, look around for overhanging objects and parts of structures, broken wires.

2. Do not light gas and fire, do not turn on electricity until special services check the state of communications.

3. Do not use the elevator.

4. Do not enter damaged buildings, do not approach broken electrical wires.

5. The adult population provides assistance to rescuers.

Devices

The exact wind speed is determined using an instrument - an anemometer. If there is no such device, you can make a home-made wind-measuring "Wild board" (Fig. 1), with sufficient measurement accuracy for wind speeds up to ten meters per second.

Rice. 1. Homemade Wind Measuring Board-Wild Vane:
1 - vertical tube (600 mm long) with a welded pointed upper end, 2 - front horizontal weather vane rod with a counterweight ball-weight; 3 – weather vane impeller; 4 - upper frame; 5 - horizontal axis of the board hinge; 6 - wind board (weighing 200 g). 7 - lower fixed vertical rod with indicators of the cardinal points fixed on it, in eight points: N - north, south - south, 3 - west, B - east, NW - northwest, NE - northeast, SE - southeast, SW - southwest; No. 1 - No. 8 - wind speed indicator pins.

The weather vane is installed at a height of 6 - 12 meters, above an open flat surface. Under the weather vane, arrows indicating the direction of the wind are fixedly fixed. Above the weather vane to the tube 1 on the horizontal axis 5 is hinged to the frame 4 wind board 6 measuring 300x150 mm. The weight of the board is 200 grams (adjusted according to the reference device). Extending back from frame 4 is an arc segment attached to it (with a radius of 160 mm) with eight pins, of which four are long (140 mm each) and four are short (100 mm each). The angles at which they are fixed are with the vertical for the pin No. 1-0 °; №2 - 4°; No. 3 - 15.5°; #4 - 31°; No. 5 - 45.5 °; #6 - 58°; #7 - 72°; No. 8-80.5°.
The wind speed is determined by measuring the angle of deflection of the board. Having determined the position of the wind board between the arc pins, refer to Table. 1, where this position corresponds to a certain wind speed.
The position of the board between the pins gives only an approximate indication of the wind speed, especially since the wind strength changes quickly and often. The board never remains long in any one position, but constantly fluctuates within certain limits. Observing the changing inclination of this board for 1 minute, its average inclination is determined (calculation by averaging the maximum values) and only after that the average minute wind speed is judged. For a high wind speed exceeding 12-15 m/s, the readings of this device have low accuracy (in this limitation - the main drawback of the considered scheme) ...

Application

Average wind speed on the Beaufort scale in different years of its application

table 2

The Hurricane Scale was developed by Herbert Saffir and Robert Simpson in the early 1920s to measure the potential damage from a hurricane. It is based on numerical maximum wind speeds and includes an estimate of storm waves in each of the five categories. In Asian countries, this natural phenomenon is called a typhoon (translated from Chinese as “great wind”), and in North and South America it is called a hurricane. When quantifying wind flow speed, the following abbreviations apply: km/h / mph– kilometers / miles per hour, m/s- meters per second.

table 3

tornado scale

The tornado scale (Fujita-Pearson scale) was developed by Theodore Fujita to classify tornadoes according to the degree of damage caused by wind. Tornadoes are typical mainly for North America.

table 4

Glossary of terms:

Leeward side of the object (protected from the wind by the object itself; an area of ​​increased pressure, due to strong flow deceleration) faces where the wind blows. In the picture, on the right. For example, on the water, small ships approach larger ships from their leeward side (there they are protected by the hull of a large ship from waves and wind). "Smoking" plants-enterprises should be located, in relation to residential urban buildings - on the leeward side (in the direction of the prevailing winds) and separated from these areas by fairly wide sanitary protection zones.


windward side object (hill, sea vessel) - on the side from which the wind blows. On the windward side of the ridges, ascending movements of air masses occur, and on the leeward side, a downward airfall occurs. Most of the precipitation (in the form of rain and snow), due to the barrier effect of mountains, falls on their windward side, and on the leeward side, a collapse of colder and drier air begins.

In meteorology, when indicating the direction of the wind, the division of the circle into sixteen parts is used, according to 16-beam rhumb rose(after 22.5 degrees). For example, north-northeast is designated as NNE (the first letter is the main direction, to which the rhumb is closer). Four main directions: North, East, South, West.

Approximate calculation of dynamic wind pressure per square meter of a billboard (perpendicular to the plane of the structure) installed near the road of the carriageway. In the example, the maximum storm wind speed expected at a given location is assumed to be 25 meters per second.

Calculations are carried out according to the formula:
P = 1/2 * (air density) * V^2 = 1/2 * 1.2 kg/m3 * 25^2 m/s = 375 N/m2 ~ 38 kilograms per square meter (kgf)

Note that the pressure increases with the square of the speed. Take into account and include in the construction project sufficient margin of safety, stability (depending on the height of the support post, and on the critical angles of inclination of each particular column), resistance to strong gusts of wind and precipitation, in the form of snow and rain.

At what wind strength cancel flights of civil aviation aircraft

The reason for the violation of the flight schedule, delays or cancellation of flights can be a storm warning from weather forecasters, at the airports of departure and destination.

The meteorological minimum required for a safe (regular) takeoff and landing of an aircraft is the allowable limits for changes in a set of parameters: wind speed and direction, line of sight, the state of the airfield runway, and the height of the cloud base. Bad weather, in the form of intense precipitation (rain, fog, snow and blizzard), with extensive frontal thunderstorms, can also cause cancellation of flights from the air harbor.

The values ​​of meteorological minima may differ for specific aircraft (by their types and models) and airports (by class and availability of sufficient ground equipment, depending on the features of the terrain surrounding the airfield and existing high mountains), as well as due to the qualifications and flight experience of the crew pilots , commander of the ship. The worst minimum is taken into account and for execution.

Departure ban - possible in case of bad weather at the destination airport, if there are not, nearby, two alternative air harbors with acceptable weather conditions.

In strong winds, aircraft take off and land against the air flow (by taxiing, for this, to the appropriate lane). In this case, not only safety is ensured, but also the takeoff run and landing run are significantly reduced. Limitations on the lateral and tailwind components of the wind speed, for most modern civil aircraft, are approximately: 17-18 and 5 m/s, respectively. The danger of a large roll, demolition and reversal of an airliner, during its takeoff and landing, is represented by an unexpected and strong gusty wind (squall).

https://www.meteorf.ru - Roshydromet (Federal Service for Hydrometeorology and Environmental Monitoring). Hydrometeorological Research Center of the Russian Federation.

Www.meteoinfo.ru is a new website of the Hydrometeorological Center of the Russian Federation.

193.7.160.230/web/losev/osad.gif - Watch a video animation with a predictive synoptic weather map - precipitation, dynamics of cyclones and anticyclones for the coming days, showing horizontal movements of isobars (atmospheric pressure isolines) of the calculated weather model.

Www.ada.ru/Guns/ballistic/wind/index.htm - For hunters about the effect of wind on bullet flight, ballistic calculator.

Directory ru.wikipedia.org/wiki/Climate_Moscow - metropolitan weather stations and statistical data on the average monthly values ​​of the main weather parameters (temperature, wind speed, cloudiness, precipitation in the form of rain and snow), days when absolute temperature records were recorded, as well as the coldest and warmest years in Moscow and the region.

Https://meteocenter.net/weather/ - Russian weather from the Meteocenter.

Https:// www.ecomos.ru/kadr22/ postyMeteoMoskwaOblast.asp - Meteorological network (stations and posts) on the territory of the Moscow region. and in neighboring regions (Vladimir, Ivanovo, Kaluga, Kostroma, Ryazan, Smolensk, Tver, Tula and Yaroslavl regions)

Https:// www.ecomos.ru/kadr22/ sostojanieZagrOSnedelia.asp - environmental reports on the state of environmental pollution in Moscow (VDNH, Balchug and Tushino weather stations) and the region for the past week.

Meteorological hazards are natural processes and phenomena that occur in the atmosphere under the influence of various natural factors or their combinations, which have or may have a damaging effect on people, farm animals and plants, economic facilities and the natural environment.

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

The wind is characterized by:
1. Wind direction - determined by the azimuth 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 = 1609 km; 1 nautical mile = 1853 km).
3. Wind force - measured by the pressure that it exerts on 1 m2 of surface. The strength of the wind varies almost proportional to the speed,
therefore, the strength of the wind is often estimated not by pressure, but by speed, which simplifies the perception and understanding of these quantities.

Many words are used to indicate the movement of the wind: tornado, storm, hurricane, storm, typhoon, cyclone and many local names. To systematize them, all over the world use Beaufort scale, which allows you to very accurately estimate the strength of the wind in points (from 0 to 12) according to its effect on ground objects or on waves in the sea. This scale is also convenient in that it allows, according to the signs described in it, to fairly accurately determine the wind speed without instruments.

Beaufort scale (Table 1)

Breeze (light to strong breeze) sailors refer to the wind as having a speed of 4 to 31 miles per hour. In terms of kilometers (factor 1.6) it will be 6.4-50 km/h

Wind speed and direction determine weather and climate.

Strong winds, significant changes in atmospheric pressure and a large amount of precipitation cause dangerous atmospheric vortices (cyclones, storms, squalls, hurricanes) that can cause destruction and loss of life.

Cyclone is the general name for eddies with reduced pressure in the center.

An anticyclone is an area of ​​high pressure in the atmosphere with a maximum in the center. In the Northern Hemisphere, the winds in the anticyclone blow counterclockwise, and in the Southern Hemisphere - clockwise, in the cyclone the wind movement is reversed.

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

Hurricanes are classified into three types based on wind speed:
- Hurricane (32 m/s and more),
- strong hurricane (39.2 m/s or more)
- fierce hurricane (48.6 m/s and more).

Cause of these hurricane winds is the occurrence, as a rule, on the line of collision 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) in a spiral towards the middle and up, in the northern hemisphere, counterclockwise.

Such cyclones, depending on the place of their occurrence and structure, are usually divided into:
- tropical cyclones found over warm tropical oceans, usually moves westward during formation, and curves poleward after formation.
A tropical cyclone that reaches unusual strength is called hurricane if he is born in the Atlantic Ocean and adjacent seas; typhoon - in the Pacific Ocean or its seas; cyclone - in the Indian Ocean region.
mid-latitude cyclones can form both over land and over water. They usually move from west to east. A characteristic feature of such cyclones is their great "dryness". The amount of precipitation during their passage is much less than in the zone of tropical cyclones.
The European continent is affected by both tropical hurricanes that originate in the central Atlantic and cyclones of temperate latitudes.
Storm – a type of hurricane, but has a lower wind speed 15-31
m/sec.

The duration of storms is from several hours to several days, the width is from tens to several hundreds of kilometers.
Storms are divided into:

2. Stream storms – These are local phenomena of small distribution. They are weaker than whirlwinds. They are subdivided:
- stock - the air flow moves down the slope from top to bottom.
- Jet - characterized by the fact that the air flow moves horizontally or up the slope.
Stream storms pass most often between chains of mountains connecting valleys.
Depending on the color of the particles involved in the movement, black, red, yellow-red and white storms are distinguished.
Depending on the wind speed, storms are classified:
- storm 20 m/s and more
- strong storm 26 m/s and more
- severe storm of 30.5 m/s and more.

Squall – a sharp short-term increase in wind up to 20–30 m/s and higher, accompanied by a change in its direction associated with convective processes. Despite the short duration of squalls, they can lead to catastrophic consequences. Squalls in most cases are associated with cumulonimbus (thunderstorm) clouds, either local convection or a cold front. A squall is usually associated with heavy rainfall and thunderstorms, sometimes with hail. Atmospheric pressure during a squall rises sharply due to the rapid precipitation, and then falls again.

If possible, limit the area of ​​impact, all of the listed natural disasters are classified as non-localized.

Dangerous consequences of hurricanes and storms.

Hurricanes are one of the most powerful forces of the elements and, in terms of their detrimental effects, are not inferior to such terrible natural disasters as earthquakes. This is due to the fact that hurricanes carry enormous energy. Its amount released by a hurricane of average power during 1 hour is equal to the energy of a nuclear explosion of 36 Mt. In one day, the amount of energy that would be enough to provide electricity to a country like the United States is released. And in two weeks (the average duration of the existence of a hurricane), such a hurricane releases energy equal to the energy of the Bratsk hydroelectric power station, which it can generate in 26 thousand years. The pressure in the hurricane zone is also very high. It reaches several hundred kilograms per square meter of a fixed surface located perpendicular to the direction of wind movement.

The hurricane destroys strong and demolishes light buildings, devastates sown fields, breaks wires and knocks down power lines and communication poles, damages highways and bridges, breaks and uproots trees, damages and sinks ships, causes accidents in utility networks, in production. There are cases when hurricane winds destroyed dams and dams, which led to large floods, threw trains off the rails, tore bridges off their supports, knocked down factory pipes, and threw ships onto land. Hurricanes are often accompanied by heavy downpours, which are more dangerous than the hurricane itself, as they cause mudflows and landslides.

Hurricanes vary in size. Usually, the width of the zone of catastrophic destruction is taken as the width of the hurricane. Often, the area of ​​storm force winds with relatively little damage is added to this zone. Then the width of the hurricane is measured in hundreds of kilometers, sometimes reaching 1000 km. For typhoons, the destruction zone is usually 15-45 km. The average duration of a hurricane is 9-12 days. Hurricanes occur at any time of the year, but most often from July to October. In the remaining 8 months they are rare, their paths are short.

The damage caused by a hurricane is determined by a whole complex of various factors, including the terrain, the degree of development and the strength of buildings, the nature of vegetation, the presence of population and animals in its zone of action, the time of year, preventive measures taken and a number of other circumstances, the main of which is velocity head of the air flow q, proportional to the product of the atmospheric air density and the square of the air flow velocity q = 0.5 pv 2.

According to building codes and regulations, the maximum normative value of wind pressure is q = 0.85 kPa, which, at an air density of r = 1.22 kg/m3, corresponds to wind speed.

For comparison, we can cite the calculated values ​​of the velocity head used to design nuclear power plants for the Caribbean region: for buildings of category I - 3.44 kPa, II and III - 1.75 kPa and for open installations - 1.15 kPa.

Every year, about a hundred powerful hurricanes march across the globe, causing destruction and often claiming human lives (Table 2). On June 23, 1997, a hurricane swept over most of the Brest and Minsk regions, as a result of which 4 people died and 50 were injured. In the Brest region, 229 settlements were de-energized, 1071 substations were put out of action, roofs were torn off from 10-80% of residential buildings in more than 100 settlements, up to 60% of agricultural production buildings were destroyed. In the Minsk region, 1,410 settlements were de-energized, hundreds of houses were damaged. Broken and uprooted trees in forests and forest parks. At the end of December 1999, Belarus also suffered from a hurricane wind that swept across Europe. Power lines were cut, many settlements were de-energized. In total, 70 districts and more than 1,500 settlements were affected by the hurricane. Only in the Grodno region, 325 transformer substations failed, in the Mogilev region even more - 665.

table 2
Impact of some hurricanes

Tornado (tornado)- whirlwind movement of air, propagating in the form of a giant black column with a diameter of up to hundreds of meters, inside which there is a rarefaction of air, where various objects are drawn.

Tornadoes occur both over the water surface and over land, much more often than hurricanes. Very often they are accompanied by thunderstorms, hail and showers. The speed of air rotation in the dust column reaches 50-300 m/s and more. During its existence, it can travel up to 600 km - along a strip of terrain several hundred meters wide, and sometimes up to several kilometers, where destruction occurs. The air in the column rises in a spiral and draws in dust, water, objects, people.
Dangerous factors: buildings caught in a tornado due to a vacuum in the air column are destroyed from the pressure of air from the inside. It uproots trees, overturns cars, trains, lifts houses into the air, etc.

Tornadoes in Belarus occurred in 1859, 1927 and 1956.

Accepted for use in international synoptic practice. Initially, it did not indicate wind speed (added in 1926). In 1955, to distinguish between hurricane winds of varying strengths, the US Weather Bureau expanded the scale to 17.

It should be noted that the wave height in the scale is given for the open ocean, and not the coastal zone.

see also

Links

• Description of the Beaufort scale with photographs of the state of the sea surface.

Wikimedia Foundation. 2010 .

• Baikal (spaceship)
• non-metals

See what the "Beaufort Scale" is in other dictionaries:

BEAUFORT SCALE- (Beaufort scale) at the beginning of the 19th century. the English admiral Beaufort proposed to determine the strength of the wind by the windage that at the time of observation the given ship itself or other sailing ships in its visibility can carry, and evaluate this strength by scale points, ... ... Marine Dictionary

Beaufort scale- a conditional scale for visual assessment of the strength (speed) of the wind, based on its impact on ground objects or on the water surface. It is mainly used for ship observations. Has 12 points: 0 calm (0 0.2 m / s), 4 moderate ... ... Emergencies Dictionary

Beaufort scale- The scale for determining the strength of the wind, based on a visual assessment of the state of the sea, is expressed in points from 0 to 12 ... Geography Dictionary

Beaufort scale- 3.33 Beaufort scale: A twelve-point scale adopted by the World Meteorological Organization for the approximate estimation of wind speed from its effect on ground objects or from waves on the high seas. Source … Dictionary-reference book of terms of normative and technical documentation

Beaufort scale- a scale for determining the strength of the wind by visual assessment, based on the effect of the wind on the state of the sea or on land objects (trees, buildings, etc.). It is mainly used for observations from ships. Adopted in 1963 by the World ... ... Geographic Encyclopedia

A conditional scale in points in the form of a table for expressing the speed (strength) of the wind by its action on ground objects, by waves at sea and the ability of the wind to set sailing ships in motion. The scale was proposed in 1805-1806. British Admiral F. ... ... Wind Dictionary

BEAUFORT SCALE- wind force estimation system. It was proposed by the English hydrographer F. Beaufort in 1806. It is based on the visual perception of the action of the wind on the water surface, smoke, flags, ship superstructures, on the shore, structures. The assessment is made in points ... ... Marine encyclopedic reference book

Beaufort scale- a conditional scale in points from 0 to 12 for visual assessment of the force (speed) of the wind in points by sea waves or by the action of ground objects: 0 shtnl (calmness 0 0.2 m / s); 4 moderate wind (5.5 7.9 m/s); 6 strong wind (10.8 13.8 m/s); 9… … Dictionary of military terms

BEAUFORT SCALE- In damage management: conditional scale for visual assessment and recording of wind strength (speed) in points or waves at sea. It was developed and proposed by the English admiral Francis Beaufort in 1806. Since 1874, it has been adopted for use in ... ... Insurance and risk management. Terminological dictionary

Beaufort scale- The Beaufort scale is a twelve-point scale adopted by the World Meteorological Organization for an approximate assessment of wind speed by its effect on ground objects or by waves on the high seas. The average wind speed is indicated on ... ... Wikipedia

Accepted for use in international synoptic practice. Initially, it did not indicate wind speed (added in 1926). In 1955, to distinguish between hurricane winds of varying strengths, the US Weather Bureau expanded the scale to 17.

It should be noted that the wave height in the scale is given for the open ocean, and not the coastal zone.

see also

Links

• Description of the Beaufort scale with photographs of the state of the sea surface.

Wikimedia Foundation. 2010 .

See what the "Beaufort Scale" is in other dictionaries:

- (Beaufort scale) at the beginning of the 19th century. the English admiral Beaufort proposed to determine the strength of the wind by the windage that at the time of observation the given ship itself or other sailing ships in its visibility can carry, and evaluate this strength by scale points, ... ... Marine Dictionary

Conditional scale for visual assessment of the strength (speed) of the wind, based on its impact on ground objects or on the water surface. It is mainly used for ship observations. Has 12 points: 0 calm (0 0.2 m / s), 4 moderate ... ... Emergencies Dictionary

Beaufort scale- The scale for determining the strength of the wind, based on a visual assessment of the state of the sea, is expressed in points from 0 to 12 ... Geography Dictionary

Beaufort scale- 3.33 Beaufort scale: A twelve-point scale adopted by the World Meteorological Organization for the approximate estimation of wind speed from its effect on ground objects or from waves on the high seas. Source … Dictionary-reference book of terms of normative and technical documentation

A scale for determining the strength of the wind by visual assessment, based on the effect of the wind on the state of the sea or on land objects (trees, buildings, etc.). It is mainly used for observations from ships. Adopted in 1963 by the World ... ... Geographic Encyclopedia

BEAUFORT SCALE- a conditional scale in points in the form of a table for expressing the speed (strength) of the wind by its action on ground objects, by sea waves and the ability of the wind to set sailing ships in motion. The scale was proposed in 1805-1806. British Admiral F. ... ... Wind Dictionary

BEAUFORT SCALE- wind force estimation system. It was proposed by the English hydrographer F. Beaufort in 1806. It is based on the visual perception of the action of the wind on the water surface, smoke, flags, ship superstructures, on the shore, structures. The assessment is made in points ... ... Marine encyclopedic reference book

Beaufort scale- a conditional scale in points from 0 to 12 for visual assessment of the force (speed) of the wind in points by sea waves or by the action of ground objects: 0 shtnl (calmness 0 0.2 m / s); 4 moderate wind (5.5 7.9 m/s); 6 strong wind (10.8 13.8 m/s); 9… … Dictionary of military terms

BEAUFORT SCALE- In damage management: conditional scale for visual assessment and recording of wind strength (speed) in points or waves at sea. It was developed and proposed by the English admiral Francis Beaufort in 1806. Since 1874, it has been adopted for use in ... ... Insurance and risk management. Terminological dictionary

The Beaufort scale is a twelve-point scale adopted by the World Meteorological Organization for an approximate estimate of wind speed by its effect on ground objects or by waves on the high seas. The average wind speed is indicated on ... ... Wikipedia