TORNADOES HURRICANE STORMS
From the point of view of the possibility of carrying out preventive measures, dangerous natural processes, as a source emergency situations, can be predicted with a very short lead time (from several days to several hours). Strong winds with speeds over 20 m/sec and heavy rainfall can be observed in almost all regions of the Republic of Belarus. According to forecasts, the number of emergencies caused by strong winds, rain and hail will generally remain at the same level, or will increase due to the manifestation of poorly predicted local meteorological processes against the background of significant deterioration of facilities utilities and social sphere.
The territory of any region is subject to the complex effects of dozens of dangerous natural phenomena, development and negative manifestation which in the form of catastrophes and natural disasters annually causes enormous material damage and leads to human casualties. The most characteristic natural phenomena In terms of frequency depending on the time of year, hurricanes, storms and tornadoes lead to emergencies.
Blizzards are accompanied by the transfer of huge masses of snow from one place to another. At the same time, large areas are filled up.
Storm- a type of hurricane and storm. Hurricanes and storms differ in wind speed, which during a hurricane reaches 32 m/s or more, and during a storm 15 - 20 m/s. The losses from a hurricane are greater than from a storm.
Tornado- an ascending vortex of extremely rapidly rotating air in the form of a huge funnel destructive force, which contains moisture, sand and other suspended matter. Rising vortices of rapidly rotating air, having the appearance of a dark column with a diameter of several tens to hundreds of meters with a vertical, sometimes curved axis of rotation. The tornado seems to “hang” from the cloud to the ground in the form of a giant funnel, inside which the pressure is always low, so the “suction” effect appears. It lifts animals, people, cars, small houses into the air and carries them hundreds of meters, tears off roofs, and uproots trees. average speed winds from 15 - 18 m/s, up to 50 m/s, front width 350 - 400 m. Path length - from hundreds of meters to tens and hundreds of kilometers. Sometimes tornadoes are accompanied by precipitation in the form of hail and heavy rain.
The most common natural disasters in Europe are hurricanes and floods. In terms of economic losses and the volume of subsequent insurance payments, hurricanes and floods are the most financially significant. Hurricanes Lota and Martin in December 1999 caused damage estimated at €5 billion, damaging crops, forests and infrastructure settlements.
Hurricane- This is an extremely fast and strong movement of air, often of great destructive power and considerable duration.
During hurricanes, the width of the zone of catastrophic destruction reaches several hundred kilometers (sometimes thousands of kilometers). A hurricane lasts 9 - 12 days (a storm - from several hours to several days, the width of the front during a storm is several hundred kilometers), causing a large number of casualties and destruction. Transverse size tropical cyclone(also called a tropical hurricane, typhoon) is much smaller - only a few hundred kilometers, its height is up to 12-15 km. The pressure in hurricanes drops much lower than in extratropical cyclone. At the same time, the wind speed reaches 400-600 km/h. In the core of a tornado, the pressure drops very low, so tornadoes “suck” into themselves various, sometimes very heavy objects, which are then transported over long distances. People caught in the center of the tornado die.
As surface pressure continues to fall, the tropical disturbance becomes a hurricane when wind speeds begin to exceed 64 knots. A noticeable rotation develops around the center of the hurricane, because as spiraling bands of precipitation swirl around the eye of a hurricane. The heaviest precipitation and strongest winds are associated with the eye wall.
Eye - area 20-50 km in diameter, located in the center of a hurricane, where skies are often clear, winds are light, and pressure is lowest.
Wall of the eye - a ring of cumulonimbus clouds swirling around the eye. The heaviest precipitation and the strongest winds are found here.
Spiral stripes precipitation -
bands of powerful convective showers directed towards the center of the cyclone.
Tornado(tornado) - a vortex horizontal movement of air that occurs in a thundercloud and descends to the surface of the earth in the form of an overturned funnel, the diameter of which is up to hundreds of meters. The air inside the column rotates counterclockwise, rising upward in a spiral at a speed of several tens of m/s. Because The radius near the ground decreases, then the speed at the surface of the earth reaches supersonic values. The pillar moves at a speed of up to 20 m/s and covers a distance of 40-60 km. Inside the tornado, the air pressure is so great that buildings crumble due to the pressure of the air in them. The ability of tornadoes to plunge oblong objects (straws, sticks, debris, etc.) into trees, walls of houses, the ground, etc. is amazing. Small stones pierce glass and thin metal.
Hurricanes that occur in tropical latitudes have speeds of up to 64 knots (74 mph) and are capable of causing damaging winds, heavy rainfall and flooding that can result in massive damage to residential infrastructure, private property and loss of life. Hurricane in terms of impact on environment not inferior earthquakes: buildings, power and communication line masts, transport highways are destroyed, trees are broken and uprooted, sea vessels are capsized and automobile transport. Often storms and hurricanes are accompanied by rain and snowfall, which further complicates the situation. As a result of strong winds, a wind surge of water occurs at the mouths of rivers, settlements and arable lands are flooded, and enterprises are forced to stop their production.
Moscow, night from 20 to 21 June “As reported news agencies with reference to representatives of medical and emergency services and the press center of the mayor's office, wind gusts in some places reached 31 meters per second. During a heavy downpour, 35 mm of precipitation fell - the capital's monthly norm. According to preliminary data, at least 45 thousand trees were broken and uprooted, and 744 street lighting networks were broken. More than a hundred city routes public transport was inactive due to 585 breaks in trolleybus and tram contact networks. Heavy winds damaged high-voltage power lines - 75 damage was recorded on lines with voltages of 500, 220 and 110 kilovolts. Construction and road equipment accidents occurred in some places in the capital. Many cars and buildings were damaged, including the Kremlin and the Bolshoi Theater. About one and a half thousand houses were left without roofs. A crane collapsed in a river port and sank 2 ships. The storm wind, the speed of which, according to weather forecasters, reached 90 kilometers per hour in the hurricane zone, also caused casualties: 7people died, 122 were hospitalized and 161 people sought medical help.”Weather forecasters may not receive timely warnings about the hurricane. Absence storm warning leads to colossal material damage, loss of life, and sometimes significant humanitarian crises. Effective resolution of crisis situations requires coordination and concentration of resources to ensure timely and appropriate assistance is provided to countries and people in need. In 1992, to coordinate humanitarian operations outside the European Union, the EU Office for humanitarian aid(ECHO).
Improvement of the weather forecast service (introduction of a hurricane warning system for space-based surveillance equipment) allows urgent evacuation population from threatening areas and reduce the number of human casualties. Research is also being carried out on the effect on hurricanes (especially those that are just emerging) by introducing certain chemical reagents (silver iodide) into the clouds, in some cases causing premature precipitation and weakening the destructive power of the hurricane
To reduce the impact of natural disasters, actions and measures are being taken at both the national and regional levels, although a single targeted policy has not yet been developed. Action plans for emergency situations, including guidelines for responding to various natural disasters, have been developed in all countries European Union, but they are largely untested in practice and are unlikely to lead to satisfactory results when implemented (EEA 1999).
TACTICAL CHARACTERISTICS
The destructive effects of hurricanes are associated primarily with wind, but the subsequent phase of rainfall and flooding is much more dangerous. These phenomena acquire a formidable character and turn into rampant disasters with catastrophic consequences on the scale of entire states or even several countries in any geographical area.
Related components of hurricanes:
Floods.
Temporary flooding of low-lying areas river valleys, are caused by heavy rains, cyclones, hurricanes and other meteorological reasons. The significant harm that floods cause to humanity is to some extent explained by the problem of forecasting at the present time. Heavy rainfall and offshore waters carried ashore by strong winds can cause water levels to rise by more than 50 cm (20 in) in just 24 hours. The drainage systems in many cities are unable to handle this rise due to the soft topography common to many coastal areas where hurricanes occur.
Storm surge of water.
There may often be an increase in the water level in the water area, sometimes over several meters. This is the most destructive characteristic, devastating the lower levels of coastal structures. Greatest danger occurs when water levels rise during high tide.
Violation of living conditions of the population
Utilities. Administrative and industrial buildings, residential buildings and economic facilities are damaged. Gas and water supply systems, sewerage systems, boiler houses, heating mains, transformer substations, power line feeders, electrical panels. Hurricane winds tear off the roofs of houses and office buildings, knock down trees and lighting poles. Underpasses, street intersections, water lines and drains are flooded.
Transport. Blockages form on the roads from fallen trees, Traffic on highways is interrupted. Are blurred sections of asphalt, railway and dirt roads, the movement of passenger trains is delayed. Air terminals and bridges are damaged and bridge crossings.
Agriculture. Squally winds, accompanied by heavy rain and hail, damage the roofs of residential buildings and granaries. Causes flooding of houses, buildings, private households, bridge crossings, agricultural land.Agricultural crops, orchards and vegetable gardens are dying over large areas. Farms and sheds are damaged, die hundreds of heads of livestock and poultry. As a result of the disaster, the water level in the rivers rises and exceeds critical levels. Subject to prolonged flooding arable land, thousands of hectares of perennial grasses, pastures and meadows.
There is a danger of intensification of coastal destruction and landslide processes.
Interrupted telephone communications and power supply disruptions in settlements with a population of tens and hundreds of thousands of people.
Almost the entire population may be temporarily resettled from the affected areas.
Particular caution for ministries and departments involved in eliminating the consequences of emergencies and disasters natural character, cause dangerous objects: hydroelectric power stations, nuclear power plants, chemical, biological, fire and explosion hazards, industrial, military warehouses and storage facilities. Social facilities: airports, train stations, transnational railways and highways, Insurance companies, banks, strategic economic facilities and, most importantly, energy potential, on which the performance of the entire complex of urban infrastructure depends.
Meteorological dangerous phenomena– natural processes and phenomena that arise in the atmosphere under the influence of various natural factors or combinations thereof, providing or capable of providing damaging effect on people, farm animals and plants, economic objects and the natural environment.
Wind - this is the movement of air in parallel earth's surface resulting from uneven distribution heat and atmospheric pressure and directed out of the zone high pressure in a low pressure zone.
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 it exerts on 1 m2 of surface. The strength of the wind varies almost proportionally to the speed,
therefore, wind force is often measured not by pressure, but by speed, which simplifies the perception and understanding of these quantities.
Many words are used to denote the movement of wind: tornado, storm, hurricane, gale, typhoon, cyclone and many local names. To systematize them, people 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) by its effect on ground objects or on waves at sea. This scale is also convenient because it allows you to quite accurately determine the wind speed without instruments based on the characteristics described in it.
Beaufort scale (Table 1)
Points |
Verbal definition |
Wind speed, |
Wind action on land |
|
On the land |
On the sea |
|||
0,0 – 0,2 |
Calm. Smoke rises vertically |
Mirror smooth sea |
||
Quiet breeze |
0,3 –1,5 |
The direction of the wind is noticeable by the direction of the smoke, |
Ripples, no foam on the ridges |
|
Light breeze |
1,6 – 3,3 |
The movement of the wind is felt by the face, the leaves rustle, the weather vane moves |
Short waves, crests do not capsize and appear glassy |
|
Light breeze |
3,4 – 5,4 |
Leaves and thin branches of trees sway, the wind flutters the upper flags |
Short, well-defined waves. The ridges, overturning, form foam, and occasionally small white lambs are formed. |
|
Moderate breeze |
5,5 –7,9 |
The wind raises dust and pieces of paper and moves thin tree branches. |
The waves are elongated, white caps are visible in many places. |
|
Fresh breeze |
8,0 –10,7 |
Thin tree trunks sway, waves with crests appear on the water |
The waves are well developed in length, but not very large; whitecaps are visible everywhere. |
|
Strong breeze |
10,8 – 13,8 |
Thick tree branches sway, wires hum |
Large waves begin to form. White foamy ridges occupy large areas. |
|
strong wind |
13,9 – 17,1 |
The tree trunks are swaying, it’s difficult to walk against the wind |
The waves pile up, the crests break off, the foam lies in stripes in the wind |
|
Very strong wind storm) |
17,2 – 20,7 |
The wind breaks tree branches, it is very difficult to walk against the wind |
Moderately high, long waves. Spray begins to fly up along the edges of the ridges. Stripes of foam lie in rows downwind. |
|
Storm |
20,8 –24,4 |
Minor damage; the wind tears off smoke hoods and tiles |
High waves. The foam falls in wide dense stripes in the wind. The crests of the waves capsize and crumble into spray. |
|
Heavy storm |
24,5 –28,4 |
Significant destruction of buildings, trees are uprooted. Rarely happens on land |
Very high waves with long bends |
|
Fierce Storm |
28,5 – 32,6 |
Large destruction over a large area. Very rarely observed on land |
Exceptionally high waves. Vessels are hidden from view at times. The sea is all covered with long flakes of foam. The edges of the waves are blown into foam everywhere. Visibility is poor. |
|
32.7 or more |
Heavy objects are carried by wind over considerable distances |
The air is filled with foam and spray. The sea is all covered with stripes of foam. Very poor visibility. |
||
Breeze (light to strong breeze) sailors call winds that have a speed of 4 to 31 mph. In terms of kilometers (coefficient 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 large amounts of precipitation cause dangerous atmospheric vortices(cyclones, storms, squalls, hurricanes) that can cause destruction and loss of life.
Cyclone – common name vortices with reduced pressure in the center.
An anticyclone is an area high blood pressure in an atmosphere with a maximum in the center. In the Northern Hemisphere, the winds in an anticyclone blow counterclockwise, and in the Southern Hemisphere they blow clockwise; in a cyclone the wind movement is reversed.
Hurricane
- wind of destructive force and significant 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/sec, reaching 40-60 m/sec, and sometimes up to 100 m/sec.
Hurricanes are classified into three types based on wind speed:
- Hurricane
(32 m/s or more),
- strong hurricane
(39.2 m/s or more)
- violent hurricane
(48.6 m/s or more).
The reason for such hurricane winds is the emergence, as a rule, on the line of collision of 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 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 origin and structure, are usually divided into:
-
tropical cyclones meet over warm tropical oceans, in the stage of formation usually moves to the west, and after the end of formation they bend towards the poles.
A tropical cyclone that has reached unusual strength is called hurricane,
if it is born in the Atlantic Ocean and its adjacent seas; typhoon -
in the Pacific Ocean or its seas; cyclone –
in the region Indian Ocean.
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 its passage is significantly less than in the zone tropical cyclones.
The European continent is affected by both tropical hurricanes originating in the central Atlantic and cyclones of temperate latitudes.
Storm
–
a type of hurricane, but has a lower wind speed of 15-31
m/sec.
The duration of storms is from several hours to several days, the width is from tens to several hundred kilometers.
Storms are divided:
2. Stream storms
–
These are local phenomena of small distribution. They are weaker than vortex storms. They are divided:
- 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 a slope.
Stream storms most often occur 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/sec or more
- strong storm 26 m/sec or more
- severe storm of 30.5 m/sec or 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 are most often associated with cumulonimbus (thunderstorm) clouds of either local convection or a cold front. A squall is usually associated with showers and thunderstorms, sometimes with hail. Atmospheric pressure during a squall rises sharply due to rapid precipitation, and then falls again.
If it is possible to limit the impact zone, 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 nature and in their harmful effects are not inferior to such terrible ones. natural disasters like earthquakes. This is explained by the fact that hurricanes carry enormous energy. The amount of it released by an average-power hurricane for 1 hour is equal to the energy of a nuclear explosion of 36 Mt. In one day, an amount of energy is released that would be enough to supply a country like the United States with electricity for six months. And in two weeks (the average duration of a hurricane’s existence), such a hurricane releases energy equal to the energy of the Bratsk hydroelectric power station, which it can produce in 26 thousand years. The pressure in the hurricane zone is also very high. It reaches several hundred kilograms per square meter a fixed surface located perpendicular to the direction of wind movement.
Hurricane wind destroys strong and demolishes light buildings, devastates sown fields, breaks wires and knocks down power and communication line poles, damages highways and bridges, breaks and uproots trees, damages and sinks ships, causes accidents in utility and energy networks, in production. There are known cases when hurricane winds destroyed dams and dams, which led to large floods, threw trains off the rails, tore bridges from their supports, knocked down factory chimneys, and washed ships ashore. Hurricanes are often accompanied by heavy downpours, which are more dangerous than the hurricane itself, as they cause mudflows and landslides.
Hurricane sizes vary. Usually, the width of the catastrophic destruction zone is taken as the width of a hurricane. Often this zone is supplemented with an area of storm force winds with relatively little damage. Then the width of the hurricane is measured in hundreds of kilometers, sometimes reaching 1000 km. For typhoons, the destruction strip is usually 15-45 km. The average duration of a hurricane is 9-12 days. Hurricanes occur at any time of the year, but are most common 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 various factors, including the terrain, the degree of development and strength of buildings, the nature of vegetation, the presence of population and animals in the area of its action, the time of year, preventive measures taken and a number of other circumstances, the main one of which is the speed pressure of the air flow q, proportional to the product of density atmospheric air per square of air flow speed q = 0.5pv 2.
According to building codes and regulations, the maximum standard value of wind pressure is q = 0.85 kPa, which, with an air density of r = 1.22 kg/m3, corresponds to wind speed.
For comparison, we can give the calculated values of the velocity pressure used to design nuclear power plants for the region Caribbean: 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 taking away human lives(Table 2). June 23, 1997 over for the most part A hurricane swept through the Brest and Minsk regions, as a result of which 4 people were killed and 50 were injured. In the Brest region, 229 settlements were de-energized, 1,071 substations were disabled, roofs were torn off from 10-80% of residential buildings in more than 100 settlements, and up to 60% of agricultural buildings were destroyed. In the Minsk region, 1,410 settlements were cut off and hundreds of houses were damaged. Trees in forests and forest parks were broken and uprooted. At the end of December 1999, Belarus also suffered from hurricane winds that swept across Europe. Power lines were broken, and many settlements were without power. In total, 70 districts and more than 1,500 settlements were affected by the hurricane. In the Grodno region alone, 325 transformer substations were out of order, in the Mogilev region even more - 665.
table 2
Effects of some hurricanes
Location of the disaster, year |
Death toll |
Number of wounded |
Associated phenomena |
Haiti, 1963 |
Not recorded |
||
Not recorded |
|||
Honduras, 1974 |
Not recorded |
||
Australia, 1974 |
|||
Sri Lanka, 1978 |
Not recorded |
||
Dominican Republic, 1979 |
|||
Not recorded |
|||
Indochina, 1981 |
Not recorded |
Flood |
|
Bangladesh, 1985 |
Not recorded |
Flood |
Tornado (tornado)- vortex movement of air, spreading 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, into which they are drawn various items.
Tornadoes occur both over the water surface and over land, much more often than hurricanes. Very often they are accompanied by thunderstorms, hail and downpours. The speed of air rotation in the dust column reaches 50-300 m/sec or 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, and people.
Hazardous factors: buildings caught in a tornado due to vacuum in the air column are destroyed by air pressure from the inside. It uproots trees, overturns cars, trains, lifts houses into the air, etc.
Tornadoes occurred in the Republic of Belarus in 1859, 1927 and 1956.
Tornadoes and hurricanes.
Famous film director E.A. Ryazanov beautifully said in verse:
"There is no bad weather
Every weather is a blessing.
Rain and snow, any time of year
We must accept it gratefully."
We completely agree with these kind full of love to native nature in the words of Eldar Alexandrovich. However, it should be noted that sometimes the weather deteriorates to such an extent that it becomes little like grace. Unfortunately, this happens often. We are talking about weather phenomena such as tornadoes and hurricanes.
A tornado is an atmospheric vortex with a vertical, sometimes curved axis of rotation. It arises due to instability of the atmosphere at the interface between warm and cold air. A tornado is usually born from a rain cloud. This cloud is called the mother cloud and is usually located at an altitude of up to 10 kilometers, i.e. at the interfaces that separate air masses with different wind speeds, with different temperatures and air humidity. From the cloud, cold air descends to the surface of the earth, meeting the warm air rising upward. A rotational movement of air occurs - a tornado. Inside the tornado, the pressure drops significantly - to a value below 700 mbar (normal Atmosphere pressure equals 1013 mbar). A tornado, having descended to the surface of the earth, spins noisily and, like a giant vacuum cleaner, sucks in dust, sand, water, grass, stones and other objects.
Tornadoes move at the speed with which the wind drives them: 30-60 km/h. The average distance a tornado travels is about 25 kilometers, and the average width of a tornado (a kind of average diameter) is 150 meters.
A tornado is rated from 0 to 5 depending on its intensity and the consequences (destruction) caused. The intensity of a tornado is determined by the speed of the internal wind, which can range from 18 to 140 meters per second. Therefore, the nature of the destruction caused by a tornado can be very different - from weak to catastrophic.
In America and Western Europe The terms "tornado" and "thrombus" are used. These words are synonyms for the word "tornado", because... denote the same phenomenon - a rotating vortex (tornado in Spanish "rotating", tromb in French "pipe" - the shape of a vortex along the vertical). By the way, the direction of air rotation in a tornado funnel in the northern hemisphere is counterclockwise, and in the southern hemisphere it is clockwise, which is the result of the action of the so-called. Coriolis force, depending on the rotation of the Earth. You can observe the action of this force every day when you release water from the bathtub: the resulting whirlpool spins counterclockwise (we are addressing the residents in this case northern hemisphere our planet).
If we talk about the territory of Russia, then tornadoes are a rather rare occurrence here. On average, they occur twice a year, usually in the summer (June-July) and most often in the afternoon, i.e. during hours of maximum transfer of heat and air masses in the atmosphere.
Here are some examples of tornadoes that happened in Russia. The most destructive were the tornadoes that swept through Moscow on June 29, 1904 and through Ivanovo on June 9, 1984. The “mileage” of the first tornado was only 30 kilometers, and the second - 160. The tornado of 1904 in the Moscow Sokolniki Park knocked down almost all the trees, and tore some of them up by their roots. In Ivanovo, the tornado passed in a strip of 500 meters in a direction to the north, tore off the roofs of houses, felled trees, poles and power line supports, and overturned carriages, not to mention cars.
The largest in diameter - up to 1 kilometer - was a tornado that passed through Bashkir Nature Reserve in July 1935.
If for Russia tornadoes are a rarity, then in the USA tornadoes (as tornadoes are usually called here) are a real national disaster: after all, on average in the country they happen no less often twice a day(!) Apparently, this is the “retribution” of the United States for their geographical position between the ice of Alaska and Canada and the warm Gulf of Mexico.
Now briefly about hurricanes. A hurricane is a wind with a speed of more than 33 meters per second (i.e. 120 km/h or more), blowing for a long time (several hours or even days).
According to the international Beaufort scale, wind speed is assessed by points: a total of 17 points, including zero. Calm is scored zero - the wind speed is 0.0 - 0.2 m/s; visible action of the wind - the smoke rises vertically, the leaves on the trees are motionless.
A force 11 wind has a speed of 28.5 - 32.6 m/s and is characterized as a severe storm that causes great destruction.
A force 12 wind has a speed of 32.7 - 36.9 m/s and is characterized as a hurricane causing devastating destruction.
Hurricanes with wind speeds of 37 m/s or more are assessed at points 13-17.
In meteorology, the concept of squall wind or squall is also used. This is the name for winds that quickly (within 10-15 minutes) reach hurricane speeds (33 m/s) and just as quickly lose this speed to 1-2 m/s.
The consequences of heavy winds on land can be destruction of light buildings, overturned cars, fallen trees, and at sea, heavy winds threaten even large ships with a real disaster.
There is also a scale of hurricane categories, the so-called Saffir-Simpson scale. This scale divides all hurricanes into five categories based on atmospheric pressure at the eye (i.e. the center), wind speed, and damage caused.
A hurricane of the first (lowest) category includes a hurricane with a wind speed of 34-42 m/s and a pressure in the eye over 980 mbar; the damage caused is insignificant. A hurricane of the fifth (highest) category is characterized by atmospheric pressure in the eye below 920 mbar and wind speed above 68 m/s (above 245 km/h); the damage caused is colossal.
Typhoons are a dangerous natural phenomenon.
Separately, we need to talk about such phenomena as typhoons. These are also atmospheric vortices, but they are generated by tropical cyclones. Cyclone is an area low blood pressure in an atmosphere with a minimum in the center. The main area where tropical cyclones occur is the water area of all oceans adjacent to the equator and located between the parallels of 10-20 degrees northern and southern latitudes. A tropical cyclone forms where the surface of the water has a high temperature (27°C or higher), exceeding the temperature of the adjacent air by 2-3°C or more.
Warm and moist air rises, and its huge masses, due to the rotation of the Earth, begin a circular motion with a simultaneous shift to an area of lower atmospheric pressure. With a significant pressure difference between the middle and the periphery of the cyclone, the wind speed around the middle increases rapidly. If it reaches hurricane force - 33 m/s or more, and in in some cases- up to 100 m/s, this means that the cyclone has turned into a typhoon. This is a simplified diagram of the formation of a typhoon.
Typhoons are different huge size: their diameter (width) reaches 300-700 kilometers, and in some cases - up to 1000 km, height - from 5 to 15 km. Warm and moist air rising upward forms rain clouds over the typhoon area, carrying huge amounts of water. The torrential rains brought by the typhoon continue for hours and often lead to floods.
Originating in the northwestern part tropical zone Pacific typhoons demonstrate their destructive power on southern shores China and Korea, in the north of Vietnam, on the eastern shores of Japan and Kuril Islands. They do not leave the Primorsky Territory of Russia alone, as well as Sakhalin and Kamchatka.
The name "typhoon" in Chinese means " strong wind" and is used to designate tropical cyclones raging in the areas just listed. Cyclones of similar strength raging in the eastern part of the Pacific Ocean and in the Atlantic are called hurricanes, and the same phenomena off the coast of Hindustan are called storms or simply cyclones.
Cyclones also occur in temperate latitudes, although much less frequently than in the tropics. Of course, not every cyclone gains hurricane force and turns into a typhoon. Every year on globe There are an average of 20-25 typhoons.
Cyclones are giant disturbances of atmospheric air associated with sharp fluctuations in pressure and temperature of air masses. These fluctuations, and therefore weather fluctuations in vast areas of the Earth, depend mainly on the interaction of the ocean and the atmosphere, on the nature of the exchange of energy and moisture between them. The mechanism of cyclone formation is not entirely clear. It is very difficult to determine with a sufficient degree of certainty where and when a cyclone will occur, because Among other factors, it is necessary to take into account not only the general nature of atmospheric circulation, but also the characteristics of air currents in each specific area. Research on cyclones is complicated, in particular, by the fact that it is usually not possible to deliver scientific equipment to the site of the event in a timely manner: cyclones last only a few days (at least in the initial stage). In addition, on Earth, especially in the oceans, there are many hard-to-reach areas where it is generally impossible to deliver scientific equipment.
In recent years, cyclone research has become more effective through the use of special aerosondes equipped with the necessary measuring instruments and launched on command from the Earth from spacecraft that monitor the corresponding areas of the World Ocean.
In December 1944, 300 miles east of the island. Luzon (Philippines) ships of the US Third Fleet found themselves in the hurricane zone. As a result of its impact, over 800 people were killed, 3 destroyers sank, 2 other ships were damaged, and 146 aircraft on aircraft carriers were washed overboard or damaged.
Hurricanes, storms and tornadoes are wind meteorological phenomena.
Wind is the movement of air relative to the earth's surface, resulting from an uneven distribution of atmospheric pressure and directed from high pressure to low.
It is characterized by direction and speed (force). The direction is determined by the azimuth of the side of the horizon from which the wind is blowing, and is measured in meters per second (m/s), kilometers per hour (km/h), in knots, or approximately in points on the Beaufort scale.
The Beaufort scale is used to express wind strength in points visual assessment. It was adopted by the World Meteorological Organization in 1963.
The main cause of hurricanes, storms and tornadoes is the cyclical activity of the atmosphere.
A cyclone is a moving atmospheric vortex with a diameter of one hundred to several thousand kilometers, which is characterized by a system of hurricane winds blowing counterclockwise in the northern hemisphere of the Earth and clockwise- in the south.
Depending on their origin, cyclones are divided into tropical and extratropical.
The immediate cause of tropical cyclones is the condensation of steam in a vast layer of moist air over the ocean, releasing huge amount energy, extratropical - significant contrasts in temperature and pressure of adjacent air masses.
All cyclones have the same structure. The central part of cyclones, which has the lowest pressure, light clouds and weak winds, is usually called the "eye of the storm" ("eye of the hurricane"). The outer part, in which maximum pressure and hurricane speeds of rotation of air masses are usually observed, is the cyclone wall. This wall abruptly gives way to the peripheral part, where atmospheric pressure decreases and the winds gradually weaken.
The speed of movement of cyclones is very different. Its average value for tropical cyclones is 50-60 km/h, and the maximum is 150-200 km/h. The speed of extratropical cyclones averages 30-40 km/h, and sometimes reaches 100 km/h. Cyclones Atlantic Ocean are commonly called hurricanes, and western Pacific tropical cyclones are typhoons.
Hurricane (typhoon)- wind of enormous destructive force, having a speed above 30 m/s, or 12 degrees on the Beaufort scale.
Depending on where cyclones originate, hurricanes are also divided into tropical and extratropical.
The most important characteristic of a hurricane is wind speed. Long-term meteorological observations show that wind speeds during hurricanes reached 30-50 m/s in most regions of the European part of the Russian Federation, and 60-90 m/s or more in the Far East.
Important characteristics of hurricanes are also their width and duration, speed of movement and paths of movement.
The width of the catastrophic destruction zone is usually taken as the width of a hurricane. This tropical hurricane zone ranges in width from 20 to 200 km or more. Extratropical hurricanes are characterized by a significantly greater width of their action, which can be several thousand kilometers.
The duration of a hurricane on average reaches 9-12 days or more.
The paths of tropical hurricanes are predominantly meridional, while those of extratropical hurricanes are mainly from west to east.
Hurricanes occur at any time of the year, but the vast majority of them pass through the territory of the Russian Federation in August and September. The timing of their passage has a certain cyclicity, which contributes to their more accurate forecasting. For the convenience of monitoring the movement of hurricanes and in order to reduce errors in the transmission of information, weather forecasters assign them short, easy-to-remember female or male names or use four-digit numbering.
Hurricanes are also accompanied by such phenomena as heavy rains, snowfalls, hail, and electrical discharges. Hurricane winds often lead to dust and snow storms.
Tempest (storm)- very strong continuous wind with a speed of over 20 m/s, causing great destruction on land and disturbances at sea. Storms are characterized by lower wind speeds than hurricanes, and their duration of action is up to several days.
Depending on the time of year, their formation and the involvement of particles of different compositions in the air, dusty, dustless, snow and squall storms are distinguished.
Dust (sand) storms are accompanied by the transfer of large amounts of soil and sand. They occur in desert, semi-desert and plowed steppes and are capable of transporting millions of tons of dust over hundreds and even thousands of kilometers. Such storms occur mainly in the summer, during dry winds, sometimes in the spring and during snowless winters. In the steppe zone they usually arise due to irrational plowing of land. In the Russian Federation northern border The distribution of dust storms passes through Saratov, Samara, Ufa, Orenburg and the foothills of Altai.
Dustless storms are characterized by the absence of dust entrainment into the air and a relatively smaller scale of destruction and damage. However, as they move further, they can turn into dust or snow storms, depending on the composition and condition of the surface layer of the earth and the presence of snow cover.
Snow storms are also characterized by significant wind speeds, which contribute to the movement of huge masses of snow through the air in winter. Their duration ranges from several hours to several days. They have a relatively narrow range (from several kilometers to several tens of kilometers). Snow storms of great force occur on the plains of the European part of the Russian Federation and in the steppe part of Siberia.
Squalls are characterized by an almost sudden onset, an equally rapid end, a short duration of action and enormous destructive power. These storms are widespread throughout the European part of Russia, both in marine areas (here they are called squalls) and on land.
Tornado (tornado)- an atmospheric vortex that arises in a thundercloud and often spreads to the surface of the earth. It has the appearance of a column, sometimes with a curved axis of rotation, with a diameter of tens to hundreds of meters with funnel-shaped extensions at the top and bottom. The air in a tornado rotates counterclockwise at a speed of up to 100 m/s and at the same time rises in a spiral, drawing dust, water and various objects from the ground. Tornadoes do not exist for long - from several minutes to several hours, during which time they travel from hundreds of meters to several tens of kilometers.
Tornadoes are divided according to their structure into dense (sharply limited) and vague (unclearly limited). Based on time and spatial impact, they are divided into small short-acting tornadoes (up to 1 km), small tornadoes (up to 10 km) and tornadoes - hurricane vortices (more than 10 km).
A tornado is almost always clearly visible, and a deafening roar is heard as it approaches. The average speed of its movement is 50-60 km/h.
Tornadoes are observed in all regions of the globe. In Russia, tornadoes most often occur in the Volga region and Siberia, in the Urals and the Black Sea coast.
Consequences of hurricanes, storms and tornadoes. Hurricanes, storms and tornadoes are among the most powerful forces of nature and in their destructive effects are often comparable to an earthquake. They cause significant destruction, cause great damage to the national economy, and lead to casualties.
The main indicator that determines the destructive effect of hurricanes, storms and tornadoes is the high-speed pressure of air masses, which determines the force of the dynamic impact and has a throwing effect.
Hurricane winds damage strong and demolish light buildings, break power and communication lines, devastate fields, break and uproot trees.
People caught in the hurricane zone are defeated by being thrown through the air (thrown), struck by flying objects, struck and crushed by collapsed structures.
Buildings collapsing under the influence of hurricanes crush those inside them. As a result, people die, receive injuries of varying severity and concussion.
Possible destruction of buildings and structures during hurricanes and tornadoes is divided into complete, strong and weak.
In case of complete destruction, only the foundations and basements of buildings, as well as buried structures and shelters are preserved. Such objects cannot subsequently be restored or used. Such destruction is rarely observed.
Severe damage is characterized by the collapse of the walls of the upper floors. The lower floors and underground rooms of the buildings are preserved. Utility networks are torn or deformed.
The possibility of restoring such objects is associated with their reconstruction.
With moderate damage, strong structures (walls, ceilings, stairs) are preserved. Damage to utility networks at joints is possible. Objects with such damage are restored in full.
Weak damage includes deformation of light extensions, window and door frames, cornices and roofs. Inside buildings, partitions and wall plaster are damaged. With such minor damage, restoration of the premises is carried out, as a rule, during the operation of the structures.
A hurricane, passing over the ocean, forms powerful clouds that are sources of catastrophic downpours that cause floods not only in coastal areas, but also over large areas of the continent. The rainfall that accompanies hurricanes is also the cause of natural phenomena such as mudflows and landslides.
A common secondary consequence of a hurricane is fires that occur as a result of accidents in power supply systems, leaks of flammable substances, and violations of the localization of fire sources at work and at home.
Storms, due to the fact that their characteristic wind speeds are much lower than those of hurricanes, lead to much less destructive consequences. However, if they are accompanied by the transfer of sand, dust or snow, significant damage is possible agriculture, transport and other industries.
Dust storms cover fields, populated areas and roads with a layer of dust and sand, sometimes reaching several tens of centimeters, over areas of hundreds of thousands of square kilometers. In such conditions, the harvest is significantly reduced or completely lost, and large amounts of effort and money are required to clean up settlements, roads and restore agricultural land.
Snow storms (blizzards) in our country often reach great strength over vast areas. Their consequence is the cessation of traffic in cities, rural areas and on roads, the death of farm animals and even people. Such situations disrupt the production rhythm throughout the country and require significant expenditure of effort and funds for restoration work, especially on railways and roads.
Strong winds at low air temperatures contribute to the occurrence of such dangerous meteorological phenomena, like ice, frost and ice. As a result, failure of overhead power and communication lines, contact networks of electrified transport, antenna masts and other similar structures is possible.
Thus, hurricanes and storms, dangerous in themselves, are characterized by destruction and casualties.
A tornado, in contact with the surface of the earth, often causes the same degree of destruction that occurs during strong hurricane winds, but over much smaller areas. These destructions are associated with the action of rapidly rotating air and a sharp upward rise of air masses. As a result, some objects (cars, light houses, roofs of buildings, people and animals) can be lifted off the ground and transported hundreds of meters, causing their destruction: people receive injuries and concussions, and sometimes die. At the same time, due to the entrainment of a huge number of objects into the air, significant indirect injuries to people are observed.
Tornado
Tornadoes, even if they are small, are the most powerful hurricanes in nature. Spinning and wriggling like snakes, they crawl out of the clouds and, descending to the ground, cause enormous devastation, destroying houses, throwing cars around like balls and uprooting trees. Those who survived an encounter with a tornado say that at the scene they found straws driven into tree trunks like nails. The sound of an approaching tornado is like the roar of a gigantic freight train.
The United States of America (USA) is the champion in the number of tornadoes. On average, there are up to 700 tornadoes per year in the United States (some states experience tornadoes more often than others). In 1953, there was one single tornado in Alaska, while in Kansas there were more than 1200. In second place after the United States is Australia with its measly 15 tornadoes per year.
How does a tornado or tornado form?
Added to a large thundercloud is wind blowing in the opposite direction. When this headwind reaches the cloud, it is directed sharply upward. If you look at the top of a thundercloud, you will see it swirl upward and then fall downward, while powerful currents of rising air bore the cloud upward. Sometimes this upward flow, encountering an oppositely directed flow of air in a cloud, begins to swirl.
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Why are tornadoes most common in the United States?
In the USA, tornadoes are called tornadoes. High above Rocky Mountains blow powerful westerly winds. Breaking out onto the plain, they encounter low, warm, humid winds with Gulf of Mexico. These air masses collide over the central states, forming strong hurricanes and tornado.
The nature of tornadoes and tornadoes
A rotating column of rising air is called a mesocyclone. This mass of swirling air and cloud, like the spout of a bathtub filled with water, is called a vortex. At the center of the vortex, atmospheric pressure drops, and more and more air is sucked into the throat of the vortex. No one knows exactly how much the pressure at the center of a tornado is reduced, but some scientists estimate it to be up to half of normal atmospheric pressure.
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