What is a tropical hurricane. Effects of tropical cyclones

The destructive activity of typhoons and hurricanes is carried out as a result of the combined action of the colossal force of the wind, the huge amount of precipitation, the stormy rise in the level of the ocean and the resulting giant waves.

The Beaufort scale for a unified assessment of the state of the sea from one (calm sea) to 12 points (hurricane - the sea is white from foam and waves reaching a height of 15 m) turned out to be unsuitable for characterizing wind speed during typhoons and hurricanes. To these 12 points, 5 more were added; the last 17 points corresponds to a wind speed of 460 km/h.

Modern instruments are not capable of registering wind speeds of more than 300 km/h. A record speed is considered to be approximately 400 km / h, which means not an instantaneous gust, but a wind blowing for 5 minutes. Separate gusts have a speed of 20 - 30% more.

In tropical cyclones, wind speeds often reach 300-400 km/h. Such speeds are not measurable. They are judged by the destruction that cyclones leave behind. These hurricanes often drop heavy rain and hail. Waterfalls falling from the sky and accompanied by the roar of the wind are terrifying. There are cases when, in areas of future typhoons, the surfaces of bays were covered with dead fish that died from excess fresh water.

Tropical cyclones on the way of movement cause huge material damage and claim many human lives.

The inhabitants of the Philippine Islands, Indochina and Japan have known the word "typhoon" since time immemorial. Typhoons in the Bay of Bengal have many victims. They contribute to the occurrence of storm floods that inundate low-lying, densely populated coasts.

There are cases when one typhoon claimed thousands of human lives, for example, typhoon Vera in September 1959 killed 5,500 people. This number will increase significantly if we take into account people who died later from starvation and disease.

The damage caused to material values ​​can be conditionally divided into direct and indirect. Direct is the damage that manifests itself directly during the storm (destruction of buildings, fires, loss of crops, etc.). Indirect damage is damage that manifests itself for a long time after the passage of typhoons and hurricanes over islands and continents. For example, the absence of a crop for several years in those fields from which the surface layer of soil was carried away, a reduction in production in destroyed factories and factories. The amount of indirect damage caused by a tropical cyclone can be several times greater than the amount of direct damage. Long-term statistics of observations of tropical cyclones made it possible to identify some patterns that relate the amount of damage caused to the physical characteristics of tropical cyclones. This allows you to get a rough idea of ​​the scale of the impending disaster.

biological significance cyclones lies in their ability to carry seeds of plants, and sometimes rather large animals, over great distances. Apparently, it was these winds that contributed to the settlement of many volcanic and coral islands that arose in the expanses of the oceans, and the migration of plants and animals. The hurricane of 1865 brought pelicans to Guadeloupe, previously unknown there.

The famous Great Hurricane in October 1780 destroyed the city of Savannah-la-Mar (Georgia, USA). According to an eyewitness, the inhabitants were petrified with amazement when they saw the approach of an unprecedented wave; sweeping away all obstacles with one gigantic squall, it flooded the city and demolished everything and everything. Seven days later, the storm reached its maximum intensity. She completely devastated the island of St. Lucia, where 6,000 people died under the ruins, and sank the English fleet anchored off the island. The sea here rose so high that it flooded the fleet and, bringing the ship on the crest of one of its giant waves, threw it onto the naval hospital, destroying the building with the weight of the ship. The hurricane then headed for the island of Martinique, where 40 French transport ships carrying 4,000 soldiers were sunk. The islands of Dominica, St. Eustatius, St. Vincent, Puerto Rico, located to the north, were also devastated and a large number of ships sunk in the path of the cyclone.

On the night of November 13, 1970, an incredible typhoon hit the coastal regions of East Pakistan (since 1971 People's Republic Bangladesh). A powerful wave up to 8 m high, raised by the wind, passed over a chain of densely populated islands. It was a colossal wall of water, seething and churning, a huge billow of water that the ocean threw up. Sweeping away everything in its path, it hit the coast and, together with a hurricane wind, brought catastrophic destruction. For several hours, these islands and part of the mainland coast were under water. The consequences of the typhoon are catastrophic: bridges were torn down, highways and railways were destroyed, entire villages were completely destroyed along with the inhabitants. More than 10 million people were affected by the typhoon, according to newspaper reports. The death toll exceeded half a million, and according to some sources, about a million people. One of the most powerful natural disasters in the history of mankind has happened.

An extraordinary hurricane hit 11 states in 1974 North America. Sowing death and destruction, the hurricane and its accompanying tornadoes in 8 hours left on their way, according to published data, 350 killed, thousands of wounded and missing. In the states of Illinois, Indiana, Ohio, Kentucky, West Virginia, Virginia, Tennessee, North Carolina, Alabama and Georgia, hundreds of houses and shops, schools, hospitals and churches were destroyed. Property damage, according to incomplete data, is estimated at $ 1 billion. Among the most severely affected by the hurricane is the city of Zinia in Ohio. According to eyewitnesses, the hurricane hit suddenly around 5 o'clock. evening, rumbled like a passenger train rushing at great speed. In a city of 25,000, more than 70% of buildings were completely or partially destroyed, including the state university. The city of Brandenberg ceased to exist. In Alabama, the cities of Jasper and Guin are razed to the ground.

On the eve of 1975, tropical cyclone "Tracy" almost completely destroyed the capital of the northern territory of Australia, Darwin - a city with a population of 44 thousand people. The wind force reached a speed of 260 km / h. The hurricane tore roofs off houses like balls, tossed tourist buses through the streets. Numerous cottages fell apart under the pressure of the wind, like houses of cards. But administrative buildings and high-rise hotels turned out to be hardly more stable. The business center of Darwin has been turned into mountains of rubble and debris. A large naval base located near the city was destroyed. Several ships sank.

In 1980, during August and September 1980 alone, there were four tropical cyclone developments in the northern hemisphere and one in the southern hemisphere, of which two were hurricanes in the Caribbean and three were typhoons in the Pacific.

Hurricane Alley was recorded in early August off the coast of Haiti and Jamaica. The wind speed in it reached 70 m/s. The second hurricane, Ermina, was observed in the 20th of September off the northern coast of Honduras, as well as off the coast of Mexico and Guatemala. The wind speed in it reached 30 m/s.

Typhoon Orchid originated in the Western Pacific Ocean and swept over the Japanese Islands on September 11-12 and South Korea causing significant damage and flooding. The influence of this typhoon became noticeable days later in the Khabarovsk and Primorsky Territories and on Sakhalin. Heavy rains and wind were observed, the wind speed in some places reached hurricane (33 m/s). About a month later, in mid-October, another typhoon came to the Japanese islands of Kyushu and Shikoku from the south, temporarily disrupting not only air, but also railway communication.

At the beginning of the third decade of September, Typhoon Kei appeared in the southeastern Pacific Ocean, in the center of which the wind speed reached 30-40 m/s.

There were tropical cyclones in subsequent years, both in the northern and southern hemispheres. In particular, tropical cyclones Eilena, which hit the Comoros in the Indian Ocean on January 10, 1983, and Andri, which caused great destruction on the northwestern coast of the island of Madagascar in the Indian Ocean, turned out to be very destructive.

The year 1985 was also a fruitful year for tropical cyclones: seven tropical cyclones - typhoons passed in the South China Sea during the summer and autumn of this year, causing catastrophic floods and human casualties in the coastal regions of Vietnam and China.

One of the typhoons, Lee, penetrated far north to the Korean Peninsula and, turning into an ordinary cyclone, brought with it heavy rains to the territory of the Soviet Primorye in mid-August.

Another typhoon on September 10-12 destroyed a third of the fruit crop and caused damage to about 90% of the cultivated area on the Japanese island of Honshu.

In late October, Typhoon Saling claimed the lives of more than 60 residents of the island of Luzon in the Philippines and caused more than 700 million pesos of damage to the island's farms. Almost simultaneously in the other hemisphere, in the Gulf of Mexico, another tropical cyclone arose - Hurricane Juan, which severely affected the inhabitants of several coastal states of the United States, and a month later - Hurricane Keith, which caused flooding and significant destruction in northern Cuba and the United States. Hurricane Keith in terms of intensity and extent of damage caused by about. Cuba and the coast of the Florida peninsula proved to be one of the most ferocious in the last 50 years; gusts of wind and ocean waves running ashore destroyed many thousands of houses, more than a million people had to be evacuated from disaster zones, and there were human casualties.

Tropical Cyclone Jeanne (September 2004) -- Caribbean Sea, Haiti. The death toll from heavy rains, floods and landslides on the island of Haiti caused by Hurricane Jeanne could reach 2,000, according to the Associated Press. As of September 23, almost 1,100 victims are already known, and another 1,250 people are missing. Most a large number of victims - in the city of Gonaives in the northern part of the island. According to authorities, 1,013 people died here. Representatives of the Red Cross fear the spread of epidemics through the water, in which the bodies of drowned people were located for several days. The water level in some places exceeds four meters, and as it declines, more and more victims are found. The President of Haiti called what is happening a humanitarian catastrophe and asked the international community for help. In May 2004, the island had already suffered one of the worst floods in history, which killed about 2.5 thousand people.

Hurricane Katrina is one of the most destructive hurricanes in US history. As a result of the disaster, 1,836 residents were killed and the economic damage amounted to $81.2 billion. Physical characteristics. Before it reached the coast of the United States, it was assigned a level 5 hurricane scale on the Saffir-Simpson Hurricane Scale. Fortunately, about 12 hours before landfall, the hurricane weakened to a Category 4 level. The wind speed during the hurricane reached up to 280 km / h (according to other reports, 62 m / s (? 223 km / h). August 27, 2005 passed over the coast of Florida near Miami and turned towards the Gulf of Mexico. August 29, 2005 reached south- east coast of the United States near Louisiana and Mississippi. Due to the location below sea level, many cities of the southeast coast of the United States were flooded. In New Orleans, this happened with 80% of the city, many buildings collapsed. Economic damage amounted to $ 125 billion. ( estimate, 2007).About 800,000 people were left without electricity and telephone service.The officially confirmed number of victims was 1407 people, according to later data 1600, of which more than 720 were in New Orleans; in addition, as of December 2005, 47 people were missing More than a quarter of the population of New Orleans (150 thousand people) still have not returned to the city (August 2006).

March 14, 2007 Madagascar again experienced the blow of the elements. Another tropical cyclone, Indlala, reached the northeast coast of the island, reaching category 3 in strength. The wind speed in this cyclone reached 115 knots with gusts up to 140 knots. Reportedly news agencies, over the past days, this cyclone claimed the lives of 36 people, 53 thousand 750 people were left homeless. Since December 2006, Indlala has become the fourth cyclone to hit Madagascar. On March 19, 2007, he left the island. While devastating floods are observed in the north of the island due to powerful cyclones, its southern part endures drought and famine. The cyclone season in the South Indian Ocean usually lasts from November to March. But the 2006/07 season differs from the previous ones in greater activity.

On October 7, 2008, Mexico was literally in the grip of tropical cyclones. Tropical Storm Marco has formed in the Gulf of Mexico. Wind gusts reached 27 m/s. Storm "Marco" came close to the coast. Brought torrential rains. On the other side of Mexico, over the Pacific Ocean, another cyclone is Hurricane Norbert.

Tropical cyclones, hurricanes, typhoons

especially dangerous phenomenon nature are deep cyclones of various origins, which are associated with strong winds, heavy precipitation, surges and high wind waves in the sea. The depth of a cyclone is determined by the air pressure at its center.

The size and power of deep cyclones depends on many factors and, first of all, on the place of their origin. The cyclones that originated in the tropical latitudes are distinguished by the greatest power. They are called tropical in contrast to extratropical cyclones, among which are cyclones of temperate latitudes and arctic cyclones. The higher the geographic latitude of the origin of the cyclone, the lower its maximum power.

Tropical cyclones carry colossal reserves of energy and have great destructive power. The kinetic energy of a medium-sized tropical cyclone is comparable to the explosion energy of several powerful hydrogen bombs and accounts for about 10% of the total kinetic energy northern hemisphere.

Most often (in 87% of cases) tropical cyclones occur between latitudes 5° and 20°. At higher latitudes, they occur only in 13% of cases. Tropical cyclones have never been recorded north of 35°N. sh. and south of 22° S. sh.

Tropical cyclones can occur at any time of the year in the tropical parts of all oceans except the southeast Pacific and the south Atlantic. Most often they are formed in the northern part of the tropical zone of the Pacific Ocean: here, on average, about 30 cyclones are traced per year. The main season for the development of tropical cyclones is August-September; in winter and spring, their frequency is very insignificant.

Tropical cyclones usually originate over the oceans, and then move over their water areas and come to the coast of continents, islands, bringing down on them the strongest winds, rain showers, causing a surge wave up to 8 m high, as well as waves in the open sea, over 10 m high.

Tropical cyclones that have reached significant intensity in each region have their own name. In the eastern part of the Pacific Ocean and in the Atlantic they are called hurricanes (from the Spanish word "uracan" or the English "hurricane"), in the countries of the Hindustan Peninsula - cyclones or storms, in the Far East - typhoons (from the Chinese word "tai", which means strong wind). There are also less common local names: “willy-willy” in Australia, “willy-wow” in Oceania and “baguio” in the Philippines.

To describe the intensity of tropical cyclones, the Saffir-Simpson scale is used (Table 1). 3.3.1.1. It shows that as the cyclone deepens, the wind speed and surge wave height increase in it, and the cyclone itself is classified either as a storm or as a hurricane from the first to the fifth categories.

This scale is used by almost all hurricane and typhoon watch centers. AT recent times The Saffir-Simpson scale has also been used to classify deep extratropical cyclones that have reached storm or hurricane strength. From this table it follows that hurricanes and typhoons have five categories (from a hurricane or typhoon of the first category H1 to a hurricane or typhoon of the fifth category H5). Tropical depressions and tropical storms are not categorized.

Table 3.3.1.1. Tropical cyclone scale

There are four stages in the life cycle of a tropical cyclone:

1. Stage of formation. It begins with the appearance of the first closed isobar. The pressure in the center of the cyclone drops to 990 mb. Only about 10% of tropical depressions develop further.

2. Stage young cyclone, or stage of development. The cyclone begins to deepen rapidly; there is a significant drop in pressure. Hurricane-force winds form a ring around the center with a radius of 40-50 km.

3. Stage of maturity. The pressure drop in the center of the cyclone and the increase in wind speed gradually stop. The area of ​​storm winds and intense showers is increasing in size. The diameter of tropical cyclones in the developmental stage and in the mature stage can vary from 60-70 to 1000 km.

4. Stage of attenuation. The beginning of the filling of the cyclone (growth of pressure in its center). Attenuation occurs when a tropical cyclone moves into an area of ​​more low temperatures surface of the water or when moving to land. This is due to a decrease in the influx of energy (heat and moisture) from the surface of the ocean, and when it comes to land, it is also due to an increase in friction against the underlying surface.

After leaving the tropics, a tropical cyclone may lose its specific properties and turn into an ordinary cyclone of extratropical latitudes. It also happens that tropical cyclones, remaining in the tropics, go to the mainland. Here they quickly fill up, but at the same time they manage to produce a lot of destruction.

Since ancient times, there has been a practice of assigning proper names to destructive hurricanes and typhoons. AT different times naming conventions have changed. For hundreds of years, Caribbean hurricanes have been named after saints. church calendar, on the day of which a destructive hurricane fell on a large settlement.

Under these names, hurricanes entered the annals and legends. An example is the hurricane Santa Anna, which hit Puerto Rico on July 26, 1825 with exceptional force. AT late XIX in. Australian meteorologist Clement Wragg began referring to tropical storms by female names. Since 1953, the National Hurricane Center of the United States began to publish preliminary lists, according to which Atlantic tropical storms were named.

Until 1979, only female names. Since 1979, both women's and male names. The practice of compiling preliminary lists of hurricanes and typhoons has spread to all regions. Now there are 11 such regions in the World Ocean. These preliminary lists for all regions are created and updated by a special international committee of the World Meteorological Organization (WMO).

The damaging factors of hurricanes and typhoons:

Kinetic wind energy;

Intense precipitation;

Surge wave;

Storm waves of considerable height.

Associated nuclear events: strong wind, heavy seas, heavy rains, heavy hail, high waters, floods, collapses, landslides, erosion and processing of coasts.

Hurricanes cause enormous damage to the coasts of the North and South America, islands in the way of their distribution. They hit these coasts with a frequency of once every few years, sometimes forming series within one year. One of the most destructive hurricanes - Mitch in October 1998 claimed the lives of 10,000 people in Honduras and Nicaragua and left 2 million people homeless.

The hurricane caused the most severe flooding in these countries in the last two hundred years. The total economic damage caused by the hurricane exceeded $5 billion. The world's greatest economic damage was caused by Hurricane Andrew, which swept over the United States from August 23 to 27, 1992. Insurers paid out $ 17 billion, which covered about 57% of the losses from the hurricane.

The underdeveloped countries of the Caribbean suffer the heaviest damage from hurricanes, the consequences of which they recover for years. Hurricanes in the middle latitudes are rare: once every 8-10 years. In January 1923, a hurricane captured the entire European part USSR, the center of the hurricane passed through Vologda. In September 1942, a hurricane swept over the central regions of the European part of our country.

The pressure difference was very great, and therefore in some places hurricane-speed winds were formed. The usual speed of cyclones is 30-40 km/h; but there are speeds of more than 80 km / h. The September 1942 cyclone traveled 2,400 km in one day (i.e., its speed was 100 km/h). On November 18, 2004, the hurricane hit Germany, then moved to Poland and Kaliningrad.

In Germany, the wind speed reached 160 km/h, in Poland - 130 km/h, in Kaliningrad - 120 km/h. 11 people died in these countries, 7 of them in Poland. Everywhere the hurricane caused floods, power lines cut, damage to roofs of houses, and uprooted trees.

Annual losses from typhoons cause significant damage to the economies of several Asian countries. Most economically underdeveloped countries have great difficulty repairing the damage caused by typhoons. Of the 25-30 typhoons that appear every year over the western part of the Pacific Ocean, the Sea of ​​Japan and Primorsky Krai, i.e. on the territory of Russia, come out in different years from one to four typhoons, bringing a sharp deterioration in the weather and causing significant economic damage.

All of them arise over the ocean to the northeast of the Philippines. The average duration of a typhoon is 11 days, and the maximum is 18 days. The minimum pressure observed in such tropical cyclones varies widely: from 885 to 980 hPa, but when typhoons enter our territory, the pressure in their centers rises to 960-1005 hPa.

The maximum daily precipitation reaches 400 mm, and the wind speed is 20-35 m/s. In 2000, four typhoons hit the territory of Primorye, one of which - BOLAVEN - turned out to be the most destructive: 116 settlements, damaged 196 bridges and about 2000 km highways. A total of 32,000 people were affected and one person died. Economic damage amounted to more than 800 million rubles.

Forecasting hurricanes and typhoons, detecting their origin, tracking their trajectories is the most important task of the meteorological services of many countries, primarily the USA, Japan, China, and Russia. To solve these problems, space monitoring methods, modeling of atmospheric processes, synoptic forecasts are used.

To reduce damage from hurricanes and typhoons, primarily in terms of human casualties, methods of warning, evacuation, adaptation of industrial processes, engineering protection of coasts, buildings, and structures are used.

The destructive power of cyclones, typhoons and hurricanes lies primarily in the colossal wind speed, which affects the land and causes waves at sea. The destructive effect of cyclones is associated with the turbulent, vortex movement of air particles. Destruction during cyclones is also associated with low pressure in their center-eye. Extremely heavy rain showers, which cause floods, are also detrimental.

Tropical cyclones occur in tropical latitudes. They are distinguished by a clear concentration of energy in a small space, large pressure drops and high wind speeds. Annually over earth's surface 70-80 tropical cyclones are formed in total, but only a small part of them reaches destructive power, and of these, in turn, only a part captures the land.

According to the definitions, the wind speed in tropical cyclones should exceed 34 m/s. However, most of them are characterized by speeds much higher than 50 m/s, and speeds of more than 100 m/s (that is, more than 360 km/h) have been recorded.

Consider the structure of a tropical cyclone. The diameter of its inner part - the eye, where calm reigns and the sky is clear, most often fluctuates between 10 and 20 km. The eye is surrounded by a so-called wall where the winds reach top speed. In the wall, not only vortex, but also ascending air movements are carried out. Part of the air in the marginal zones of the cyclone is drawn in, the other part is released.

Tropical cyclones are born all the time. This happens near the equator, most often in the band between 5 and 10 ° north or south latitude.

Cyclones most often move at a speed of 30-50 km/h. In the Atlantic and Pacific oceans, they first move to the west, then turn to the north and northeast. Over land, their tracks become irregular: they turn, turn back and cross their track. Such cyclones are especially dangerous. They are called wanderers. Cyclone Flora, which in 1963 devastated the eastern part of Cuba, also belonged to this type. East Asian cyclones (typhoons) first move due west and turn north near land. Cyclones in the Bay of Bengal move in a northwesterly direction directly over land.

The energy of tropical cyclones is colossal, it is difficult to accurately calculate it. It is believed that the cyclone medium strength releases approximately the same amount of energy as 50,000 atomic bombs with a capacity of 30 kilotons. The ocean and moist air are needed by the cyclone as energy suppliers. The vapor rises, the pressure at altitude drops, and the vapor condenses. This condensation is the main source of energy that keeps the cyclone alive.

Hurricanes these are winds of force 12 on the Beaufort scale, i.e. winds exceeding 32.6 m/s (117.3 km/h).

Hurricanes occur during the passage of deep cyclones and represent the movement air masses(wind) at great speed. During a hurricane, the air speed exceeds 32.7 m/s (more than 118 km/h). Sweeping over the earth's surface, the hurricane breaks and uproots trees, rips off roofs and destroys houses, power lines and communications, buildings and structures, disables various equipment. As a result of a short circuit in the power grid, fires occur, the supply of electricity is interrupted, the operation of objects stops, and other harmful consequences may occur. People may find themselves under the rubble of destroyed buildings and structures. Fragments of destroyed buildings and structures and other objects flying at high speed can cause serious injuries to people.

Reaching the highest stage, the hurricane goes through 4 stages in its development: tropical cyclone, baric depression, storm, intense hurricane.

Hurricanes typically move at 15 km per hour along a westerly path and often pick up speed, usually veering toward north pole on the line 20-30 degrees northern latitude. But often they follow a more complex and unpredictable pattern. In any case, hurricanes can cause enormous destruction and tremendous loss of life.

Modern methods of weather forecasting make it possible to warn the population of a city or an entire coastal region about an impending hurricane (storm) in a few hours or even days, and the civil defense service can provide necessary information about the possible situation and actions in the current conditions.

When propagating over the sea, a hurricane causes huge waves with a height of 10-12 m or more, damages or even leads to the death of the ship.

After a hurricane, NASF, together with the entire able-bodied population of the facility, carry out rescue and emergency recovery work; rescue people from overwhelmed protective and other structures and provide assistance to them, restore damaged buildings, power and communication lines, gas and water pipelines, repair equipment, and carry out other emergency recovery work.

Tornadoes.

A tornado is one of the cruel, destructive phenomena of nature. According to V.V. Kushina, tornado - this is not wind, but a “trunk” of rain twisted into a thin-walled pipe, which rotates around its axis at a speed of 300-500 km / h. Due to centrifugal forces, a vacuum is created inside the pipe and the pressure drops to 0.3 atm. If the wall of the "trunk" of the funnel breaks, bumping into an obstacle, then outside air rushes into the funnel. Pressure drop 0.5 atm. accelerates the air secondary flow to speeds of 330 m/s (1200 km/h) and more, i.е. to supersonic speeds. Tornadoes are formed in an unstable state of the atmosphere, when the air in the upper layers is very cold, and in the lower layers it is warm. There is an intense air exchange, accompanied by the formation of a vortex of great strength.

Such whirlwinds arise in powerful thunderclouds and are often accompanied by thunderstorms, rain, and hail. Obviously, it cannot be said that tornadoes arise in every thundercloud. As a rule, this happens on the verge of fronts - in the transition zone between warm and cold air masses. It is not yet possible to predict tornadoes, and therefore their appearance is unexpected.

The tornado does not live long, since rather soon the cold and warm air masses mix, and thus the reason supporting it disappears. However, even in a short period of its life, a tornado can cause enormous damage.

Until now, the tornado is in no hurry to reveal its other secrets. So, there are no answers to many questions. What is a tornado funnel? What gives its walls a strong rotation and tremendous destructive power? Why is the tornado stable?

It is not only difficult to study a tornado, but also dangerous - upon direct contact, it destroys not only the measuring equipment, but also the observer.

Comparing descriptions of tornadoes (tornadoes) of the past and present centuries in Russia and other countries, one can see that they develop and live according to the same laws, but these laws have not been fully elucidated and the behavior of a tornado seems unpredictable.

During the passage of tornadoes, of course, everyone hides, runs, and people are not up to observing, and even more so measuring the parameters of tornadoes. The little that we managed to find out about the internal structure of the funnel is due to the fact that the tornado, breaking away from the ground, passed over the heads of people, and then it was possible to see that the tornado is a huge hollow cylinder, brightly lit inside by the brilliance of lightning. A deafening roar and buzzing is heard from within. It is believed that the wind speed in the walls of the tornado reaches the sound.

A tornado can suck in and lift up a large portion of snow, sand, etc. As soon as the speed of snowflakes or grains of sand reaches a critical value, they will be thrown out through the wall and can form a kind of case or cover around the tornado. characteristic feature This case-cover is that the distance from it to the wall of the tornado along the entire height is approximately the same.

Meteorological natural disasters are very dangerous, as they entail huge human casualties, a good example of this is the hurricane Katrina in the United States, are associated with the destruction of buildings, structures, cause great damage to humanity, which, of course, is a global problem.

In the homeland of hurricanes, in the tropics, air masses are very hot and saturated with water vapor - the temperature of the ocean surface at these latitudes reaches twenty-seven to twenty-eight degrees Celsius. As a result, powerful ascending currents of air arise and the release of the solar heat stored by it and the condensation of the vapors contained in it. The process develops and grows, it turns out a kind of giant pump - into the funnel formed at the place of origin of this pump, neighboring masses of the same warm and steamy air, and thus the process spreads further and in breadth, capturing more and more new areas on the surface of the ocean.

When you pour water from the bathtub through the drain hole, a whirlpool is formed. Approximately the same thing happens with the air rising up at the place where the cyclone originates - it begins to rotate.

The giant air pump continues to work, more moisture condensing on its funnel-shaped top, more heat being released. (American meteorologists have calculated that over a million tons of water can be lifted up in one day - in the form of steam, which continuously saturates the surface layer of the atmosphere; the energy released during condensation in just ten days would be enough for such a highly industrialized state, like the USA, for six years!). It is believed that a moderate cyclone releases approximately the same amount of energy as 500,000 atomic bombs with the power dropped over Hiroshima. Atmospheric pressure in the center of the nascent cyclone and on its outskirts becomes unequal: there, in the center of the cyclone, it is much lower, and a sharp pressure drop is the cause of strong winds that soon develop into hurricanes. In a space with a diameter of three hundred to five hundred kilometers, the strongest winds begin their frantic whirlwind.

Having arisen, cyclones begin to move at an average speed of 10-30 km / h, sometimes they can hover over the area for a while.

Cyclones (ordinary and tropical) are large-scale eddies with a diameter: ordinary from 1000 to 2000 km; tropical from 200 to 500 km and height from 2 to 20 km.

Air masses move in the area of ​​the cyclone in a spiral, twisting towards its center (counterclockwise in the northern hemisphere, vice versa in the southern) at a speed of:

Ordinary no more than 50-70 km / h;

Tropical 400-500 km/h

In the center of the cyclone, the air pressure is lower than at the periphery, which is why, moving in a spiral, the air masses tend to the center, where they then rise up, giving rise to strong clouds.

If in the center:

Normal cyclone air pressure compared to atmospheric (760 mm r.s.) is 713-720 mm r.s.;

Then in the center of a tropical cyclone, the pressure drops to 675 mm r.s.

There is an area at the center of a tropical cyclone low pressure With high temperature, with a diameter of 10-40 km, where calm reigns - typhoon eye.

Annually for globe At least 70 tropical cyclones arise and fully develop.

When a tropical cyclone (typhoon, hurricane) approaches the coast, it carries huge masses of water in front of it. Storm Shaft accompanied by strong rains and tornadoes. It swoops down on coastal areas, destroying everything in its path.

Example

In 1970, a typhoon. which broke through the mouth of the Ganges River (in India) flooded 800,000 km 2 of the coast. Had a wind speed of 200-250 m/s. The sea wave reached a height of 10 m. About 400,000 people died.

Today there are modern methods forecasting tropical cyclones (typhoons, hurricanes). Every suspicious cloud formation where it did not occur is photographed by meteorological satellites from space, weather service planes fly to the "eye of the typhoon" to get accurate data. This information is put into computers to calculate the path and duration of a tropical cyclone (typhoon, hurricane) and notify the population in advance of the danger.

Hurricane

A hurricane is a wind force of 12 points (up to 17 points) on the Beaufort scale, i.e. at a speed of 32.7 m/s (more than 105 km/h) and reaches up to 300 m/s (1194 km/h)

Hurricane- a strong small-scale atmospheric vortex in which the air rotates at a speed of up to 100 m/s. It is shaped like a pillar (sometimes with a concave axis of rotation) with funnel-shaped extensions at the top and bottom. The air rotates counterclockwise and simultaneously rises in a spiral, drawing in dust, water, and various objects. A hurricane on land is called storm and on the sea storm.

The main characteristics of hurricanes are:

Wind speed;

Ways of movement;

Dimensions and construction;

Average duration of actions.

most important characteristic hurricanes is wind speed. The table below (on the Beaufort scale) shows the dependence of the wind speed and the names of the modes. average speed hurricane movement in Ukraine 50-60 km/h.

Hurricanes vary greatly in size. Usually, the width of the zone of catastrophic destruction, which can be measured in hundreds of kilometers, is taken as its width. The hurricane front reaches a length of up to 500 km. Hurricanes occur at any time of the year, but are more frequent from July to October. In the remaining 8 months they are rare, their paths are short.

The average duration of a hurricane is 9-12 days. In Ukraine, hurricanes do not last long, from a few seconds to several hours.

A hurricane is almost always clearly visible; when it approaches, a strong hum is heard.

Hurricanes are one of the most powerful forces of the elements. In terms of their harmful effects, they are not inferior to such terrible natural disasters as earthquakes. This is due to the fact that they carry enormous energy. Its amount released by a hurricane of average power in one hour is equal to the energy nuclear explosion at 36 Mgt.

A hurricane carries a triple threat to people who find themselves in its path. The most destructive are wind, waves and rain.

Often, showers accompanied by a hurricane are much more dangerous than the hurricane itself, especially for those people who live on or near the coast. A hurricane creates waves up to 30 m high on the coast, can cause showers, and later cause an epidemic, for example, a hurricane storm tide, which coincided with the usual one, caused a giant flood on the coast of India in 1876, during which the wave rose by 12-13 m About 100,000 people drowned and almost as many died from the consequences of a ferocious epidemic.

When a hurricane propagates over the sea, it causes huge waves 10-12 meters or more high, damaging or even leading to the death of the ship.

The greatest danger during a hurricane is objects lifted from the ground and spun to great speed. Unlike storms, a hurricane travels in a narrow band, so it can be avoided. You just need to determine the direction of its movement and move in the opposite direction.

Hurricane wind 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 on utility and energy networks in production . There were cases when hurricane winds destroyed dams and dams, which led to large floods, threw trains off the rails, tore bridges from supports, knocked down factory pipes, and threw ships onto land.

AT tropical zone in latitudes from 5 to 25 ° in both hemispheres, tropical cyclones are observed, which have tremendous destructive power. It has been calculated that if all the energy of only one tropical cyclone were turned into electrical energy, then it would be enough for all mankind for several years.

Tropical cyclones are small cyclones, averaging 100 to 200 miles in diameter, with very low pressure at the center (very deep cyclones).
They are accompanied by powerful, descending to the ground, thunderclouds, hurricane-force winds, heavy downpours, huge ocean waves. Even the largest modern ships find it very difficult to fight a hurricane, and often this struggle ends in the death of the ship.

The pressure in the central region of a tropical cyclone is on average 960 - 970 mbar, but sometimes 900 mbar or less. The difference in pressure between the center and periphery of tropical cyclones per 1° distance (111 km), the so-called baric gradient, is 30–40, and sometimes more than 100 mbar. while in ordinary cyclones it usually does not exceed 20 - 25 mbar.
For this reason, the wind speed in tropical cyclones usually reaches hurricane force up to 50 - 60 m/s and more. Tropical cyclones arise only over the oceans and seas. The reasons for their occurrence have not yet been fully elucidated. Currently, there are several theories of the formation of tropical cyclones.

According to one of them, cyclones arise from ascending currents of warm and humid air, which are accompanied by the release of huge amounts of latent thermal energy as a result of condensation of water vapor.
Another theory explains this phenomenon by the interaction of air masses of the northern and southern hemispheres in the zone of convergence of the trade winds. But one thing is absolutely clear that tropical cyclones arise in such oceanic areas and in those seasons of the year when the sea surface temperature is the highest and exceeds 26-27 °. The structure of tropical cyclones is still not entirely clear.
While hurricane winds, heavy showers and thunderstorms are raging around, in the center, with an average diameter of 10-15 miles, there is an area of ​​clear calm weather - the “eye of the storm”

The most dangerous is the right (in terms of movement) half of the cyclone in the northern hemisphere, and in the southern hemisphere - the left. Here, the wind speed often reaches 65 m / s and the speed of individual squally gusts is 100 m / s or more

Most often, tropical cyclones in the northern hemisphere are observed from August to September, and in the southern hemisphere in the Pacific Ocean from January to July, in the Indian Ocean from November to April. The exception is the northern part of the Indian Ocean, where tropical cyclones are more common from May to December

Tropical cyclones that originate in the western Pacific are called typhoons. Atlantic Ocean- Antilles hurricanes, in the northern part of the Indian Ocean - cyclones, and in the south - orkans, off the coast of Australia - "willy-willy" Unlike ordinary cyclones, tropical ones move from east to west, and some, crossing tropical latitudes, change direction and go in the northern hemisphere to the northeast, and in the southern hemisphere to the southeast.
If, with the transition to middle latitudes, a tropical cyclone encounters a polar front, then it significantly increases in size and turns into an ordinary deep cyclone with a warm and cold front. On average, about 20 - 23 cyclones are observed per year in the Pacific Ocean, 12 - 13 in the Atlantic, and about 15 in the Indian. The paths of tropical cyclones, with rare exceptions, are constant.
The speed of movement of tropical cyclones at first is small, but in well-developed ones it reaches 15-20 miles per hour or more. The duration of the existence of tropical cyclones is on average 8 - 10 days.

When a tropical cyclone passes into the sea, a characteristic, growing noise appears. Black or red wisps of broken clouds quickly sweep across the sky. A huge black cloud is approaching with great speed, covering the entire sky. The wind intensifies, becomes gusty, squalls begin to fly incessantly.
Thunder rumbles incessantly of great strength Huge dazzling lightning often pierces the ensuing darkness. A very strong wind creates giant waves with great strength. Rainwater streams mix in the air with spray and foam from the waves, visibility is reduced to a few meters. This state of weather and sea can last for many hours.

When the center of a tropical cyclone (“eye of the storm”) passes, for 20-30 minutes the wind subsides to calm, clears up, you can see a blue or starry sky, but the sea does not decrease.
The waves here converge from all directions and create an extremely steep and chaotic crowd, very dangerous for ships ( standing waves about 40 m long). As you move away from the center of the cyclone, the excitement takes on a more ordered, regular character.

After passing through the "eye of the storm", the barometer makes a quick jump upwards, and a flurry of hurricane force again flies from the opposite rhumb.
General character weather becomes the same as before the passage of the center of the cyclone. Sometimes tornadoes are observed in a tropical cyclone - small eddies with a diameter of several hundred meters at a speed of up to 20 - 25 miles per hour. The wind in such a whirlwind has a colossal speed of 200 - 250 m/sec.
Distinctive feature tornadoes - a funnel-shaped lowering of clouds with a long tail downward in the form of a trunk, the end of which sometimes touches the water. Tornadoes have tremendous destructive power.

The danger of tropical cyclones for navigation is further aggravated by the fact that, due to their relatively small size, they cannot always be detected on maps by weather forecasters.
For this reason, ships at sea cannot receive timely warnings about the origin and path of the hurricane. In this regard, local signs and radio equipment for detecting approaching tropical cyclones are of particular importance.
When information about tropical cyclones is transmitted by radio, they are given the female names Vera, Diana, Nancy, Charlotte, and others. In the old days, tropical cyclones were given the names of the ships that discovered them.

As already mentioned in the “Waves on the Sea” section, the direction of the swell can be used to judge the position of the center of the cyclone, and the change in its direction indicates the direction of the cyclone. The appearance of a swell that does not come from the direction from which the wind is blowing or was blowing earlier is a sign of the approach of a tropical cyclone.

When a tropical cyclone approaches, atmospheric pressure changes dramatically, so observing barometer and barograph readings is one of important factors timely detection and prediction of an approaching tropical cyclone. Atmospheric pressure at a distance of 120 - 150 miles from the center of a tropical cyclone begins to gradually fall, but its daily course is still noticeably preserved.
Further, with the approach of the center of a tropical cyclone at a distance of 60 - 110 miles, the daily pressure pattern is completely disrupted, the pressure drops sharply (pa 13 - 20 mbar per hour), the pressure drop stops only when the "eye of the storm" passes.
After passing through the center of a tropical cyclone, the pressure begins to increase rapidly at first, and then, with the removal of the center, more slowly, and finally reaches the normal value for the given region.

The approach of a tropical cyclone, sometimes at very large distances (up to 1500 miles). It is preceded by the appearance of cirrus filamentous clouds with curved ends, which are best observed at sunrise or sunset. If these clouds appear to converge at one point, then with a high probability we can assume that at a distance of about 500 miles from the ship, in the region of convergence of these clouds, the center of a tropical cyclone is located.
At a distance of about 300 miles from the center of a tropical cyclone, the direction of movement of cirrus clouds often coincides with the direction of movement of the cyclone. Cirrus clouds are not always an absolute sign of the approach of a tropical cyclone, but their appearance should not be ignored.
At a distance of 500 - 600 miles from the center of the cyclone, cirrocumulus clouds are usually observed, and at a distance of 200 - 250 miles, heaps of gloomy powerful cumulonimbus clouds, the view of the sky at this moment is menacing.
The appearance of cumulonimbus clouds is often preceded by the appearance on the horizon of a small, noticeably increasing and rapidly moving dark cloud - a "bull's eye".
At a distance of 200 to 250 miles from the center of a tropical cyclone, a good sign of its approach is the appearance of broken cumulus clouds.

Initially, these are single clouds, but as the center of the cyclone approaches, their number increases, they become denser and gradually turn into rain clouds.
At the same time, squalls with showers pass. The movement of broken-cumulus clouds indicates the direction of movement of the center of a tropical cyclone. If you face towards the movement of these clouds, then the center of the tropical cyclone will be located to the right of the vessel.

In 100 - 150 miles from the center of a tropical cyclone, heavy rain begins, which is clearly visible on the ship's radar screen.
Under normal radar observation, a band of heavy rain is detected at the limit of the radar range; this helps determine the vessel's position relative to the center of the tropical cyclone.
At 10 to 15 miles from the center the rain stops and the clouds disperse. After the passage of the central region of the tropical cyclone, the clouds again close and a shower of the same intensity begins as before the passage of the center of the cyclone, but the duration of the rain is somewhat shorter. With the removal of a tropical cyclone, rain clouds turn into cumulus and the rain stops.

When a tropical cyclone approaches, as well as when a normal cyclone approaches, halos and crowns around the sun and moon are sometimes observed.

The purple-red color of the dawn is a sign of the approach of a tropical cyclone. And the evening dawn is held for a long time and remains red until the end, without turning into yellow. At the same time, the shadow of the earth is clearly visible from the opposite side, the edge of which has an orange color.
Such a dawn can be observed 2 - 3 days before the onset of a cyclone. Sometimes tropical cyclones are preceded by sunrises and sunsets, at which the sky takes on a fiery or copper-red color with a variety of hues.

A day or more before the onset of a tropical cyclone, there is a clear sky, calm or light wind, a significant increase in temperature, absolute and relative humidity of the air (there is a strong closeness) and a violation of their daily course, from the beginning of the onset and further passage of the cyclone, there is a rapid drop in air temperature.

At night, from the side of an approaching tropical cyclone, strong reflections of lightning (lightning) are often visible.

During radio reception, frequent discharges or a continuous crackle are heard, which intensifies as the cyclone approaches.

Separate bright spots appear on the radar screen, which are large droplets in the atmosphere

Wind direction in various parts of a tropical cyclone changes in the same way as in cyclones of temperate latitudes, differing only in a much faster transition from one rhumb to another. Wind direction is a good indication of the location of the center of a tropical cyclone.
By changing the direction of the wind, one can judge in which half of the cyclone relative to its path the ship is located (see "Ship avoidance of tropical and deep cyclones").

An increase in wind speed is a sign of the approach of a tropical cyclone, but this sign appears too late.