Natural phenomena of meteorological origin. Dangerous atmospheric phenomena (signs of approach, damaging factors, preventive measures and protective measures) Dangerous natural phenomena of meteorological origin

Planet Earth is shrouded in a multi-kilometer layer of atmosphere (air). The air is in constant movement. This movement is primarily due to different temperatures of air masses, which is associated with uneven heating of the Earth's surface and water by the Sun, as well as different atmospheric pressure. The movement of air masses relative to the earth and water surfaces is called by the wind. The main characteristics of wind are speed, direction of movement, force.

Wind speed is measured by a special device - an anemometer

The direction of the wind is determined by the part of the horizon from which it blows.

Wind strength is determined in points. A point system for assessing wind strength was developed in the 19th century by the English admiral F. Beaufort. It is named after him.

Table 12

Beaufort scale

Wind is an indispensable participant and the main driving force behind many emergencies. Depending on its speed, the following catastrophic winds are distinguished.

Hurricane- this is an extremely fast and strong, often of enormous destructive force and significant duration, movement of air at a speed of over 117 km/h, lasting several (3-12 or more) days.

During hurricanes, the width of the zone of catastrophic destruction reaches several hundred kilometers (sometimes thousands of kilometers). The hurricane lasts 9-12 days, causing a large number of casualties and destruction. The transverse size of a tropical cyclone (also called a tropical hurricane or typhoon) is several hundred kilometers. The pressure in hurricanes drops much lower than in an extratropical cyclone. At the same time, the wind speed reaches 400-600 km/h. 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 hurricane's center as spiral bands of precipitation swirl around the eye of the hurricane. The heaviest precipitation and the strongest winds are associated with the eye wall.

The eye, an area 20-50 km in diameter, is located in the center of the hurricane, where skies are often clear, winds are light, and pressure is lowest.

The eye wall is a ring of cumulonimbus clouds swirling around the eye. The heaviest precipitation and the strongest winds are found here.

Spiral bands of precipitation are bands of powerful convective showers directed towards the center of the cyclone.

The destructive effect of hurricanes is determined by wind energy, i.e. speed pressure ( q), proportional to the product of atmospheric air density ( r) per square of the air flow speed ( V)

q= 0,5pV²(kPa)

Tornado (tornado)- an atmospheric vortex that arises in thunderclouds and descends towards land in the form of a dark arm with a vertical curved axis and a funnel-shaped expansion in the upper and lower parts. Much less is known about the origin of tornadoes than about other OHSSs. The nature of tornadoes can be judged only by visual observations of cloud cover and weather conditions, by the nature of the destruction associated with them, and by analysis of aerosynoptic conditions preceding this phenomenon. Most tornadoes are associated with squall lines or active cold fronts with thunderstorms. The most favorable conditions for the formation of tornadoes are located directly on the surface front line, near the Earth's surface (this is a narrow strip about 50 km wide on both sides of the front line). The minimum possible height of tornado nucleation centers is within 0.5 – 1.0 km, and the maximum is up to 3 km from the Earth’s surface. When a tornado originates at a higher level, it is more difficult for it to “break through” the underlying layer of air and reach the surface of the Earth. Typically, a tornado appears visually when a cloud column in the form of a funnel with an appendage resembling an elephant’s trunk breaks off from a thundercloud. 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.

The tornado has a large destructive force. It uproots trees, tears off roofs, sometimes destroys stone buildings and scatters various objects over long distances. Such disasters do not go unnoticed. So, according to chronicles from 1406, “a great storm broke out in Nizhny Novgorod, a whirlwind lifted the team with the horse into the air and carried it away. The next day the cart was found on the other side of the river. Volga. She hung on a tall tree. The horse was dead and the man was missing." The diameter of a tornado over land is about 100-1000 m, sometimes up to 2 km. The apparent height of the “trunk” is 800-1500 m. There are also such cases: in the summer of 1940, in the village of Meshchery, Gorky Region, one day a thunderstorm broke out, and along with the rain, silver coins from the time of Ivan IV fell to the ground - the result of a passing tornado.

It should be noted that a tornado has many names. Depending on the type of surface over which it passes (water or land), it is called a tornado, thrombus or tornado. However, all these phenomena have almost the same nature.

Squalls and tornadoes are local natural phenomena. They appear suddenly (usually in the afternoon), are short-lived (usually observed in one place for several minutes) and cover relatively small areas (from several tens to hundreds square meters). Tornadoes and squalls are the result of processes of all scales, which lead to the accumulation of large reserves of potential energy of air masses in the troposphere, passing beyond short term into the kinetic energy of movement of a large mass of air. Such processes lead to loss of life and significant material destruction.

Squall– a short-term, unexpected sharp increase in wind with a constant change in the direction of its movement for a short time. The wind speed during a squall often reaches 25-30 m/s, which is much higher than the speed of a normal gradient wind. The maximum frequency of squalls is observed in the afternoon and evening hours of the day. They are usually associated with thunderstorms, but are often observed as an independent phenomenon. A squall is a whirlwind with a horizontal axis of rotation. The reason for its occurrence is the movement of air masses under the influence of temperature differences. The duration of the squall ranges from several seconds to tens of minutes. Squalls are often accompanied by precipitation with an intensity of more than 20mm/12 hours and hail.

Rainfall causes intense downward movements. The downward flow of air from upper levels, where the wind is weaker, transfers some motion and kinetic energy downward. This air, entering the lower layers, is slowed down due to friction with the earth's surface and collision with warm air masses lying in front of the front. As a result, a wind shaft is formed, directed in the direction of the movement of the thunderstorm source. A squall has many of the characteristics of a wave in which wind shears are observed in both vertical and horizontal directions.

Storm– continuous strong wind with a speed of 103-120 km/h causing great disturbances at sea and destruction on land. The storm is responsible for the death of dozens of ships every year.

Already at a force of 9 on the Beaufort scale, when the speed is from 20 to 24 m/sec, the wind knocks down dilapidated buildings and rips roofs off houses. It's called a storm. If the wind speed reaches 32 m/sec, it is referred to as a hurricane. The manifestation of a storm as a marine hydrological phenomenon will be discussed in more detail in Chapter 6.

Storm- this is a type of hurricane and storm, air movement at a speed of 62-100 km/h (15-20 m/s). Such a wind is capable of blowing out the top layer of soil over tens and hundreds of square kilometers, transporting millions of tons of fine-grained soil particles and, in deserts, sand through the air over long distances.

The storm lasts from several hours to several days, the width of the front during the storm is several hundred kilometers. The storm causes a large number of casualties and destruction.

Dust (sand) storms can cover vast areas with dust, sand, and earth. In this case, the thickness of the applied layer is tens of centimeters. Crops are destroyed, roads are filled up, water bodies and the atmosphere are polluted, and visibility deteriorates. There are known cases of people and caravans dying during a storm.

During a storm, a huge amount of snow rises into the air (blizzards), which leads to huge snowfalls, blizzards, and snow drifts. Snow storms paralyze traffic, disrupt energy supplies and people's daily activities, and lead to tragic consequences. To avoid an accident during a storm, it is necessary to stop moving and equip a temporary reliable shelter. In order to prevent dust, sand, and snow from getting into your eyes, throat, and ears, you must cover your head with a cloth, breathe through your nose, and use a gauze bandage or handkerchief.

"BORA"– is a specific wind for Russia. This strong, cold, northeast wind most often blows on the Black Sea coast in the area between Novorossiysk and Anapa. Wind speed can reach 40 m/s.

In 1975, Hurricane Bora caused enormous damage to the city of Novorossiysk. The wind speed reached 144 km/h. 18 years later, the same hurricane washed ashore 3 ships, there were casualties

It is known that the earth’s crust, together with part of the upper mantle, is not a monolithic shell of the planet, but consists of several large blocks (plates) with a thickness of 60 to 200 km. In total there are 7 huge slabs and dozens of smaller slabs. Top part Most plates have both continental and oceanic crust, that is, these plates contain continents, seas and oceans.

The plates lie on a relatively soft, plastic layer of the upper mantle, along which they slowly move at a speed of 1 to 6 cm per year. Neighboring plates move closer together, diverge, or slide relative to each other. They “float” on the surface of the plastic layer of the upper mantle, like pieces of ice on the surface of water.

As a result of the movement of plates, complex processes constantly occur in the bowels of the Earth and on its surface. For example, when plates collide with the oceanic crust, deep-sea depressions (trenches) can appear, and when plates that form the base of the continental crust collide, mountains can form. When two plates approach the continental crust, their edges, along with all the sedimentary rocks accumulated on them, are crushed into folds, forming mountain ranges. With the onset of critical overloads, the folds shift and tear. The ruptures occur instantly, accompanied by a shock or a series of shocks that have the nature of impacts. The energy released during the rupture is transmitted through the earth's crust in the form of elastic seismic waves and leads to earthquakes.

The boundary areas between lithospheric plates are called seismic belts. These are the most restless, mobile areas of the planet. The majority of active volcanoes are concentrated here and at least 95% of all earthquakes occur.

Thus, geological natural phenomena are associated with the movement of lithospheric plates and changes occurring in the lithosphere.

Dangerous geological phenomenon- an event of geological origin or the result of geological processes occurring in earth's crust under the influence of various natural or geodynamic factors or their combinations that have or may have damaging effects on people, farm animals and plants, economic objects and the natural environment.

Dangerous geological natural phenomena include earthquakes, volcanic eruptions, landslides, and landslides.

Meteorological natural phenomena

Dangerous meteorological phenomenon- natural processes and phenomena that occur in the atmosphere under the influence of various natural factors or their combinations, which have or may have a damaging effect on people, farm animals and plants, economic objects and the natural environment.

These processes and phenomena are associated with various atmospheric processes, and above all with the processes occurring in the lower layer of the atmosphere - the troposphere. The troposphere contains about 9/10 of the total air mass. Under the influence of solar heat entering the earth's surface and the force of gravity, clouds, rain, snow, and wind are formed in the troposphere.

Air in the troposphere moves in horizontal and vertical directions. Strongly heated air near the equator expands, becomes lighter and rises. There is an upward movement of air. For this reason, a belt of low atmospheric pressure forms near the Earth's surface near the equator. At the poles due to low temperatures the air cools, becomes heavier and sinks. There is a downward movement of air. For this reason, the pressure at the Earth's surface near the poles is high.

In the upper troposphere, on the contrary, above the equator, where ascending air currents predominate, the pressure is high, and above the poles it is low. Air constantly moves from an area of high pressure to an area low blood pressure. Therefore, the air rising above the equator spreads towards the poles. But due to the rotation of the Earth around its axis, the moving air does not reach the poles. As it cools, it becomes heavier and sinks at approximately 30° northern and southern latitudes, forming regions in both hemispheres high pressure.

Large volumes of air in the troposphere with homogeneous properties are called air masses. Depending on the place of formation of air masses, four types are distinguished: equatorial air mass, or equatorial air; tropical air mass, or tropical air; moderate air mass, or temperate air; Arctic (Antarctic) air mass, or Arctic (Antarctic) air.

The properties of these air masses depend on the territories over which they formed. Moving around air masses They retain their properties for a long time, and when they meet, they interact with each other. The movement of air masses and their interaction determine the weather in the places where these air masses arrive. The interaction of various air masses leads to the formation of moving air masses in the troposphere. atmospheric vortices- cyclones and anticyclones.

Cyclone is a flat rising vortex with low atmospheric pressure in the center. The diameter of a cyclone can be several thousand kilometers. The weather during a cyclone is predominantly cloudy with strong winds.

Anticyclone is a flat downward vortex with high atmospheric pressure with a maximum in the center. In an area of high pressure, the air does not rise, but falls. The air spiral unwinds clockwise in the northern hemisphere. The weather during the anticyclone is partly cloudy, without precipitation, and the wind is weak.

The movement of air masses and their interaction are associated with the emergence of dangerous meteorological phenomena that can cause natural disasters. These are typhoons and hurricanes, storms, blizzards, tornadoes, thunderstorms, drought, severe frosts and fogs.

Hydrological natural phenomena

Water on the surface of the Earth is found in oceans and seas, in rivers and lakes, in the atmosphere in a gaseous state and in glaciers in a solid state.

All water on Earth that is not part of rocks is united by the concept of “hydrosphere”. The volume of all water on Earth is so large that it is measured in cubic kilometers. A cubic kilometer is a cube with each edge measuring 1 km, completely filled with water. The weight of 1 km 3 of water is equal to 1 billion tons. The Earth contains 1.5 billion km 3 of water, 97% of which is the World Ocean. Currently, it is customary to divide the World Ocean into 4 separate oceans and 75 seas with bays and straits.

Water is in a constant cycle, and closely interacts with the air shell of the Earth and with the land.

The driving force behind the water cycle is solar energy and gravity.

Under the influence of sunlight, water evaporates from the surface of the ocean and land (from rivers, reservoirs, soil and plants) and enters the atmosphere. Some of the water immediately returns with rain back to the ocean, while some is transported by winds to land, where it falls to the surface in the form of rain or snow. Once on the soil, water is partially absorbed into it, replenishing the reserves of soil moisture and groundwater, and partially flows into rivers and reservoirs. Soil moisture partly passes into plants, which evaporate it into the atmosphere, and partly flows into rivers. Rivers fed by surface and underground waters carry water to the World Ocean, replenishing its loss. Water, evaporating from the surface of the World Ocean, ends up back in the atmosphere, and the cycle closes.

This movement of water between the constituent parts of nature and all parts of the earth's surface occurs constantly and uninterruptedly for many millions of years.

The water cycle in nature, like a closed chain, consists of several links. There are eight such links: atmospheric, oceanic, underground, river, soil, lake, biological and economic. Water constantly moves from one link to another, connecting them into a single whole. In the process of the water cycle in nature, dangerous natural phenomena constantly arise that affect the safety of human life and can lead to catastrophic consequences.

Dangerous hydrological phenomenon- an event of hydrological origin or the result of hydrological processes arising under the influence of various natural or hydrodynamic factors or their combinations, which have a damaging effect on people, farm animals and plants, economic objects and the environment.

Hazardous natural phenomena of a hydrological nature include floods, tsunamis and mudflows.

Biological hazards

Living organisms, including humans, interact with each other and the surrounding inanimate nature. During this interaction, the exchange of substances and energy occurs, there is continuous reproduction, growth of living organisms and their movement.

Among the most dangerous natural phenomena of a biological nature that have an impact significant influence on the safety of human life, there are:

natural fires (forest fires, fires of steppe and grain massifs, peat fires and underground fires of fossil fuels);
infectious diseases of people (single cases of exotic and especially dangerous infectious diseases, group cases of dangerous infectious diseases, epidemic outbreak of dangerous infectious diseases, epidemic, pandemic, infectious diseases of people of unknown etiology);
infectious diseases of animals (single outbreaks of exotic and especially dangerous infectious diseases, enzootics, epizootics, panzootics, infectious diseases of farm animals of unknown etiology);
damage to agricultural plants by diseases and pests (epiphytoty, panphytoty, disease of agricultural plants of unknown etiology, mass spread of plant pests).

Wildfires include forest fires, fires of steppe and grain massifs, and peat fires. The most common are forest fires, which occur annually, causing enormous losses and resulting in casualties.

Forest fires are uncontrolled burning of vegetation that spontaneously spreads throughout the forest area. In dry weather and wind, forest fires cover large areas.

In hot weather, if there is no rain for 15-20 days, the forest becomes a fire hazard. Statistics show that in 90-97% of cases the cause is forest fires is the life activity of people.

Epidemic- widespread spread of an infectious disease among people, significantly exceeding the incidence rate usually recorded in a given territory. The usual (minimal) morbidity rate for a given area is most often isolated cases of diseases that have no connection with each other.

Epizootics- widespread infectious diseases of animals.

Epiphytoty- widespread plant diseases.

The massive spread of infectious diseases among people, farm animals or plants poses a direct threat to the safety of human life and can lead to emergency situations.

Infectious diseases is a group of diseases that are caused by specific pathogens (bacteria, viruses, fungi). The characteristic features of infectious diseases are: contagiousness, i.e. the ability to transmit pathogens from a sick organism to a healthy one; staged development (infection, incubation period, course of the disease, recovery).

Space hazards

The Earth is a cosmic body, a small particle of the Universe. Other cosmic bodies can have a strong influence on earthly life.

Everyone has seen “shooting stars” appear and disappear in the night sky. This meteors- small celestial bodies. We are observing a short-term flash of hot glowing gas in the atmosphere at an altitude of 70-125 km. It occurs when a meteor enters the atmosphere at high speed.

Consequences of the fall of the Tunguska meteorite. Photo 1953

If, during its movement in the atmosphere, the solid particles of the meteor do not have time to completely collapse and burn, then their remains fall to the Earth. This meteorites.

There are also larger celestial bodies that planet Earth can encounter. These are comets and asteroids.

Comets- these are bodies moving quickly in the starry sky solar system, moving in highly elongated orbits. As they approach the Sun, they begin to glow and a “head” and a “tail” appear. The central part of the “head” is called the nucleus. The diameter of the core can be from 0.5 to 20 km. The core is an icy body of frozen gases and dust particles. The “tail” of a comet consists of gas molecules and dust particles evaporated from the nucleus under the influence of sunlight. The length of the “tail” can reach tens of millions of kilometers.

Asteroids- these are small planets, the diameter of which ranges from 1 to 1000 km.

Currently, about 300 cosmic bodies are known that can cross the Earth's orbit. In total, according to astronomers, there are approximately 300 thousand asteroids and comets in space.

Fall of the Sikhote-Alin meteorite

The meeting of our planet with large celestial bodies poses a serious threat to the entire biosphere.

The world around us natural environment constantly changing, processes of metabolism and energy take place in it, and all this, taken together, gives rise to various natural phenomena. Depending on the intensity of manifestation and the power of the processes occurring, these natural phenomena can create a threat to human life and create an emergency situation natural character.

Test yourself

Name the main groups of natural hazards.
List the main natural phenomena of a geological nature and explain the reasons for their occurrence.
What main natural phenomena of a meteorological and hydrological nature do you know? Indicate their interdependence.
Tell us about dangerous natural phenomena of a biological nature. State the reasons for their appearance.

After classes

Ask an adult, look online and keep a safety diary for the main natural phenomena of geological, meteorological, hydrological and biological origin in your area.

Natural disasters.

A natural disaster is a catastrophic natural phenomenon (or process) that can cause numerous casualties, significant material damage and other severe consequences.

Natural disasters include earthquakes, volcanic eruptions, mudflows, landslides, landslides, floods, droughts, cyclones, hurricanes, tornadoes, snow drifts and avalanches, prolonged heavy rains, severe persistent frosts, extensive forest and peat fires. Natural disasters also include epidemics, epizootics, epiphytoties, and the massive spread of forest and agricultural pests.

Over the last 20 years of the 20th century, a total of more than 800 million people (over 40 million people per year) were affected by natural disasters in the world, more than 140 thousand people died, and the annual material damage amounted to more than 100 billion dollars.

Three illustrative examples include: natural disasters in 1995

1) San Angelo, Texas, USA, May 28, 1995: tornadoes and hail hit a city with a population of 90 thousand; The damage caused is estimated at 120 million US dollars.

2) Accra, Ghana, July 4, 1995: The heaviest rainfall in nearly 60 years causes severe flooding. About 200,000 residents lost all their belongings, more than 500,000 more were unable to get into their homes, and 22 people died.

3) Kobe, Japan, January 17, 1995: an earthquake that lasted only 20 seconds killed thousands of people; tens of thousands were injured and hundreds were left homeless.

Natural emergencies can be classified as follows:

1. Geophysical dangerous phenomena:

2. Geological hazards:

3. Marine hydrological hazards:

4. Hydrological hazards:

5. Hydrogeological hazards:

6. Natural fires:

7. Infectious morbidity in people:

8. Infectious disease incidence in farm animals:

9. Damage to agricultural plants by diseases and pests.

10. Meteorological and agrometeorological hazards:

storms (9 - 11 points);

hurricanes and storms (12 - 15 points);

tornadoes, tornadoes (a type of tornado in the form of part of a thundercloud);

vertical vortices;

large hail;

heavy rain (rain);

heavy snowfall;

heavy ice;

severe frost;

severe snowstorm;

extreme heat;

heavy fog;

frosts.

Hurricanes and Storms

Storms are a long-term movement of wind, usually in one direction at high speed. According to their type, they are divided into: snowy and sandy. And according to the wind intensity across the band width: hurricanes, typhoons. Wind movement and speed, intensity is measured on the Beaufort scale in points.

Hurricanes are winds of force 12 on the Beaufort scale, that is, winds whose speed exceeds 32.6 m/s (117.3 km/h).

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

Having reached its highest stage, a hurricane goes through 4 stages in its development: tropical cyclone, pressure depression, storm, intense hurricane. Hurricanes typically form over the tropical North Atlantic, often off the west coast of Africa, and gain strength as they move westward. Large number Incipient cyclones develop similarly, but on average only 3.5 percent of them reach tropical storm stage. Only 1-3 tropical storms, usually located over Caribbean Sea and the Gulf of Mexico, reaching the east coast of the United States every year.

Many hurricanes originate off the west coast of Mexico and move northeast, threatening coastal areas of Texas.

Hurricanes typically last from 1 to 30 days. They develop over overheated ocean areas and transform into supertropical cyclones after a long passage over the cooler waters of the North Atlantic Ocean. Once on the underlying land surface, they quickly extinguish.

The conditions necessary for the formation of a hurricane are completely unknown. There is Project Storms, a US government effort to develop ways to defuse hurricanes at their source. Currently, this complex of problems is being studied in depth. The following is known: an intense hurricane is almost regularly round in shape, sometimes reaching 800 kilometers in diameter. Inside the tube of super-warm tropical air is the so-called “eye” - an expanse of clear blue sky approximately 30 kilometers in diameter. It is surrounded by the “wall of the eye” - the most dangerous and restless place. It is here that the air swirling inward, saturated with moisture, rushes upward. In doing so, it causes condensation and the release of dangerous latent heat - the source of the storm's power. Rising kilometers above sea level, energy is released to the peripheral layers. In the place where the wall is located, rising air currents, mixing with condensation, form a combination of maximum wind force and frantic acceleration.

The clouds extend around this wall in a spiral pattern parallel to the direction of the wind, thus giving the hurricane its characteristic shape and changing the heavy rain at the center of the hurricane to tropical downpour at the edges.

Hurricanes typically move at 15 kilometers per hour along a westerly path and often pick up speed, usually deflecting towards the north pole at a line of 20-30 degrees northern latitude. But they often develop according to a more complex and unpredictable pattern. In any case, hurricanes can cause enormous destruction and staggering loss of life.

Before the approach of hurricane winds, equipment and individual buildings are secured, doors and windows are closed in industrial premises and residential buildings, and electricity, gas, and water are turned off. The population takes refuge in protective or buried structures.

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

The most reliable protection of the population from hurricanes is the use of protective structures (subway, shelters, underground passages, basements of buildings, etc.). At the same time, in coastal areas it is necessary to take into account the possible flooding of low-lying areas and choose protective shelters in elevated areas.

A hurricane on land destroys buildings, communication and power lines, damages transport communications and bridges, breaks and uproots trees; when spread over the sea, it causes huge waves 10-12 m or more in height, damaging or even leading to the death of a ship.

After a hurricane, the formations, together with the entire working population of the facility, carry out rescue and emergency restoration work; rescue people from blocked protective and other structures and provide them with assistance, restore damaged buildings, power and communication lines, gas and water supply lines, repair equipment, and carry out other emergency restoration work.

In December 1944, 300 miles east of the island. Luzon (Philippines) ships of the US 3rd Fleet found themselves in an area near the center of the typhoon. As a result, 3 destroyers sank, 28 other ships were damaged, 146 aircraft on aircraft carriers and 19 seaplanes on battleships and cruisers were broken, damaged and washed overboard, over 800 people died.

From hurricane winds unprecedented strength and gigantic waves that hit the coastal areas of East Pakistan on November 13, 1970, affected a total of about 10 million people, including approximately 0.5 million people killed or missing.

Tornado

A tornado is one of the cruel, destructive phenomena of nature. According to V.V. Kushina, a tornado is not the wind, but a “trunk” of rain twisted into a thin-walled pipe, which rotates around an 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, encountering an obstacle, then the outside air. Pressure drop 0.5 atm. accelerates the secondary air flow to speeds of 330 m/s (1200 km/h) or more, i.e. up to supersonic speeds. Tornadoes are formed when the atmosphere is in an unstable state, when the air is in upper layers very cold, but warm in the lower parts. Intense air exchange occurs, accompanied by the formation of a vortex of enormous force.

Such vortices arise in powerful thunderclouds and are often accompanied by thunderstorms, rain, and hail. Obviously, it cannot be said that tornadoes occur in every thundercloud. As a rule, this happens on the edge 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.

A tornado does not live long, since pretty soon the cold and warm air masses mix, and thus the cause that supports it disappears. However, even over a short period of its life, a tornado can cause enormous destruction.

natural meteorological atmospheric

- heavy rains. Most often (95-100% probability) they fall in the Carpathians and predetermine mudflows, avalanches and shifts;
- strong blizzards, snowfalls. Blizzards are associated with the movement of cyclones from the south and southwest. Poor visibility during snowstorms and heavy snow drifts create many difficulties, both in the operation of different types of transport and in work on construction sites;
- strong wind (from maximum speed over 25 m/s), squalls, tornadoes. Most often, such wind is observed in mountainous areas, as well as in the Donetsk, Volyn and Podolsk uplands;
- fog is an accumulation of water droplets or ice crystals suspended in the ground layer of the atmosphere, which impairs horizontal visibility at a distance of up to 1 km. Based on intensity, fogs are classified as very strong (visibility is less than 50 m), strong (50-200 m), moderate (201-500 m) and weak (501-1000 m);
- A thunderstorm is a complex atmospheric phenomenon that is accompanied by electrical discharges, significant precipitation and often hail. Thunderstorms belong to dangerous phenomena, the effects of which can cause significant damage to activities and even threaten human life;
- Hail - round or irregularly shaped ice particles that fall mostly during the warm season from powerful cumulonimbus clouds with significant vertical movement and high moisture content. Hail causes significant damage agriculture: damages crops, vineyards, fruit trees, over large areas. The amount of damage depends on the size of the hailstones, their density and the intensity of the fall;
- A squall is a short-term sharp increase in wind speed, which forms in cumulonimbus clouds, is accompanied by a change in wind direction and is observed during thunderstorms and showers. During a squall, trees break, crops are destroyed, buildings are destroyed, and sometimes even human casualties are possible;
- A tornado is a vortex of a complex structure with a vertical axis, which descends from the lower limit of powerful cumulonimbus clouds to the earth's surface. In the form of a light or dark funnel, which rotates and is characterized by significant wind speeds, powerful downward and upward flows, a significant difference in atmospheric pressure, from the center of the funnel to the periphery, which together creates the extreme energy of a tornado;
- A dust storm or black storm is a phenomenon that is caused by the transfer of large amounts of dust or sand by strong winds and is accompanied by reduced visibility. A dust storm occurs during dry weather and when wind speed increases to values at which parts of dust or sand are blown out of the underlying surface.

Ministry of Education of the PMR

Transnistrian State University named after. T. G. Shevchenko

Department of Life Safety and Fundamentals of Medical Knowledge

Topic: "Meteorological and agrometeorological hazards"

Supervisor:

Dyagovets E. V.

Executor:

Student of group 208

Rudenko Evgeniy

Tiraspol

PLAN

Introduction

Chapter 1. Metrological and agrometrological hazards

1. Heavy fogs

Blizzards and snow drifts

Tender and icy crusts

Rules of behavior for the population during snow drifts and actions to eliminate their consequences

Chapter 2. Description of icing in Kamensky, Rybnitsky and Dubossary regions

Conclusion

References

fog blizzard snow drift liquidation

Introduction

The spontaneous actions of the forces of nature, which are not yet fully subject to human control, cause enormous damage to the state’s economy and population.

Natural disasters are natural phenomena that cause extreme situations and disrupt the normal functioning of people and the operation of facilities.

Natural disasters usually include earthquakes, floods, mudflows, landslides, snow drifts, volcanic eruptions, landslides, droughts, hurricanes, storms, fires, especially massive forest and peat fires. Industrial accidents are also dangerous disasters. Accidents at oil, gas and chemical industries pose a particular danger. . Natural disasters occur suddenly and are of an extreme nature. They can destroy buildings and structures, destroy valuables, disrupt production processes, and cause the death of people and animals.

By the nature of their impact on objects, individual natural phenomena may be similar to the impact of some damaging factors of a nuclear explosion and other means of enemy attack.

Each natural disaster has its own characteristics, the nature of the damage, the volume and scale of destruction, the magnitude of disasters and human casualties. Each leaves its mark on the environment in its own way.

Advance information makes it possible to carry out preventive work, prepare forces and means, and explain to people the rules of behavior.

The entire population must be prepared to act in extreme situations, to participate in disaster relief work, to be able to master the methods of providing first aid to victims.

Natural disasters are dangerous natural phenomena or processes of geophysical, geological, hydrological, atmospheric and other origins of such a scale that cause catastrophic situations characterized by a sudden disruption of the life of the population, damage and destruction of material assets, damage and death of people and animals.

Natural disasters can occur either independently of each other or in conjunction: one of them can lead to the other. Some of them often arise as a result of human activity that is not always reasonable (for example, forest and peat fires, industrial explosions in mountainous areas, during the construction of dams, foundation (development) of quarries, which often leads to landslides, snow avalanches, glacier collapses, etc. p.).

The true scourge of humanity are earthquakes, floods, extensive forest and peat fires, mudflows and landslides, storms and hurricanes, tornadoes, snow drifts, and icing. Over the last 20 years of the 20th century, a total of more than 800 million people (over 40 million people per year) were affected by natural disasters in the world, more than 140 thousand people died, and the annual material damage amounted to more than 100 billion dollars.

Illustrative examples include three natural disasters in 1995: San Angelo, Texas, USA, May 28, 1995: tornadoes and hail hit a city of 90,000 people; The damage caused is estimated at 120 million US dollars.

Accra, Ghana, July 4, 1995: The heaviest rainfall in nearly 60 years causes severe flooding. About 200,000 residents lost all their property, more than 500,000 more were unable to get into their homes, and 22 people died.

Kobe, Japan, January 17, 1995: An earthquake that lasted only 20 seconds killed thousands; tens of thousands were injured and hundreds were left homeless.

Natural emergencies can be classified as follows:

1.Geophysical hazards:

2.Geological hazards:

.Marine hydrological hazards:

.Hydrological hazards:

.Hydrogeological hazards:

.Natural fires:

.Infectious morbidity in humans:

.Infectious morbidity of farm animals:

.Damage to agricultural plants by diseases and pests.

.Meteorological and agrometeorological hazards:

storms (9 - 11 points);

hurricanes and storms (12 - 15 points);

tornadoes, tornadoes (a type of tornado in the form of part of a thundercloud);

vertical vortices;

large hail;

heavy rain (rain);

heavy snowfall;

heavy ice;

severe frost;

severe snowstorm;

extreme heat;

heavy fog;

frosts.

CHAPTER 1. Metrological and agrometrological hazards

A dangerous hydrometeorological phenomenon (HEP) is understood as a phenomenon that, due to its intensity, duration or time of occurrence, poses a threat to human safety and can also cause significant damage to sectors of the economy. In this case, hydrometeorological phenomena are assessed as critical events when critical values of hydrometeorological values are reached. Dangerous hydrometeorological phenomena have an adverse impact on the production and economic activities of society. According to the UN, in the last decade 1991-2000. More than 90% of people who become victims of natural hazards die from severe meteorological and hydrological events.

1. Heavy fogs

Fog in general is an aerosol with a droplet-liquid dispersed phase. It is formed from supersaturated vapors as a result of condensation. Atmospheric fog is a suspension of small water droplets or even ice crystals in the ground layer. The predominant droplet sizes are 5-15 microns. Such droplets can be maintained in suspension by rising air currents at a speed of 0.6 m/s. When the number of such droplets in 1 dm3 of air reaches 500 or more, horizontal visibility in the surface layer of the atmosphere drops to 1 km and below. That's when meteorologists talk about fog. The mass of water drops in 1 m3 (this value is called water content) is small - hundredths of a gram. A denser fog, naturally, has a higher water content - up to 1.5 and 2 g per 1 m.

Characteristics of fogs . The fog water content indicator is used to characterize fogs; it means total weight water droplets per unit volume of fog. The water content of fogs usually does not exceed 0.05-0.1 g/m3, but in some dense fogs it can reach 1-1.5 g/m3. In addition to water content, the transparency of fog is affected by the size of the particles that form it. The radius of fog droplets typically ranges from 1 to 60 µm. Most drops have a radius of 5-15 microns at positive air temperatures and 2-5 microns at negative temperatures.

Fogs are a more common occurrence in coastal areas of the seas and oceans, especially on elevated shores.

Where do water droplets come from in the air? They are formed from water vapor. When the earth's surface cools due to thermal radiation (thermal radiation), the adjacent layer of air also cools. The content of water vapor in the air may be higher than the limit for a given temperature. In other words, the relative humidity becomes 100% and excess moisture condenses into droplets. Fog formed by this (by the way, the most common) mechanism is called radiation. Radiation fog forms most often in the second half of the night; in the first half of the day it dissipates, and sometimes turns into a thin layer of low stratus clouds, the height of which does not exceed 100-200 m. Radiation fogs occur especially often in lowlands and wetlands.

Advective fog is formed by the horizontal movement (advection) of warm, moist air over a cooled surface. Such fogs are common in oceanic areas with cold currents, for example, near Vancouver Island, as well as off the coast of Peru and Chile; you are in the Bering Strait and along the Aleutian Islands; off the west coast South Africa"over the Bengal, cold current and in the Newfoundland region, where the Gulf Stream meets the cold Labrador Current; on east coast Kamchatka above the Kamchatka Cold Current and northeast of Japan, where the cold Kuril Current and the warm Kuroshio Current meet. Similar fogs are often observed on land when warm and humid oceanic or sea air invades the cooled territory of a continent or large island.

Ascension fogs appear in warm, moist air as it rises along mountain slopes. (As you know, in the mountains, the higher, the colder.) An example is the island of Madeira. At sea level there is practically no fog here. The higher you go in the mountains, the greater the average annual number of foggy days. At an altitude of 1610 m above sea level, there are already 233 such days. However, in the mountains, fogs are practically inseparable from low clouds. Therefore, on average, there is much more fog at mountain weather stations than at plains. El Paso Station in Colombia, at an altitude of 3624 m above sea level, experiences an average of 359 foggy days per year. On Elbrus at an altitude of 4250 m, on average there are 234 days a year with fog, on the top of Mount Taganay in the Southern Urals - 237 days. Among stations close to sea level, the largest average number of days with fog per year (251) is observed in the American state of Washington - on Tatush Island, and in our country - on the Sakhalin Cape Terpeniya (121) and on the Kamchatka Cape Lopatka (115). One of the largest centers of fog formation is located in the Republic of Zaire. There are many swamps on its territory, the prevailing equatorial-tropical climate here is characterized by high temperatures and air humidity, the country is located in a vast basin with weakened air circulation in the surface layers of the atmosphere. Thanks to such conditions, the southwestern part of the republic experiences 200 or more days with fog annually. Of course, when they talk about a foggy day, this does not mean that the fog lasts around the clock. The longest average duration of fog is observed in our country at Cape Terpeniya and is 11.5 hours. But if we introduce another indicator of “fog” - the average annual number of hours with fog, then the record here is held by the mountain weather station Fichtelberg (GDR) - 3881 hours. This is just less than half the number of hours in a year. The longest was a three-month dry fog over Europe in 1783, caused by intense activity of Icelandic volcanoes. In 1932, humid fog at the American airport of Cincinnati at an altitude of 170 m above sea level lasted 38 days. Fogs may become more frequent in individual months year. In July on all Patience there can be up to 29 days with fog, in August on the Kuril Islands. - up to 28 days, in January-February on the mountain peaks of Crimea and the Urals - up to 24 days.

Fogs significantly complicate transport communications due to reduced horizontal visibility, so this atmospheric phenomenon is of particular concern to airport dispatchers, sea and river port workers, pilots, ship captains, and car drivers. Over the past 50 years, 7,000 people have died on Earth from fogs.

Difficulties associated with aviation and flights.

Wind speed during radiation fog does not exceed 3 m/sec. The vertical thickness of fog can vary from several meters to several tens of meters; rivers, large landmarks and lights are clearly visible through it. Visibility near the ground may deteriorate to 100 degrees or less. Flight visibility deteriorates sharply when entering a layer of fog on landing. Flight above radiation fog does not present any particular difficulties, since in most cases it is located in spots and makes it possible to maintain visual orientation. However, in the cold season, such fogs can occupy significant areas and, merging with the overlying stratus clouds, persist for several days. In this case, fog can pose a serious obstacle to flight operations.

Low-level flight through a front that has formed fog is quite difficult, especially if the fog layer merges with overlying frontal cloud and the fog zone is wide. If there is fog at the front, it is more advisable to fly above the upper limit of the fog.

Fog in mountainous areas occurs when air rises and cools along windward slopes or when clouds formed in another area move in and cover higher elevations. In the absence of clouds above the ridge, flying above such fog does not present any serious difficulties.

Frosty mists - a common occurrence at airfields, where they occur during takeoff and landing, when taxiing aircraft, and when operating vehicles. In these cases, visibility on the runway can deteriorate to several hundred meters, while visibility around the airfield at this time remains excellent.

Fog is usually called fog when the horizontal visibility range does not exceed 1 km. With a visibility range of 1 to 10 km, the accumulation of tiny drops of water or ice crystals in the ground layer of air should be called not fog but haze. When flying over a layer of haze, the pilot may not be able to see the ground, while the plane is clearly visible from the ground. With a thinner layer of haze, the pilot will see the ground directly below him, but when descending and entering a layer of haze, he may not be able to see the airfield, especially when flying against the sun. In light winds, it is better to plant in such a direction that the sun remains behind. The upper boundary of the haze in the presence of a retarding layer (inversion, isotherm) is usually sharply defined and can sometimes be perceived as a second horizon.

Flight cancellations due to heavy fog. On November 22, 2006, an unprecedented fog occurred in Moscow. Sheremetyevo and Vnukovo airports found themselves in such a thick veil that air traffic controllers had to redirect two dozen aircraft to alternate airfields.

Difficulties arising on roads.

Fogs, as is known, when they occur, create a thick veil over the surface of the earth, interfering with road and rail traffic. This causes difficulty in movement, slowdown in movement, as well as car accidents in which many people die.

Examples of accidents on highways. A major traffic accident occurred on September 11, 2006 at the entrance to Krasnodar. Due to heavy fog, 62 cars collided at the entrance to the city from Rostov-on-Don. As a result of the car accident, one person died, 42 people were hospitalized with injuries of varying severity.

In Istanbul on November 17, 2006, more than a hundred cars collided due to fog. 33 people were injured, doctors fear for the lives of at least two of the victims. A major accident happened on the highway leading from Istanbul to the city of Edirne, which is located near the Bulgarian border.

Difficulties associated with sea navigation.

With light fog, visibility is reduced to 1 km, with moderate fog - up to hundreds of meters, and with heavy fog - up to several tens of meters. And then the ships temporarily anchor and the lighthouse sirens turn on. Sometimes, due to fog, ships stumble upon rocks or icebergs. Yes, maybe

Example. The Turkish sea straits of the Bosphorus and Dardanelles are closed to navigation due to thick fog, visibility in the straits has decreased to 200 meters.

The most famous tragedy at sea associated with fog. Tita ́ nick is an English Olympic class liner, the largest passenger ship in the world at the time of its construction, owned by the White Star Line company. During the first voyage on April 14, 1912, it collided with an iceberg due to thick fog and sank after 2 hours 40 minutes. Of the 2,223 passengers and crew members, 706 survived. The Titanic disaster became legendary and was one of the largest shipwrecks in history.

Protection from fog at sea. The small vessel navigation system is designed for the navigation of small vessels in conditions of limited optical visibility (night, fog, snow, rain, high smoke, etc.) or its absence, when control and navigation is carried out by visual control, or according to other optical or IR data -sensors is difficult or impossible.

Harm to agriculture.

Fogs have a negative impact on the development of agricultural crops. When there is fog, the relative humidity reaches 100%, so frequent fogs in the warm season favor the proliferation of plant pests, the appearance of bacteria, fungal diseases, etc. When harvesting grain, fog contributes to the accumulation of moisture in the grain and straw; damp straw is wound around the working parts of the combine, the grain is poorly threshed and a significant part of it goes into chaff. Wet grain needs longer drying, otherwise it may germinate. Frequent fogs at the end of summer and autumn make harvesting potatoes difficult, as the tubers dry out slowly. In winter, fogs “eat up” the snow, and if a sharp cold snap occurs after this, an ice crust forms.

. Blizzards and snow drifts

A blizzard (blizzard) is the transfer of snow by a strong wind over the surface of the earth. The amount of snow transported is determined by the wind speed, and the areas where snow accumulates are determined by its direction. During the process of snowstorm transport, snow moves parallel to the surface of the earth. In this case, the bulk of it is transported in a layer less than 1.5 m high. Loose snow rises and is carried by the wind at a speed of 3-5 m/s or more (at a height of 0.2 m).

There are ground snowstorms (in the absence of snowfall), high snowstorms (with wind only in a free atmosphere) and general snowstorms, as well as saturated snowstorms, that is, carrying the maximum amount of snow possible at a given wind speed, and unsaturated snowstorms. The latter are observed when there is a lack of snow or when the snow cover is very strong. The solid flow rate of a saturated bottom snowstorm is proportional to the third degree of wind speed, and that of an aerial snowstorm is proportional to its first degree. At a wind speed of up to 20 m/s, snowstorms are classified as weak and normal, at a speed of 20-30 m/s - as strong, at high speed- to very strong and super strong (in fact, these are already storms and hurricanes). Weak and normal snowstorms last up to several days, stronger ones - up to several hours.

Snow accumulation during blizzard transport is many times higher than the accumulation of snow that is observed as a result of snowfalls in calm weather.

Snow deposition occurs as a result of decreased wind speed near ground obstacles. The shape and size of the reserves are determined by the shape and size of the obstacles and their orientation relative to the direction of the wind.

In Russia, heavy snow drifts primarily affect the snow-rich regions of the Arctic, Siberia, the Urals, the Far East and the North of the European part. In the Arctic, snow cover lasts up to 240 days a year and reaches 60 cm, in Siberia, respectively, up to 240 days and 90 cm, in the Urals - up to 200 days and 90 cm, in the Far East - up to 240 days and 50 cm, in the north European part of Russia - up to 160 days and 50 cm.

An additional negative effect during snow drifts occurs due to severe frost, strong winds during snowstorms and icing. The consequences of snow drifts can be quite severe. They are able to paralyze the operation of most modes of transport, stopping the transportation of people and goods. Wheeled vehicles cannot normally drive on smooth snowy roads if the snow depth exceeds half the diameter of the wheel. People who find themselves isolated in the area due to snow drifts are at risk of frostbite and death, and in blizzard conditions they lose their orientation. In case of heavy drifts, small settlements may be completely cut off from supply lines. The work of utility and energy enterprises is becoming more difficult. If drifts are accompanied by severe frosts and winds, power supply, heat supply, and communication systems may fail. The accumulation of snow on the roofs of buildings and structures in excess of excess loads leads to their collapse.

In snow-covered areas, the design and construction of buildings, structures and communications, especially roads, should be carried out taking into account the reduction of snow accumulation.

To prevent drifts, snow barriers are used from pre-prepared structures or in the form of snow walls, shafts, etc. Fences are built in snow-hazardous areas, especially along railways and important highways. Moreover, they are installed at a distance of at least 20 m from the edge of the road.

A preventive measure is to notify authorities, organizations and the population about the forecast of snowfalls and blizzards.

To guide pedestrians and vehicle drivers caught in a snowstorm, milestones and other signs are installed along the roads. In mountainous and northern regions, ropes are stretched on dangerous sections of trails, roads, and from building to building. Holding on to them, in snowstorm conditions, people navigate the route.

In anticipation of a snowstorm, construction and industrial sites are securing crane booms and other structures that are not protected from the effects of wind. Stop work in open areas and at heights. The mooring of ships in ports is being strengthened. Reduce vehicle access to routes to a minimum.

When a threatening forecast is received, the forces and means intended to combat drifts and carry out emergency recovery work are brought into readiness.

The main measure to combat snow drifts is clearing roads and territories. First of all, railways and highways, airfield runways, station tracks of railway stations are cleared of drifts, and they also provide assistance to vehicles caught in a disaster on the way.

In the most severe cases, paralyzing the vital functions of entire settlements, the entire working population is involved in snow clearing.

Simultaneously with clearing drifts, they organize continuous weather observation, search for and release from snow captivity of people and vehicles, assistance to victims, regulation of traffic and transport, protection and restoration of life support systems, delivery of emergency cargo by special snow-resistant transport to blocked settlements, protection of livestock facilities . If necessary, partial evacuation of the population is carried out and special routes of public transport are organized in columns, as well as the work of educational institutions and institutions is stopped.

Blizzards and the snow drifts they create are possible once every few decades in the subtropics of Asia, North Africa, USA, but are especially common in areas of stable snow cover. Here, the volume of snow transport during the winter through one meter of snowstorm front is usually measured in tens, and in some places - thousands of cubic meters; The thickness of drifts on the roads of Scandinavia, Canada, and the northern USA exceeds 5 m.

In the European part of Russia, the average number of days with a blizzard is 30-40, the average duration of a blizzard is 6-9 hours. Dangerous blizzards make up about 25%, especially dangerous ones - about 10% of their total number. Every year throughout the country there are on average 5-6 severe snowstorms that can paralyze railways and roads, cut off communication and power lines, etc.

3. Snow and ice crusts

Snow and ice crusts are formed when snow sticks and water droplets freeze on various surfaces. The adhesion of wet snow, which is most dangerous for communication and power lines, occurs during snowfalls and air temperatures in the range from 0° to +3°C, especially at temperatures of +1 -3°C and winds of 10-20 m/s. The diameter of snow deposits on the wires reaches 20 cm, weight 2-4 kg per 1 m. Wires break not so much under the weight of snow as from wind load. Under such conditions, a slippery snow slab forms on the road surface, paralyzing traffic almost in the same way as an icy crust. Such phenomena are typical for coastal areas with mild, wet winters (western Europe, Japan, Sakhalin, etc.), but are also common in inland areas at the beginning and end of winter.

When rain falls on frozen ground and when the surface of the snow cover becomes wet and subsequently freezes, ice crusts called glaze are formed. It is dangerous for grazing animals; for example, in Chukotka in the early 80s, black ice caused mass deaths of deer. The type of icy conditions refers to the phenomenon of icing of berths, offshore platforms, and ships due to the freezing of splashes of water during a storm. Icing is especially dangerous for small ships whose decks and superstructures are not raised high above the water. Such a ship can accumulate a critical ice load in a matter of hours. Every year, about ten fishing vessels around the world die from this, and hundreds find themselves in a risky situation. Splash ice on the banks of the Okhotsk and Japanese seas reach a thickness of 3-4 m, greatly interfering with economic activity in the coastal strip.

When supercooled drops of fog freeze on various objects, ice and frost crusts form, the former - at an air temperature range from 0 to -5 ° C, less often to -20 ° C, the second - at a temperature of -10-30 ° C, less often to -40 °C.

The weight of ice crusts can exceed 10 kg/m (up to 35 kg/m on Sakhalin, up to 86 kg/m in the Urals). Such a load is destructive for most wire lines and for many masts. The recurrence of ice is highest where there is frequent fog at air temperatures from 0 to -5°C. In Russia, in some places it reaches tens of days a year.

The impact of ice on the economy is most noticeable in Western Europe, the USA, Canada, Japan, and in the southern regions former USSR and is generally depressing in nature. Emergencies occur occasionally. For example, in February 1984 in the Stavropol Territory, ice and wind paralyzed roads and caused accidents on 175 high-voltage lines; their normal operation resumed only after 4 days. When there is ice in Moscow, the number of car accidents triples.

4. Rules of behavior for the population during snow drifts and actions to eliminate their consequences

The winter manifestation of the elemental forces of nature is often expressed by snow drifts as a result of snowfalls and blizzards.

Snowfalls, the duration of which can be from 16 to 24 hours, greatly affect the economic activities of the population, especially in rural areas. The negative impact of this phenomenon is aggravated by blizzards (blizzards, snowstorms) during which visibility sharply deteriorates and transport links are interrupted, as well as intercity traffic. Snowfall with rain at low temperatures and hurricane winds creates conditions for icing of power lines, communications, contact networks, electric vehicles, roofs of buildings, various types of supports and structures, causing their destruction.

With the announcement of a storm warning - a warning about possible snow drifts - it is necessary to limit movement, especially in rural areas, to create the necessary supply of food, water and fuel at home. In some areas, with the onset of winter, it is necessary to string ropes along the streets between houses to help pedestrians navigate in a strong snowstorm and overcome strong winds.

Snow drifts pose a particular danger to people caught on the road, far from human habitation. Snow-covered roads and loss of visibility cause complete disorientation of the area. When traveling by road, you should not try to overcome snow drifts; you must stop, completely close the car blinds, and cover the engine on the radiator side. If possible, the car should be installed in the windy direction. From time to time you need to get out of the car and shovel the snow so as not to be buried under it. In addition, a car not covered with snow is a good reference point for the search group. The car engine must be periodically warmed up to prevent it from freezing. When warming up the car, it is important to prevent exhaust gases from flowing into the cabin (body, interior); for this purpose, it is important to ensure that the exhaust pipe is not covered with snow. If there are several people on the road together (in several cars), it is advisable to get everyone together and use one car as a shelter; The engines of other vehicles must be drained of water. Under no circumstances should you leave your car shelter: in heavy snowfall (blizzard), landmarks that seem reliable at first glance can be lost after a few tens of meters. In rural areas, upon receipt of a storm warning, it is necessary to prepare the required quantities of feed and water for animals kept on farms. Livestock kept on distant pastures in urgently transported to the nearest shelters, pre-equipped in folds of the terrain or to stationary camps.

With the formation of ice, the scale of the disaster increases. Ice formations on the roads make it difficult, and in very rough terrain, completely stop work road transport. The movement of pedestrians is hampered, and collapses of various structures and objects under load become a real danger. In these conditions, it is necessary to avoid staying in dilapidated buildings, under power and communication lines and near their supports, under trees.

In mountainous areas, after heavy snowfalls, the risk of avalanches increases. The population is notified of this danger by various warning signals installed in places of possible avalanches and possible snow avalanches. These warnings should not be neglected; their recommendations must be strictly followed. To combat snow drifts and icing, civil defense formations and services are involved, as well as the entire working population of the given area, and, if necessary, neighboring areas. Snow removal work in cities is primarily carried out on the main transport routes, and the work of life-supporting energy, heat and water supply facilities is being restored. Snow is removed from the road surface in the leeward direction. They widely use engineering equipment equipped by formations, as well as snow-removal equipment at sites. All available transport, loading equipment and the population are involved in carrying out the work.

CHAPTER 2. Description of icing in Kamensky, Rybnitsky and Dubossary regions

Over three thousand settlements in Ukraine, especially the Vinitsa region, as well as northern Transnistria, suddenly lost light, heat and communications as a result of the violence of the elements on the night of November 26-27. As a result of the sudden cold snap, trees, poles, and wires, wet from prolonged rains, were instantly covered with a thick layer of ice and collapsed due to gravity and wind gusts of 18-20 meters per second. Even some antenna masts of the Transnistrian television and radio center "Mayak" did not survive.

According to preliminary estimates, about 25% of all PMR forests, which had been cultivated for decades, died. The raging elements spared the city of Dubossary itself. Literally a few meters from the head station that supplies the entire city, it froze, otherwise Dubossary would have been deprived of heat and light for a long time.

The picture is different on a district scale. 370 high-voltage power line supports and 80 low-voltage power lines were destroyed. 12 transformers were damaged. According to preliminary data, the damage caused to regional power grid enterprises alone amounted to 826 billion rubles. The material losses of TG Telecom are estimated at 72.7 billion rubles. Total - almost 900 billion rubles.

Kamensky district, as the northernmost, suffered the most from natural disaster. The disaster damaged about 2.5 thousand hectares of the state forest fund. This accounts for 50% to 70% of forested areas. Over 150 km were disabled. power lines, 2880 power poles are littered. The gardens were badly damaged. For several days the regional center was left without heat and light. A day and a half without water.

In the Mayak village of the Grigoriopol region, the disaster swept away concrete power line supports like matches. The radio antenna, which was propped up by the clouds in cloudy weather, collapsed. To repair it, approximately up to 400 thousand USD will be needed.

The village of Mayak, the villages of Gyrton, Glinnoe, Kamarovo, Kolosovo, Makarovka, Kotovka, Pobeda, Krasnaya, Bessarabia, Frunzovka, Veseloe, and Kipka were left without electricity.

A heavy anticyclone left the elements on the approaches to Tiraspol.

CONCLUSION

There are serious reasons to believe that the scale of the impact of disasters and catastrophes on the social, economic, political and other processes of modern society and their drama have already exceeded the level that made it possible to treat them as local failures in the measured functioning of state and public structures. The threshold of system adaptation, which allows the system (in this case, society) to absorb deviations from the acceptable parameters of life and at the same time maintain its qualitative content, has apparently been passed in the twentieth century.

Before man and society in the 21st century. A new goal is emerging more and more clearly - global security. Achieving this goal requires a change in a person’s worldview, value system, individual and social culture. New postulates are needed to preserve civilization and ensure it sustainable development, fundamentally new approaches to achieving comprehensive security. At the same time, it is very important that there should be no dominant problems in ensuring security, since their consistent solution cannot lead to success. Security problems can only be solved comprehensively.

The surface of the Earth will continuously change under the influence of natural processes. Landslides will occur on unstable mountain slopes, high and low water in the rivers will continue to alternate, and storm tides will begin to flood the sea coasts from time to time, and there will be fires. Man is powerless to prevent natural processes themselves, but he has the power to avoid casualties and damage.

It is not enough to know the patterns of development of catastrophic processes, to predict crises, to create disaster prevention mechanisms. It is necessary to ensure that these measures are understood by people, demanded by them, and go into everyday life, being reflected in politics, production, and human psychological attitudes. Otherwise, the state and society will face the “Cassandra effect,” which is almost always mentioned by eyewitnesses of major disasters: many people do not follow warnings, ignore warnings about danger, do not take steps to save themselves (or take erroneous actions).

REFERENCES

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.Newspaper "Transnistria". Issue from 10/30/00 - 12/30/00