Ministry of Education of the PMR

Pridnestrovian 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 208 group

Rudenko Evgeny

Tiraspol

PLAN

Introduction

Chapter 1. Metrological and agrometrological hazards

1. Strong fogs

Blizzards and snowdrifts

Tender and icy crusts

Rules of behavior of the population in case of snow drifts and actions to eliminate their consequences

Chapter 2

Conclusion

Bibliography

fog blizzard snow drift liquidation

Introduction

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

Natural disasters are such natural phenomena that cause extreme situations, disrupt the normal life of people and the operation of objects.

Natural disasters usually include earthquakes, floods, mudflows, landslides, snowdrifts, volcanic eruptions, landslides, droughts, hurricanes, storms, fires, especially massive, forest and peat. Dangerous disasters are, in addition, industrial accidents. Of particular danger are accidents at the enterprises of the oil, gas and chemical industries. . Natural disasters occur suddenly and are of an extreme nature. They can destroy buildings and structures, destroy valuables, disrupt production processes, and cause death of people and animals.

In terms of the nature of their impact on objects, individual natural phenomena can be similar to the impact of certain damaging factors of a nuclear explosion and other means of attack by the enemy.

Each natural disaster has its own characteristics, the nature of 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, to alert forces and means, to explain to people the rules of conduct.

The entire population should be ready to act in extreme situations, to participate in the elimination of natural disasters, to be able to master the methods of providing first aid to the victims.

Natural disasters are hazardous natural phenomena or processes of geophysical, geological, hydrological, atmospheric and other origin of such magnitude that cause catastrophic situations characterized by a sudden disruption of the life of the population, damage and destruction of material values, defeat and death of people and animals.

Natural disasters can occur both independently of each other and in interconnection: one of them can lead to another. Some of them often arise as a result of not always reasonable human activity (for example, forest and peat fires, industrial explosions in mountainous areas, during the construction of dams, laying (development) of quarries, which often leads to landslides, snow avalanches, glacial collapses, etc.). P.).

Earthquakes, floods, extensive forest and peat fires, mudflows and landslides, storms and hurricanes, tornadoes, snow drifts, and icing are the real scourge of mankind. Over the last 20 years of the 20th century, more than 800 million people in the world suffered from natural disasters (over 40 million people a year), more than 140 thousand people died, and the annual material damage amounted to more than 100 billion dollars.

Good examples are 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 almost 60 years caused severe flooding. About 200,000 residents lost all their possessions, more than 500,000 more could not get into their homes, and 22 people died.

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 hazards:

2.Geological hazards:

.Marine hydrological hazards:

.Hydrological hazards:

.Hydrogeological hazards:

.Natural fires:

.Infectious morbidity in humans:

.Infectious incidence of farm animals:

.The defeat of agricultural plants by diseases and pests.

.Meteorological and agrometeorological hazards:

storms (9 - 11 points);

hurricanes and storms (12 - 15 points);

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

vertical vortices;

large hail;

heavy rain (shower);

heavy snowfall;

heavy ice;

severe frost;

strong blizzard;

heatwave;

heavy fog;

frosts.

CHAPTER 1. Metrological and agrometrological hazards

A dangerous hydrometeorological event (HH) is understood as a phenomenon that, by its intensity, duration or time of occurrence, poses a threat to people's safety, and can also cause significant damage to sectors of the economy. At the same time, hydrometeorological phenomena are assessed as OH when critical values ​​of hydrometeorological values ​​are reached. Dangerous hydrometeorological phenomena have an adverse impact on the production and economic activities of the company. According to the UN, in the last decade 1991-2000. more than 90% of the people who became victims of natural hazards died from severe meteorological and hydrological events.

1. Strong fogs

Fog is generally 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 surface layer. The prevailing droplet sizes are 5-15 microns. Such droplets can be kept in suspension by ascending 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, the horizontal visibility in the surface layer of the atmosphere drops to 1 km or less. 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, of course, is characterized by a higher water content - up to 1.5 and 2 g per 1 m.

Mist Characteristics . The water content of fog is used to characterize fogs, it indicates the total mass of 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 the fog is affected by the size of the particles forming it. The radius of fog droplets usually ranges from 1 to 60 µm. Most of the drops have a radius of 5-15 microns at a positive air temperature and 2-5 microns at a negative temperature.

Fog is a more frequent occurrence in the coastal regions 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 is cooled due to thermal radiation (thermal radiation), the layer of air adjacent to it is also cooled. The content of water vapor in the air in this case may be higher than the limit for a given temperature. In other words, the relative humidity becomes 100% and the excess moisture condenses into droplets. Fog formed by this (by the way, the most common) mechanism is called radiation. Radiation fog is formed most often in the second half of the night; in the first half of the day it dissipates, and sometimes passes into a thin layer of low stratus clouds, the height of which does not exceed 100-200 m. Especially often, radiation fogs occur in lowlands and wetlands.

Advective fog is formed by the horizontal movement (advection) of warm, moist air over a cooled surface. Such fogs are frequent in oceanic regions with cold currents, for example, near Vancouver Island, as well as off the coast of Peru and Chile; you the Bering Strait and along the Aleutian Islands; off the western coast of South Africa "over the cold Bengal current and in the Newfoundland region, where the Gulf Stream meets the cold Labrador current; on the east coast of Kamchatka over the cold Kamchatka 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 chilled territory of a continent or a large island.

Climbing fogs appear in warm and humid air as it rises along the slopes of mountains. (As you know, in the mountains - the higher, the colder.) An example is the island of Madeira. There is practically no fog here at sea level. The higher 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. True, in the mountains, fogs are practically inseparable from low clouds. Therefore, at mountain weather stations, on average, there is much more fog than on the plains. At El Paso Station in Colombia, at 3,624 meters above sea level, there are an average of 359 foggy days per year. On Elbrus at an altitude of 4250 m, on average, there are 234 days with fog a year, 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 US state of Washington - on Tatush Island, and in our country - on Cape Patience (121) in Sakhalin and Cape Lopatka (115) in Kamchatka. One of the largest centers of fog formation is located in the Republic of Zaire. There are many swamps on its territory, the equatorial-tropical climate prevailing 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. Due to such conditions, 200 or more foggy days are observed annually in the southwestern part of the republic. Of course, when people talk about a foggy day, this does not mean that the fog stays around the clock. The longest average duration of fog is observed in our country at Cape Patience and is 11.5 hours. But if we introduce another indicator of "nebula" - the average annual number of hours with fog, then the Fichtelberg mountain weather station (GDR) holds the record here - 3881 hours. This is slightly less than half the number of hours per year. The longest was a three-month dry fog over Europe in 1783, caused by the intense activity of Icelandic volcanoes. In 1932, humid fog at the American Cincinnati airport at an altitude of 170 m above sea level lasted 38 days. Fogs can become more frequent in certain months of the year. In July, all Patience 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 the Crimea and the Urals - up to 24 days.

Fog significantly complicates transport communication due to a decrease in 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 the activity of fogs.

Difficulties associated with aviation and flights.

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

Flying at low altitudes across a foggy front is quite difficult, especially if the fog layer merges with: the overlying frontal cloud and the fog zone is wide. In the presence of fog at the front, it is more expedient 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 elsewhere move in and obscure the hills. In the absence of clouds over the ridge, flying above such fog presents no serious difficulties.

frosty mists - a frequent occurrence at airfields, where they occur during takeoff and landing, while taxiing aircraft, during vehicle operation. In these cases, the visibility on the runway may deteriorate to several hundred meters, while around the airfield at this time, excellent visibility is maintained.

It is customary to call fog when the range of horizontal visibility does not exceed 1 km. With a visibility range of 1 to 10 km, the accumulation of the smallest drops of water or ice crystals in the surface layer of air should not be called fog, but haze. When flying over a layer of darkness, the pilot may not see the ground, while the aircraft 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 the haze layer, he may not see the airfield, especially when flying against the sun. In light winds, landing is best done in such a direction that the sun remains behind. The upper boundary of haze in the presence of a delaying layer (inversion, isotherm) is usually sharply defined and can sometimes be perceived as a second horizon.

Cancellation of flights due to heavy fog. In Moscow on November 22, 2006 there was an unprecedented fog. Sheremetyevo and Vnukovo airports were in such a dense veil that the dispatchers had to redirect two dozen aircraft to alternate airfields.

Difficulties encountered on the roads.

Fogs, as you know, when they arise, create a thick veil over the surface of the earth, interfering with road and rail traffic. In this case, there is a difficulty in movement, a slowdown in movement, as well as car accidents in which many people die.

Examples of road accidents. A major traffic accident occurred on September 11, 2006 at the entrance to Krasnodar. Due to heavy fog at the entrance to the city from Rostov-on-Don, 62 cars collided. As a result of a 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 maritime 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, the sirens of the lighthouses turn on. Sometimes, due to fog, ships stumble upon rocks, or icebergs. Yes, maybe

Example. The Turkish sea straits Bosphorus and Dardanelles are closed for navigation due to thickened 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 steamship in the world at the time of its construction, owned by the White Star Line. During the first voyage on April 14, 1912, she collided with an iceberg due to thick fog and sank after 2 hours and 40 minutes. Of the 2223 passengers and crew members, 706 survived. The Titanic disaster became legendary and was one of the largest shipwrecks in history.

Fog protection at sea. The navigation system for small craft is intended for navigation of small-tonnage craft 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, difficult or impossible.

Harm to agriculture.

Fogs adversely affect the development of crops. With fog, relative humidity reaches 100%, so frequent fogs in the warm season favor the reproduction of plant pests, the appearance of bacteria, fungal diseases, etc. When harvesting grain, fog contributes to the accumulation of moisture in grain and straw; damp straw is wound on the working parts of the combine, the grain is poorly threshed and a significant part of it goes into the chaff. Wet grain needs to dry longer, otherwise it may germinate. Frequent fogs in late summer and autumn make it difficult to harvest potatoes, as the tubers dry slowly. In winter, fogs “eat up” the snow, and if after that a sharp cooling occurs, an ice crust forms.

. Blizzards and snowdrifts

A snowstorm (blizzard) is the transfer of snow by a strong wind over the surface of the earth. The amount of snow carried is determined by the wind speed, and the areas of snow accumulation are determined by its direction. In the process of snow drifting, snow moves parallel to the ground. At the same time, most of it is transported in a layer with a height of less than 1.5 m. 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 (in the absence of snowfall), riding (with wind only in a free atmosphere) and general blizzards, as well as saturated blizzards, i.e., carrying the maximum amount of snow possible at a given wind speed, and unsaturated. The latter are observed with a lack of snow or with a high strength of the snow cover. The solid discharge of a saturated blowing blizzard is proportional to the third power of the wind speed, and that of a riding blizzard is proportional to its first power. At a wind speed of up to 20 m/s, blizzards are classified as weak and ordinary, at a speed of 20-30 m/s - as strong, at high speed - as very strong and super-strong (in fact, these are already storms and hurricanes). Weak and ordinary blizzards last up to several days, stronger ones - up to several hours.

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

Snow deposition occurs as a result of a decrease in 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 with respect to the direction of the wind.

In Russia, snowy regions of the Arctic, Siberia, the Urals, the Far East and the North of the European part are primarily subject to heavy snow drifts. 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 wind during snowstorms and icing. The consequences of snow drifts can be quite severe. They are able to paralyze the work of most modes of transport, suspending the transportation of people and goods. Wheeled vehicles cannot normally drive on flat snowy roads if the snowpack is thicker than half the diameter of the wheel. People who find themselves on the ground in isolation due to snow drifts are at risk of frostbite and death, and in the conditions of snowstorms they lose their bearings. With heavy drifts, small settlements can be completely cut off from supply lines. The work of utilities and energy enterprises is becoming more difficult. If drifts are accompanied by severe frosts and winds, power supply, heat supply, and communications systems may fail. The accumulation of snow on the roofs of buildings and structures in excess of excessive loads leads to their collapse.

In snowy areas, the design and construction of buildings, structures and communications, especially roads, should be carried out taking into account the reduction of their snow penetration.

To prevent drifts, snow protection fences are used from structures prepared in advance or in the form of snow walls, shafts, etc. Fences are built in snow-prone directions, especially along railways and important highways. At the same time, 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 public about the forecast of snowfalls and snowstorms.

For orientation of pedestrians and drivers of vehicles caught in a blizzard, milestones and other signs are installed along the roads. In mountainous and northern regions, stretching of ropes is practiced on dangerous sections of trails, roads, from building to building. Holding on to them, in a storm, people navigate the route.

In anticipation of a snowstorm, at construction and industrial sites, crane booms and other structures that are not protected from the effects of the wind are fastened. Stop working in open areas and heights. Strengthen the mooring of ships in ports. Minimize the exit of vehicles on the routes.

Upon receipt of a threatening forecast, the forces and means intended to combat drifts and carry out emergency recovery work are alerted.

The main measure to combat snow drifts is the clearing of roads and territories. First of all, they clear the railway and motorways, runways of airfields, station tracks of railway stations from drifts, and also provide assistance to vehicles caught in a disaster on the way.

In the most severe cases, paralyzing the life of entire settlements, the entire able-bodied population is involved in clearing snow.

Simultaneously with the clearing of drifts, they organize continuous meteorological monitoring, search for and release of people and vehicles from snow captivity, assistance to victims, traffic control and transport wiring, protection and restoration of life support systems, delivery of emergency cargo by special snow-driving vehicles to blockaded settlements, protection of livestock facilities . If necessary, they carry out a partial evacuation of the population and organize special public transport routes in columns, as well as stop the work of educational institutions and institutions.

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

In the European part of Russia, the average number of days with a snowstorm is 30-40, the average duration of a snowstorm is 6-9 hours. Dangerous snowstorms make up about 25%, especially dangerous snowstorms, about 10% of their total number. Every year on the territory of the whole country there are on average 5-6 strongest 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 drops freeze on various surfaces. Wet snow sticking, which is the most dangerous for communication lines and power transmission lines, occurs during snowfalls and air temperatures in the range from 0° to +3°C, especially at a temperature of +1 -3°C and wind of 10-20 m/s. The diameter of snow deposits on wires reaches 20 cm, weight is 2-4 kg per 1 m. Wires are torn not so much under the weight of snow as from wind load. On the roadway under such conditions, a slippery snow run-up forms, paralyzing traffic almost in the same way as an icy crust. Such phenomena are characteristic of coastal regions with mild, wet winters (western Europe, Japan, Sakhalin, etc.), but are also common in inland regions at the beginning and end of winter.

When rain falls on frozen ground and when the surface of the snow cover gets wet and then freezes, ice crusts are formed, called icing. It is dangerous for grazing animals, for example, in Chukotka in the early 80s, sleet caused a mass death of deer. The type of ice cover includes the phenomenon of icing of moorings, offshore platforms, ships due to freezing of water splashes during a storm. Icing is especially dangerous for small vessels, the deck and superstructures of which are not raised high above the water. Such a vessel can gain a critical ice load in a matter of hours. Every year, about ten fishing vessels perish in the world from this, hundreds are in a precarious position. Spatter ice on the shores of the Sea of ​​Okhotsk and the Sea of ​​Japan reaches a thickness of 3-4 m, greatly hindering economic activity in the coastal strip.

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

The weight of ice crusts can exceed 10 kg/m (up to 35 kg/m in Sakhalin, up to 86 kg/m in the Urals). Such a load is devastating for most wire lines and for many masts. Glaze recurrence is highest where fogs are frequent at air temperatures from 0 to -5°C. On the territory of Russia, it sometimes reaches tens of days a year.

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

4. Rules for the behavior of the population in case of 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 snowstorms.

Snowfalls, the duration of which can be from 16 to 24 hours, strongly affect the economic activity of the population, especially in rural areas. The negative impact of this phenomenon is exacerbated by snowstorms (blizzards, snowstorms) in which visibility deteriorates sharply, transport communication is interrupted, as well as intercity. Snowfall with rain at low temperatures and hurricane winds creates conditions for icing of power lines, communications, contact networks, electric transport, 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 the winter period, it is necessary to stretch ropes along the streets, between houses, helping pedestrians navigate in a strong snowstorm and overcome strong winds.

Snow drifts are especially dangerous for people caught on the way, far from human habitation. Snow-covered roads, loss of visibility cause complete disorientation on the ground. When driving by road, you should not try to overcome snow drifts, you must stop, completely close the blinds of the car, cover the engine from the side of the radiator. If possible, the car should be installed with the engine in the windy direction. Periodically, you need to get out of the car, shovel the snow so as not to be buried under it. In addition, a car not covered with snow is a good guide for the search party. The car engine must be periodically warmed up in order to avoid its "freezing". When warming up the car, it is important to prevent exhaust gases from flowing into the cab (body, interior), for this purpose it is important to ensure that the exhaust pipe does not fill up 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; water must be drained from the engines of other vehicles. In no case should you leave the shelter-car: in a heavy snowfall (blizzard), landmarks at first glance, seemingly reliable, can be lost after a few tens of meters. In rural areas, with the receipt of a storm warning, it is necessary to prepare the required amount of food and water for animals kept on farms. Cattle kept on remote pastures are urgently driven to the nearest shelters, previously equipped in the 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 on very rough terrain they completely stop the operation of road transport. The movement of pedestrians is difficult, and the collapse of various structures and objects under load becomes a real danger. Under these conditions, it is necessary to avoid being 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 informed about this danger by various warning signals installed in places of possible avalanches and possible snow falls. These warnings should not be neglected, their recommendations should be strictly followed. To combat snow drifts and icing, civil defense formations and services are involved, as well as the entire able-bodied population of the given region, and, if necessary, neighboring regions. Snow removal works in cities are primarily carried out on the main transport routes, the work of life-supporting energy, heat, and water supply facilities is being restored. Snow is removed from the roadway to the leeward side. They widely use engineering equipment, which is on the equipment of formations, as well as snow-removing equipment of objects. All available transport, loading equipment and the population are involved in the work.

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

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

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

Otherwise, the picture is regional. 370 towers of high-voltage power lines and 80 low-voltage ones were destroyed. Damaged 12 transformers. According to preliminary data, the damage inflicted only on the enterprises of regional power networks amounted to 826 billion rubles. The material losses of Telecom TG are estimated at 72.7 billion rubles. Total - almost 900 billion rubles.

Kamensky district, as the northernmost, suffered the most from the natural disaster. The elements damaged about 2.5 thousand hectares of the state forest fund. This makes up 50% to 70% of forested areas. More than 150 km have been put out of action. power lines, 2880 electrical pylons were blocked. 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 elements swept away the concrete poles of power lines like matches. The radio antenna, which propped up the clouds in cloudy weather, collapsed. For its repair, approximately 400 thousand USD will be needed.

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

A heavy anticyclone left the elements on the outskirts of 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 allowed them to be treated as local failures in the measured functioning of state and public structures. That threshold of systemic adaptation, which allows the system (in this case, society) to absorb deviations from the permissible parameters of life and at the same time maintain its qualitative content, apparently, was passed in the 20th century.

Before the individual and society in the XXI 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 in the preservation of civilization, ensuring its sustainable development, fundamentally new approaches to achieving integrated security. At the same time, it is very important that there should not be 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 surges will flood the sea coasts from time to time, and there will be fires. Man is powerless to prevent the natural processes themselves, but it is in his 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, that they are in demand, that they pass into everyday life, being reflected in politics, production, and the psychological attitudes of a person. 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 danger warnings, do not take steps to save (or make erroneous actions).

BIBLIOGRAPHY

1.Kryuchek N.A., Latchuk V.N., Mironov S.K. Security and protection of the population in emergency situations. M.: NTs EIAS, 2000

.S.P. Khromov "Meteorology and climatology": - St. Petersburg, Gidrometeoizdat, 1983

.Shilov I.A. Ecology Moscow: Higher school, 2000.

.Newspaper "Pridnestrovie". Issue from 30.10.00 - 30.12.00

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Forecasting natural emergencies

Prevention of natural emergencies

Sources of emergencies can be dangerous phenomena and processes in inanimate nature.

Under natural hazards is understood as an event of natural origin or the result of natural processes, which, by their intensity, scale of distribution and duration, can cause a damaging effect on people, economic facilities and the natural environment.

Every year, the economic damage caused by destruction as a result of natural disasters alone exceeds 200 billion US dollars.

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The peculiarity of natural disasters is that they often occur suddenly, little managed and controlled compared to other emergencies.

They can be a source of other emergencies (hepatitis A outbreaks are frequent after floods).

1. Emergencies caused by meteorological processes

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

Dangerous meteorological phenomena include: dangerous winds, thunderstorms, lightning, hail, droughts, downpours, ice, fog.

Dangerous winds

Winds are the cause of many natural disasters.

Cause of the winds- uneven heating of various regions of the rotating Earth.

The equator heats up more, the poles less. The heated air rises, forming an area of ​​low pressure, and the wind must blow from north or south, but here various physical forces intervene, which change the direction of the wind.

The destructive power of the wind depends on its strength. Strong winds pose a danger to humans, animals and the environment.

A strong wind is the movement of air relative to the surface at a speed of 14 m/s.

With further strengthening of the wind, storms, hurricanes, squalls, tornadoes occur.

Storm- air movement at a speed of 14-33 m / s. Duration from several hours to several days. The width of the front is up to hundreds of kilometers. Communication lines, power lines collapse, tree branches break or are uprooted, the roofs of buildings are demolished, etc.

Hurricane- air speed over 32 km/h. Appears suddenly. It carries colossal energy comparable to the energy of a nuclear explosion with a power of 36 Mt. Accompanied by thunderstorms, downpours, hail.

Whirlwind - atmospheric formation with rotational movement of air around a vertical or inclined axis. Can lift light objects into the air.

Tornado- a strong atmospheric vortex with a diameter of 1000 m, in which the air rotates at a speed of 100 m/s. Has great destructive power. Upon reaching the surface of the earth, the tornado becomes like a funnel. Inside the tornado, the air is highly discharged and the structures that are in its path are destroyed with an explosion. He raises large objects and even entire lakes to a great height.

Flurry - short-term increase in wind speed up to 14 m/s. accompanied by a sharp drop in temperature, occur suddenly in cumulonimbus clouds.

In addition to the listed types of winds, there are also dust and snow storms, which also cause significant material damage.

Hazardous atmospheric phenomena (signs of approach, damaging factors, preventive measures and protective measures)

Meteorological and agrometeorological hazards

Meteorological and agrometeorological hazards are divided into:

storms (9-11 points):

hurricanes (12-15 points):

tornadoes, tornadoes;

vertical vortices;

large hail;

heavy rain (shower);

heavy snowfall;

heavy ice;

severe frost;

strong blizzard;

heatwave;

heavy fog;

frosts.

Fog is the concentration of small drops of water or ice crystals in the surface layer of the atmosphere from air saturated with water vapor when it cools. In fog, horizontal visibility decreases to 100 m or less. Depending on the horizontal visibility range, heavy fog (visibility up to 50 m), moderate fog (visibility less than 500 m) and light fog (visibility from 500 to 1000 m) are distinguished.

Weak clouding of the air with horizontal visibility from 1 to 10 km is called a veil. The veil can be strong (visibility 1-2 km), moderate (up to 4 km) and weak (up to 10 km). Fogs are distinguished by origin: advective and radiation. The deterioration in visibility complicates the work of transport - flights are interrupted, the schedule and speed of ground transport change. Drops of fog, settling on the surface or ground objects under the influence of gravity or air flow, moisten them. There have been repeated cases of overlapping of insulators of high-voltage power lines as a result of deposition of fog and dew drops on them. Fog drops, like dew drops, are a source of additional moisture for field plants. Settling on them, the drops maintain a high relative humidity around them. On the other hand, drops of fog, settling on plants, contribute to the development of decay.

At night, fogs protect vegetation from excessive cooling as a result of radiation, weaken the harmful effects of frost. During the day, fogs protect the vegetation from solar overheating. Settling of mist drops on the surface of machine parts leads to damage to their coatings and corrosion.

According to the number of days with fog, Russia can be divided into three parts: mountainous areas, the central elevated part and low-lying areas. The frequency of fog increases from south to north. Some increase in the number of days with fog is observed in spring. Fogs of all types can be observed both at negative and at positive temperatures of the soil surface (from 0 to 5°C).

Black ice is an atmospheric phenomenon that is formed as a result of freezing of drops of supercooled rain or fog on the surface of the earth and objects. It is a layer of dense ice, transparent or opaque, which grows on the windward side.

The most significant black ice is observed during the passage of southern cyclones. When cyclones move eastward from the Mediterranean Sea and fill them over the Black Sea, icy patches are observed in southern Russia.

The duration of sleet is different - from parts of an hour to 24 hours or more. Educated icing keeps on objects for a long time. As a rule, black ice forms at night at negative air temperatures (from 0° to - 3°С). Black ice, together with strong winds, causes significant damage to the economy: wires are torn under the weight of icing, telegraph poles fall, trees die, traffic stops, etc.

Hoarfrost is an atmospheric phenomenon, which is the deposition of ice on thin long objects (tree branches, wires). There are two types of frost - crystalline and granular. The conditions for their formation are different. Crystalline hoarfrost is formed during fog as a result of sublimation (the formation of ice crystals immediately from water vapor without its transition to a liquid state or upon rapid cooling below 0 ° C) of water vapor, consists of ice crystals. Their growth occurs on the windward side of objects in light winds and temperatures below -15°C. The length of the crystals, as a rule, does not exceed 1 cm, but can reach several centimeters. Granular hoarfrost - snow-like loose ice that grows on objects in foggy, mostly windy weather.

It has sufficient strength. The thickness of this frost can reach many centimeters. Most often, crystalline hoarfrost occurs in the central part of the anticyclone with high relative humidity below the inversion layer. Grainy hoarfrost, according to the conditions of formation, is close to sleet. Rime frost is observed throughout Russia, but is distributed unevenly, since its formation is influenced by local conditions - the height of the terrain, the shape of the relief, the exposure of the slopes, the protection from the prevailing moisture-bearing flow, etc.

Due to the low density of hoarfrost (bulk density from 0.01 to 0.4), the latter to a greater extent only causes increased vibration and sagging of power transmission and communication wires, but can also cause them to break. Hoarfrost poses the greatest danger to communication lines during strong winds, as the wind creates an additional load on the wires, which sag under the weight of deposits, and the risk of their breakage increases.

A snowstorm is an atmospheric phenomenon, which is the transfer of snow by the wind over the surface of the earth with a deterioration in visibility. There are such blizzards as a blowing snow, when most of the snowflakes rise a few centimeters above the snow cover; blowing blizzard if snowflakes rise to 2 m or more. These two types of blizzards occur without snow falling from the clouds. And, in the end, a general, or upper, blizzard - snowfall with a strong wind. Blizzards reduce visibility on the roads, interfere with the operation of transport.

A thunderstorm is a complex atmospheric phenomenon in which electrical discharges (lightning) occur in large rain clouds and between clouds and the ground, which are accompanied by a sound phenomenon - thunder, winds and heavy rainfall, often hail. Lightning strikes damage ground objects, power lines and communications. Squalls and downpours, floods and hail accompanying a thunderstorm cause damage to agriculture and some areas of industry. There are intramass thunderstorms and thunderstorms that occur in the zones of atmospheric fronts. Intra-mass thunderstorms, as a rule, are short-term and occupy a smaller area than frontal ones. They arise as a result of strong heating of the underlying surface. Thunderstorms in the atmospheric front zone are distinguished by the fact that they often occur in the form of chains of thunderstorm cells that move parallel to each other, covering a large area.

They occur on cold fronts, fronts of occlusion, as well as on warm fronts in warm, humid, usually tropical air. The zone of frontal thunderstorms has a width of tens of kilometers with a front length of hundreds of kilometers. Approximately 74% of thunderstorms are observed in the front zone, other thunderstorms are intramass.

During a thunderstorm:

in the forest to hide among low trees with dense crowns;

in the mountains and in open areas to hide in a pit, ditch or ravine;

fold all large metal objects 15-20 meters away from you;

having sheltered from a thunderstorm, sit down, bending your legs under you and lowering your head on your legs bent at the knees, connect your feet together;

put under yourself, a plastic bag, branches or spruce branches, stones, clothes, etc. isolating from the soil;

on the way, the group disperse, go one at a time, slowly;

in shelter, change into dry clothes, in extreme cases, carefully squeeze out wet ones.

During a thunderstorm, do not:

take cover near lone trees or trees protruding above others;

lean or touch rocks and sheer walls;

stop at the edges of the forest, large clearings;

walk or stop near bodies of water and in places where water flows;

hide under rocky canopies;

run, fuss, move in a tight group;

be in wet clothes and shoes;

stay on high ground;

be near watercourses, in crevices and cracks.

blizzard

A snow storm is one of the varieties of a hurricane, characterized by significant wind speeds, which contributes to the movement of huge masses of snow through the air, and has a relatively narrow band of action (up to several tens of kilometers). During a storm, visibility deteriorates sharply, and transport communication, both intracity and intercity, may be interrupted. The duration of the storm varies from several hours to several days.

Blizzard, blizzard, blizzard are accompanied by sharp temperature changes and snowfall with strong gusts of wind. The temperature difference, snowfall with rain at low temperatures and strong winds, creates conditions for icing. Power lines, communication lines, roofs of buildings, various supports and structures, roads and bridges are covered with ice or sleet, which often causes their destruction. Ice formations on the roads make it difficult, and sometimes completely hinder the operation of road transport. Pedestrian movement will be difficult.

Snowdrifts occur as a result of heavy snowfalls and snowstorms, which can last from several hours to several days. They cause disruption of transport communication, damage to communication lines and power lines, and negatively affect economic activity. Snow drifts are especially dangerous when snow avalanches come down from the mountains.

The main damaging factor of such natural disasters is the impact of low temperature on the human body, causing frostbite, and sometimes freezing.

In the event of an immediate threat, the population is alerted, the necessary forces and means, road and utility services are put on alert.

A snowstorm, blizzard or blizzard can last for several days, so it is recommended to create a supply of food, water, fuel in the house in advance, and prepare emergency lighting. You can leave the premises only in exceptional cases and not alone. Restrict movement, especially in rural areas.

Vehicles should only be used on main roads. In the event of a sharp increase in wind, it is advisable to wait out the bad weather in the village or near it. If the machine breaks down, do not leave it out of sight. If it is impossible to move further, mark the parking lot, stop (with the engine to the windward side), cover the engine from the side of the radiator. In case of heavy snowfall, make sure that the car is not covered with snow, i.e. shovel snow as needed. The car engine must be periodically warmed up to avoid its “defrosting”, while preventing exhaust gases from entering the cab (body, interior), for this purpose, make sure that the exhaust pipe is not blocked with snow. If there are several cars, it is best to use one car as a shelter, the engines of other cars must be drained of water.

In no case should you leave the shelter (car), in heavy snow, landmarks after a few tens of meters can be lost.

A snowstorm, snowstorm or blizzard can be waited out in a shelter equipped with snow. Shelter is recommended to be built only in open areas, where snow drifts are excluded. Before you take cover, you need to find landmarks on the ground in the direction of the nearest housing and remember their location.

Periodically, it is necessary to control the thickness of the snow cover by piercing the ceiling of the shelter, and to clear the entrance and the ventilation hole.

It is possible to find an elevated, steadily standing object in an open and snowless area, take cover behind it and constantly discard and trample down the arriving snow mass with your feet.

In critical situations, it is permissible to completely bury yourself in dry snow, for which you put on all warm clothes, sit with your back to the wind, cover yourself with plastic wrap or a sleeping bag, pick up a long stick and let the snow sweep you. Constantly clear the ventilation hole with a stick and expand the volume of the formed snow capsule in order to be able to get out of the snow drift. Inside the resulting shelter, a landmark arrow should be laid out.

Remember that a blizzard due to multi-meter snow drifts and snowdrifts can significantly change the appearance of the area.

The main types of work during snow drifts, snowstorms, snowstorms or blizzards are:

search for missing people and providing them with first aid, if necessary;

clearing roads and areas around buildings;

providing technical assistance to stuck drivers;

elimination of accidents on utility and energy networks.

Hail is an atmospheric phenomenon associated with the passage of cold fronts. Occurs with strong ascending air currents during the warm seasons. Droplets of water, falling to a great height with air currents, freeze, and ice crystals begin to grow on them in layers. Drops become heavier and begin to fall down. When falling, they increase in size from merging with drops of supercooled water. Sometimes hail can reach the size of a chicken egg. As a rule, hail falls from large rain clouds during a thunderstorm or a downpour. It can cover the ground with a layer of up to 20-30 cm. The number of days with hail increases in mountainous areas, on hills, in areas with rugged terrain. Hail falls mainly in the second half of the day in relatively small areas of several kilometers. Hail usually lasts from several minutes to a quarter of an hour. The hail causes significant material damage. It destroys crops, vineyards, knocks flowers and fruits from plants. If the size of the hailstones is significant, it can cause the destruction of buildings and death of people. At present, methods have been developed for determining hail clouds, and a hail control service has been created. Dangerous clouds are "shot" with special chemicals.

Dry wind - hot and dry wind with a speed of 3 m/s or more, with high air temperature up to 25°C and low relative humidity up to 30%. Dry winds are observed in partly cloudy weather. Most often they occur in the steppes along the periphery of anticyclones that form over the North Caucasus and Kazakhstan.

The highest dry wind speeds were observed during the day, the lowest - at night. Dry winds cause great damage to agriculture: they raise the water balance of plants, especially when there is a lack of moisture in the soil, since intensive evaporation cannot be compensated by the flow of moisture through the root system. With prolonged action of dry winds, the ground part of the plants turns yellow, the foliage curls, their wilting occurs and even the death of field crops.

Dust, or black, storms are the transfer of large amounts of dust or sand by strong winds. They occur during dry weather due to the winding of sprayed soil over great distances. The occurrence, frequency, and intensity of dust storms are greatly influenced by orography, the nature of soils, forest cover, and other terrain features.

Most often, dust storms occur from March to September. The most intense and dangerous spring dust storms are during a prolonged absence of rain, when the soil dries out, and the plants are still underdeveloped and do not form a continuous cover. At this time, storms blow out the soil over vast areas. Reduced horizontal visibility. S.G. Popruzhenko investigated a dust storm in 1892 in the south of Ukraine. Here is how he described it: “A dry, strong east wind tore the ground for several days and drove masses of sand and dust. The crops, which turned yellow from dry air, were cut under the root, like a sickle, but the roots could not survive. The earth was demolished up to 17 cm deep.Canals filled up to 1.5 m.

Hurricane

A hurricane is a wind of destructive force and considerable duration. A hurricane occurs suddenly in areas with a sharp drop in atmospheric pressure. The speed of a hurricane reaches 30 m/s or more. In terms of its harmful effects, a hurricane can be compared with an earthquake. This is explained by the fact that hurricanes carry colossal energy, its amount released by a hurricane of average power in one hour can be compared with the energy of a nuclear explosion.

A hurricane can capture an area up to several hundred kilometers in diameter and is capable of moving thousands of kilometers. At the same time, the 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 . There were times when hurricane winds threw trains off the rails and knocked down factory chimneys. Often hurricanes are accompanied by heavy rains that cause flooding.

A storm is a type of hurricane. The wind speed during a storm is not much less than the speed of a hurricane (up to 25-30 m/s). Losses and destruction from storms are significantly less than from hurricanes. Sometimes a strong storm is called a storm.

A tornado is a strong small-scale atmospheric vortex with a diameter of up to 1000 m, in which the air rotates at a speed of up to 100 m / s, which has great destructive power (in the USA it is called a tornado).

On the territory of Russia, tornadoes are observed in the Central region, the Volga region, the Urals, Siberia, Transbaikalia, and the Caucasian coast.

A tornado is an ascending vortex consisting of extremely rapidly rotating air mixed with particles and moisture, sand, dust and other suspensions. On the ground, he moves in the form of a dark column of spinning air with a diameter of several tens to several hundred meters.

In the internal cavity of the tornado, the pressure is always reduced, so any objects that are in its path are sucked into it. The average speed of the tornado is 50-60 km / h, when it approaches, a deafening rumble is heard.

Strong tornadoes travel tens of kilometers and tear off roofs, uproot trees, lift cars into the air, scatter telegraph poles, and destroy houses. Threat notification is carried out by giving a signal "Attention to all" by a siren and subsequent voice information.

Actions upon receipt of information about an impending hurricane, storm or tornado - you should carefully listen to the instructions of the civil defense authority, which will report the estimated time, strength of the hurricane and recommendations on the rules of conduct.

Upon receipt of a storm warning, it is necessary to immediately begin to carry out preventive work:

reinforce insufficiently strong structures, close doors, dormer openings and attic spaces, sheathe windows with boards or close them with shields, and glue the glass with strips of paper or cloth, or, if possible, remove it;

in order to balance the external and internal pressure in the building, it is advisable to open the doors and windows on the leeward side and fix them in this position;

from roofs, balconies, loggias and window sills it is necessary to remove things that, if they fall, can cause injury to people. Items located in the yards must be secured or brought into the premises;

it is also advisable to take care of emergency lamps - electric lamps, kerosene lamps, candles. It is also recommended to create stocks of water, food and medicines, especially dressings;

put out the fire in the stoves, check the condition of electrical switches, gas and water taps;

take pre-prepared places in buildings and shelters (in case of tornadoes - only in basements and underground structures). Indoors, you need to choose the safest place - in the middle part of the house, in the corridors, on the ground floor. To protect against injury from glass fragments, it is recommended to use built-in wardrobes, durable furniture and mattresses.

The safest places during a storm, hurricane or tornado are shelters, basements and cellars.

If a hurricane or tornado caught you in an open area, it is best to find any natural depression in the ground (ditch, pit, ravine or any recess), lie down on the bottom of the depression and press firmly against the ground. Leave the transport (regardless of whichever one you are in) and take cover in the nearest basement, shelter or recess. Take measures to protect against heavy rainfall and large hail, as hurricanes are often accompanied by them.

be on bridges, as well as in close proximity to objects that use poisonous, potent and flammable substances in their production;

take cover under separate trees, poles, come close to power line supports;

be near buildings from which gusts of wind blow away tiles, slates and other objects;

After receiving a message about the stabilization of the situation, you should leave the house carefully, you need to look around for hanging objects and parts of structures, broken electrical wires. it is possible that they are under voltage.

Without extreme necessity, do not enter damaged buildings, but if such a need arose, then this should be done carefully, making sure that there are no significant damage to stairs, ceilings and walls, fires, breaks in electrical wires, and elevators should not be used.

The fire should not be lit until there is confidence that there was no gas leak. When outdoors, stay away from buildings, poles, high fences, etc.

The main thing in these conditions is not to panic, to act competently, confidently and reasonably, to prevent oneself and keep others from unreasonable acts, to provide assistance to the victims.

The main types of damage to people during hurricanes, storms and tornadoes are closed injuries of various areas of the body, bruises, fractures, concussions, wounds accompanied by bleeding.

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, 7 huge slabs and dozens of smaller slabs are distinguished. The upper part of most plates is both the continental and oceanic crust, that is, on these plates there are continents, seas and oceans.

The plates rest on a relatively soft, plastic layer of the upper mantle, over which they slowly move at a rate of 1 to 6 cm per year. Neighboring plates approach, diverge or slide one relative to the 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 in the depths of the Earth and on its surface, complex processes constantly occur. So, for example, when plates collide with the oceanic earth's crust, deep-sea depressions (troughs) can occur, and when plates, which are the base of the continental earth's crust, collide, mountains can form. When there is a convergence of two plates with the continental crust, their edges, together with all the sedimentary rocks accumulated on them, are crushed into folds, forming mountain ranges. With the onset of critical overloads, the folds are displaced and torn. Breaks occur instantly, accompanied by a push or a series of pushes that have the character of blows. The energy released during the rupture is transmitted in the thickness of the earth's crust in the form of elastic seismic waves and leads to earthquakes.

The boundary regions between the lithospheric plates are called seismic belts. These are the most restless, mobile areas of the planet. Most 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 the activity of geological processes that occur in the 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.

Hazardous 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 facilities and the natural environment.

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

Air in the troposphere moves in both 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 falls down. There is a downward movement of air. For this reason, near the Earth's surface near the poles, the pressure 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 is constantly moving from an area of ​​high pressure to an area of ​​low 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 about 30° north and south latitudes, forming areas of high pressure in both hemispheres.

Large volumes of air in the troposphere with uniform properties are called air masses. Depending on the place of formation of air masses, four types of them 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, air masses 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 those places where these air masses come. The interaction of various air masses leads to the formation of moving atmospheric vortices in the troposphere - cyclones and anticyclones.

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

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

With the movement of air masses, with their interaction, the emergence of dangerous meteorological phenomena that can cause natural disasters is associated. These are typhoons and hurricanes, storms, snowstorms, tornadoes, thunderstorms, droughts, 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 the waters on Earth that are not part of the rocks are 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 1 billion tons. The Earth contains 1.5 billion km 3 of water, 97% of which is the World Ocean. At present, it is customary to divide the World Ocean into 4 separate oceans and 75 seas with bays and straits.

Water is in constant circulation, while closely interacting with the air shell of the Earth and with 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. Part of the water immediately returns with rain back to the ocean, part is carried by winds to land, where it falls to the surface in the form of rain or snow. Getting 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 ground waters carry water to the World Ocean, replenishing its loss. Water, evaporating from the surface of the World Ocean, again finds itself in the atmosphere, and the cycle closes.

Such a movement of water between the constituent parts of nature and all parts of the earth's surface occurs constantly and continuously 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 passes from one link to another, linking 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 that have a damaging effect on people, farm animals and plants, economic objects and the natural environment.

Natural hazards of a hydrological nature include floods, tsunamis and mudflows.

Biological natural hazards

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

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

• natural fires (forest fires, fires of steppe and grain massifs, peat fires and underground fires of fossil fuels);
• infectious diseases of people (isolated 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 animal diseases (single outbreaks of exotic and especially dangerous infectious diseases, enzootics, epizootics, panzootics, infectious diseases of farm animals of unknown etiology);
• defeat of agricultural plants by diseases and pests (epiphytoty, panphytoty, disease of agricultural plants of unknown etiology, mass distribution of plant pests).

natural fires include forest fires, fires of steppe and grain massifs, peat fires. The most common forest fires that occur annually, bring enormous losses and lead to human casualties.

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

In hot weather, in the absence of rain for 15-20 days, the forest becomes a fire hazard. Statistics show that in 90-97% of cases, the cause of forest fires is the vital activity of people.

Epidemic- the widespread spread of an infectious disease among people, significantly exceeding the incidence rate usually recorded in a given territory. The usual (minimal) incidence for a given area is most often isolated cases of diseases that do not have a connection with each other.

epizootics- mass infectious diseases of animals.

Epiphytoties- mass diseases of plants.

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

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

Space hazardous natural phenomena

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 go out in the night sky. it meteors- small celestial bodies. We observe a short-term flash of hot luminous 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 the time of movement in the atmosphere the solid particles of the meteor do not have time to completely collapse and burn out, then their remnants fall to the Earth. it meteorites.

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

Comets- these are the bodies of the solar system moving rapidly in the starry sky, moving in highly elongated orbits. As they approach the Sun, they begin to glow and they have a “head” and “tail”. The central part of the "head" is called the nucleus. The core diameter 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 that have escaped 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 space bodies are known that can cross the Earth's orbit. In total, according to astronomers' forecasts, there are approximately 300 thousand asteroids and comets in space.

The 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 of the natural environment around us is constantly changing, there are processes of metabolism and energy, and all this, taken together, gives rise to various natural phenomena. Depending on the intensity of the manifestation and the power of the ongoing processes, these natural phenomena can pose a threat to human life and the situation of a natural emergency.

Test yourself

1. Name the main groups of hazardous natural phenomena.
2. List the main natural phenomena of a geological nature and explain the reasons for their occurrence.
3. What are the main natural phenomena of a meteorological and hydrological nature? Specify their interdependence.
4. Describe natural hazards of a biological nature. Name the reasons for their occurrence.

After lessons

Learn from adults, look on the Internet and record in a safety diary the main natural phenomena of geological, meteorological, hydrological and biological origin in your area.

Storms and hurricanes

The uneven heating of the atmosphere leads to a change in atmospheric pressure and, as a result, causes a general circulation of air in the atmosphere, which determines the climate, weather, and the possibility and frequency of meteorological emergencies.

The area of ​​low atmospheric pressure with a minimum in the center is called a cyclone. A cyclone in diameter reaches several thousand kilometers. Cyclones form cloudy weather with strong winds.

Storms and hurricanes occur during cyclones. The wind speed near the earth's surface exceeds 20 m/s and can reach 100 m/s.

The danger of these natural phenomena is created as a result of dynamic load from the flow of air masses. The destruction of buildings, structures and other objects, the defeat of people occurs as a result of the action of high-speed air pressure, which causes significant pressure on objects.

To characterize the strength of the wind, the 12-point Beaufort scale is often used, which is based on the characteristic consequences of the action of the wind on the earth's surface (Table 2.2).

Table 2.2 - Beaufort scale

Points	Wind speed m/s	Wind characteristic	Effects of the wind
	0-0,5	calm	the leaves on the trees do not move, the smoke from the chimneys rises vertically
	0,5-1,7	quiet	the smoke deviates a little, the wind is almost not felt
	1,7-3,3	light	feel the slight breeze
	3,3-5,2	weak	swaying small branches
	5,2-7,4	moderate	dust rises, branches of medium thickness sway
	7,4-9,8	big enough	thin trees and thick branches sway, ripples form on the water
	9,8-12	strong	swaying thick tree trunks
	12,0-15,0	very strong	big trees sway, it's hard to go against the wind
	15,0-18,0	extremely strong	thick tree trunks break
	18,0-22,0	storm	destroyed light buildings, fences
	22,0-25,0	heavy storm	rather strong buildings are destroyed, the wind uproots trees
	25,0-29,0	fierce storm	significant damage, overturned wagons, cars
	over 29	Hurricane	destroyed brick houses, stone fences

Storms divided into vortex, dust and stream (storm at sea) - wind force of 9-11 points, wind speed of 20-32 m / s causes damage to buildings, uproots trees, overturns cars, destroys overhead communication lines and power lines. The defeat of people occurs as a result of damage to buildings, overturning machines and mechanisms, falling trees.

Hurricane - wind force 12 points, wind speed 32-60 m / s, sometimes up to 100 m / s - destroys and devastates everything in its path.

For security during a storm and a hurricane, a "Storm Warning" is issued. According to this report, the access to the sea of ​​floating craft is limited, tower cranes and other large-sized construction mechanisms are secured by a "storm", the movement of vehicles is limited, logging, field work, etc. are stopped. In addition, preventive measures at enterprises provide for the strengthening of structures, buildings, cleaning or securing objects that can injure people, take measures to preserve equipment.

Doors and windows are tightly closed in private houses, apartments and industrial premises. Objects are taken from roofs, loggias, balconies, which, due to gusts of wind, can fall down and injure people. Items located in the yards are fixed or brought into the room.

A storm (hurricane) may be accompanied by a thunderstorm. At the same time, it is necessary to avoid situations in which the possibility of lightning strikes increases.

Forecasting and warning about a storm (hurricane) is carried out by the hydrometeorological service using modern instruments, including meteorological satellites, which record the occurrence of extreme meteorological phenomena, after which the possible direction of their movement, probable power and time of approach to a certain area are calculated. The administrative bodies of regions, districts, civil protection headquarters, agricultural, forestry and industrial facilities are notified of the approach of a hurricane (storm). Local authorities notify the population, and the heads of enterprises and the headquarters of the PP - employees. This makes it possible to alert the formations of civil protection in time, to carry out preventive work in areas of possible action of a hurricane or storm, and to effectively eliminate the consequences of a natural disaster.

In the area of ​​a hurricane, storm, tornado, civil protection formations and the population must be prepared for:

Carrying out the evacuation of the population and material assets from dangerous areas;

Rescuing people; search and release of victims from under destroyed buildings and structures;

The provision of first aid and the delivery of victims to medical institutions;

extinguishing fires;

Elimination of accidents at production facilities and utility networks.

hail

Hail - atmospheric precipitation in the form of ice particles of irregular shape. Intense hail destroys agricultural crops, and especially large hail leads to the destruction of roofs, damages cars, can cause serious injury or even death.

Smog

Chemical reactions that occur in the air lead to the formation of smoky fogs. Smog occurs under the following conditions: firstly, atmospheric pollution as a result of intense intake of dust, smoke, exhaust and industrial gases, and other products in the form of fine particles that cities emit into the air, and secondly, the long existence of anticyclones, in which pollutants accumulate in the surface layer of the atmosphere. Great smoke, which in its effect is similar to smog, also occurs during large forest fires. Smog and smoke cause exacerbation of chronic lung diseases in people, deterioration of well-being, cause certain material damage associated with the removal of plaque on equipment located on the street, windows, and the like.

There are three layers of smog:

Lower, located in the surface layers of air. It is formed mainly from the exhaust gases of transport and the redistribution of dust raised into the air;

The second layer is formed due to emissions from heating systems and is located at a height of about 20-30 m above the ground;

The third layer is located at a height of 50-100 m or more and is formed mainly as a result of emissions from industrial enterprises. Smog is quite toxic.

Lightning

Lightning and discharges are to some extent associated with matter in the plasma state. Lightning is linear and ball.

Linear lightning occurs when the electric field strength between the clouds and the ground increases. Linear lightning parameters:

Length - no more than 10 km;

Channel diameter - up to 40 cm;

Current strength - 105-106 A;

Time of one lightning discharge - 10 -4 s;

The temperature in the lightning channel is up to 10,000°K.

A lightning strike, as a result of its thermal and electrodynamic action, can cause injury and death of people, destruction of structures, fire. The greatest damage occurs from lightning strikes to ground objects in the absence of a lightning rod or other good conductors between the strike site and the ground. When a lightning strikes, from an electrical breakdown in the material, channels appear in which a high temperature is formed and part of the material evaporates, followed by an explosion and fire. In addition to the direct action of lightning, during a strike, a significant difference in electrical potentials between individual objects may occur, which can lead to electric shock to people.

Protection against lightning is carried out with the help of lightning rods, which are equipped with all houses and buildings. The degree of protection depends on the purpose of the house or structure, the intensity of thunderstorm activity in the area and the expected reliability of the object being struck by lightning.

Ball lightning is generated when powerful linear lightning strikes, they have a diameter of about 30 cm, their light emission is approximately equal to 100 W of a light bulb, the luminous flux is ~ 1400 lumens, the thermal radiation is small, the speed of movement is 3-5 m/s, sometimes up to 10 m/s, the energy released during the explosion is about 10,000 J. Ball lightning is often attracted to metal objects, its decay occurs in most cases by an explosion, but it can also simply fade and fall apart. The explosion of ball lightning is not powerful, but it can cause burns, objects torn off by the explosion are dangerous. The result of the action of ball lightning can be a fire.

Personal safety during an encounter with ball lightning, you need to sit or stand still, watching it. If the lightning approaches, you can blow on it - the lightning will fly away. In any case, it is necessary to move as far as possible from ball lightning, since the "behavior" of lightning is unpredictable.