What is the most important natural phenomenon. General characteristics of natural emergencies
Nature is not always as serene and beautiful as in the photograph above these lines. Sometimes she shows us her dangerous manifestations. From violent volcanic eruptions to terrifying hurricanes, nature's fury is best viewed from afar and from the sidelines. We often underestimate the amazing and destructive power of nature, and it reminds us of this from time to time. While it all looks exciting in photographs, the consequences of such events can be very scary. We must respect the power of the planet we live on. We have made this photo and video collection of frightening natural phenomena for you.
TORNADOES AND OTHER TYPES OF TOrnadoes
All these types of atmospheric phenomena are dangerous vortex manifestations of the elements.
Tornado or tornado arises in a thundercloud and spreads down, often to the very surface of the earth, in the form of a cloud arm or trunk with a diameter of tens and hundreds of meters. Tornadoes can appear in many shapes and sizes. Most tornadoes appear as a narrow funnel (only a few hundred meters across), with a small cloud of debris near the earth's surface. A tornado can be completely hidden by a wall of rain or dust. These tornadoes are especially dangerous because even experienced meteorologists may not recognize them.
Tornado with lightning:
Tornado in Oklahoma, USA (May site 2010):
Supercell thunderstorm in Montana, USA, formed by a huge rotating thundercloud 10-15 km high and d about 50 km in diameter. Such a thunderstorm creates tornadoes, gusty winds, and large hail:
Thunderclouds:
View of a hurricane tornado from space:
There are other vortex phenomena that are similar in appearance, but different in nature:
Formed as a result of the rise of warmer air from the surface of the earth. Tornado-vortices, unlike tornadoes, develop from the bottom up, and the cloud above them, if formed, is a consequence of the vortex, and not its cause.
Dust (sand) whirlwind- This vortex movement air that appears at the surface of the earth during the day when there is little cloud and usually hot weather with strong heating of the earth's surface sun rays. The whirlwind lifts dust, sand, pebbles, and small objects from the surface of the earth and sometimes transports them to a site over a considerable distance (hundreds of meters). The vortices pass in a narrow strip, so that in a weak wind its speed inside the vortex reaches 8-10 m/s or more.
Sandspout:
Or a firestorm forms when a column of hot, rising air interacts with or causes a fire on the ground. It is a vertical whirlpool of fire in the air. The air above it heats up, its density decreases, and it rises. From below, cold masses of air from the periphery enter in its place, which immediately heat up. Steady flows are formed, spiraling from the ground to a height of up to 5 km. A chimney effect occurs. The pressure of hot air reaches hurricane speeds. The temperature rises to 1000˚C. Everything burns or melts. At the same time, everything that is nearby is “sucked” into the fire. And so on until everything that can burn has burned.
A site is a funnel-shaped air-water vortex, similar in nature to an ordinary tornado, formed above the surface of a large body of water and connected to cumulus cloud. A waterspout can form when a regular tornado passes over a water surface. Unlike a classic tornado, a waterspout lasts only 15-30 minutes, is much smaller in diameter, the speed of movement and rotation is two to three times lower, and is not always accompanied by hurricane winds.
DUST OR SAND STORMS
Sand (dust) storm is a dangerous atmospheric phenomenon that manifests itself in the form of wind transfer of large quantities of soil particles, dust or small grains of sand from the surface of the Earth. The height of the layer of such dust can be several meters, and horizontal visibility is noticeably deteriorated. For example, at a level of 2 meters visibility is 1-8 kilometers, but often visibility in a storm is reduced to several hundred or even tens of meters. Dust storms The site occurs mainly when the soil surface is dry and the wind speed is more than 10 meters per second.
The fact that a storm is approaching can be understood in advance by the incredible silence that forms around you, as if you had suddenly found yourself in a vacuum. This silence is depressing, creating an inexplicable anxiety inside you.
Sandstorm on the streets of Onslow in northwestern Australia, January 2013:
Sandstorm in Golmud village, Qinghai province, China, 2010:
Red sandstorm in Australia:
TSUNAMI
is a dangerous natural disaster that represents sea waves, resulting from the shift seabed during underwater and coastal earthquakes. Once formed in any place, a tsunami can spread from high speed(up to 1000 km/h) for several thousand kilometers, with the tsunami height initially ranging from 0.1 to 5 meters. When reaching shallow water, the wave height increases sharply, reaching a height of 10 to 50 meters. Huge masses of water washed ashore lead to flooding and destruction of the area, as well as the death of people and animals. In front of the water shaft, air spreads shock wave. It acts similarly to a blast wave, destroying buildings and structures. The tsunami wave may not be the only one. Very often this is a series of waves that roll onto the shore at intervals of 1 hour or more.
Tsunami in Thailand caused by earthquake (9.3 points) in Indian Ocean December 26, 2004:
CATASTROPHIC FLOODS
Flood— flooding of the territory with water, which is a natural disaster. Floods happen different types and are caused by various reasons. Catastrophic floods lead to loss of life, irreparable environmental damage, and cause material damage, covering vast territories within one or more water systems. At the same time, economic activity and production activities are completely paralyzed, and the lifestyle of the population is temporarily changed. The evacuation of hundreds of thousands of people, an inevitable humanitarian catastrophe requires the participation of the entire world community, the problem of one country becomes a problem of the whole world.
Flood in Khabarovsk and Khabarovsk Territory, caused by intense downpours that covered the entire Amur River basin and lasted about two months (2013):
Flooding in New Orleans after a hurricane. New Orleans (USA) stands on damp soil that the city cannot support. Orleans is slowly sinking into the ground, and the Gulf of Mexico is gradually rising around it. Most of New Orleans is already 1.5 to 3 meters below sea level. This in to a large extent contributed to Hurricane Katrina in 2005:
Flood in Germany, in the Rhine River basin (2013):
Flood in Iowa, USA (2008):
THUNDERLIGHTNING
Lightning discharges (lightning) represent a giant electric spark discharge into the site atmosphere, with very long length sparks, usually occurring during a thunderstorm, manifested by a bright flash of light and accompanying thunder. The total length of the lightning channel reaches several kilometers (on average 2.5 km), and a significant part of this channel is located inside a thundercloud. Some discharges extend up to 20 km in the atmosphere. The current in a lightning discharge reaches 10-20 thousand amperes, so not all people survive a lightning strike.
forest fire- This is the spontaneous, uncontrolled spread of fire across forest areas. The causes of fires in the forest can be natural (lightning, drought, etc.) or artificial, when the cause is people. There are several types of forest fires.
Underground (soil) fires in the forest are most often associated with peat fire, which becomes possible as a result of drainage of swamps. They can be barely noticeable and spread to a depth of several meters, as a result of which they pose an additional danger and are extremely difficult to extinguish. Like, for example, the peat fire in the Moscow region (2011):
At ground fire forest litter, lichens, mosses, grasses, branches that have fallen to the ground, etc. burn.
Horse forest fire covers leaves, needles, branches and the entire crown, can cover (in the event of a general fire) the grass-moss cover of the soil and undergrowth. They usually develop in dry conditions. windy weather from a ground fire, in plantations with low crowns, in plantations of different ages, as well as in cases of abundant coniferous undergrowth. This is usually the final stage of a fire.
VOLCANOES
Volcanoes are geological formations on the surface of the earth's crust, most often in the form of a mountain, where magma comes to the surface, forming lava, volcanic gases, rocks and pyroclastic flows. When through the cracks in earth's crust Molten magma pours out, a volcano erupts, the site is named after the Roman god of fire and blacksmithing.
Karymsky Volcano is one of the most active volcanoes Kamchatka:
Underwater volcano – the coast of the Tonga archipelago (2009):
Underwater volcano and subsequent tsunami:
Volcanic eruption photographed from space:
Klyuchevskoy Volcano in Kamchatka (1994):
The eruption of Mount Sinabung in Sumatra was accompanied by several mini-tornadoes:
Puyehue volcano eruption in Chile:
Lightning in the ash cloud of the Chaiten volcano in Chile:
Volcanic lightning:
EARTHQUAKES
Earthquake– these are tremors and vibrations of the Earth’s surface caused by natural tectonic processes (movement of the earth’s crust and the displacements and ruptures occurring in it) or artificial processes (explosions, filling of reservoirs, collapse of underground cavities in mine workings). May result in volcanic eruptions and tsunamis.
Japan earthquake followed by tsunami (2011):
LANDSLIDE
Landslide- a separated mass of loose rocks, slowly and gradually or abruptly sliding along the inclined plane of separation, while often maintaining its coherence, solidity and without overturning its soil.
VILLAGE
Sel- flow with a very high concentration of mineral particles, stones and debris rocks(something between a liquid and a solid mass), suddenly appearing in small pools mountain rivers and is usually caused by heavy rainfall or rapid snow melting.
SNOW AVALANCHES
Snow avalanches belong to landslides. This is a mass of snow falling or sliding down the slopes of mountains.
This is one of record avalanches measuring 600 thousand cubic meters. Film crew not injured:
“This is the consequence of an avalanche - snow dust, it flew up high, and everything disappeared as if in a fog. Everyone was doused with snow dust, which, by inertia, continued to move at the speed of a snowstorm. It became dark as night. Because of fine-fine snow the site was difficult to breathe. My arms and legs instantly went numb. I didn't see anyone around. Although there were people nearby,” said Anton Voitsekhovsky, a member of the film crew.
Report natural phenomena Grade 7 will briefly tell you what natural phenomena are and what their consequences may be.
Natural Hazard Report
Natural phenomena accompany us wherever we go. Rain, snow, scorching sun, storm, storm are an integral part of nature. A report on natural phenomena will help you understand their types in more detail and understand what's what.
According to the place of occurrence, natural phenomena are divided into the following groups:
- Geological
Hazardous natural phenomena report include earthquakes, volcanoes, landslides, landslides and avalanches.
- Earthquake is a natural phenomenon that is associated with geological processes occurring in the Earth's lithosphere. It manifests itself in the form of vibrations of the earth's surface and tremors that occur after sudden ruptures and displacements in the upper part of the mantle or the earth's crust.
- Volcano It is a conical mountain from which a hot substance, magma, periodically emerges to the surface.
- Landslide This is a sliding downward displacement of soil masses under the influence of gravity. Occurs on slopes when the stability of rocks or soil is disrupted. May occur naturally after an earthquake or heavy rainfall and artificially after human activity (soil excavation, deforestation).
- Collapses this is the separation and fall of rocks from large mass, their overturning and rolling down on slopes. During the rolling process, they can be crushed into smaller parts. The causes of collapses are: water activity, geological processes and cracks or layering of the rocks that make up the mountain, eroding the underlying rocks.
- snow avalanche is a collapse of a large mass of snow on mountain slopes. The tilt angle is at least 15°. The causes of this natural phenomenon are intense snow melting, human activity, earthquakes, and prolonged snowfall.
- Meteorological
- Hydrological
- Biological
A brief report on dangerous natural phenomena is completed by forest fires, epidemics, epizootics and epiphytoties.
- forest fire. This is an uncontrolled burning vegetation cover, which spreads through the forest area at high speed. It can be upper (the surface of the earth burns) and lower, underground (peat in marshy and swampy soils ignites).
- Epidemic. Massive spread of an infectious disease among the population with a significant excess of the incidence rate recorded in a given area.
- Epizootic. This is the massive spread of an infectious disease among animals. For example, swine fever, chicken flu, foot and mouth disease, cattle brucellosis.
- Epiphytoty. Wide use infectious disease among plants. For example, wheat rust, powdery mildew, late blight.
We hope that "Natural Phenomena" short message helped you prepare for class. You can leave a brief message about natural phenomena using the comment form below.
Natural hazards mean extreme climatic or meteorological phenomena, occurring naturally at one point or another on the planet. In some regions, such hazardous phenomena may occur with greater frequency and destructive force than in others. Dangerous natural phenomena develop into natural disasters when the infrastructure created by civilization is destroyed and people themselves die.
1. Earthquakes
Among all natural hazardous phenomena First place should be given to earthquakes. In places where the earth's crust breaks, tremors occur, which cause vibrations of the earth's surface with the release of gigantic energy. The resulting seismic waves are transmitted over very long distances, although these waves have the greatest destructive power at the epicenter of the earthquake. Due to strong vibrations of the earth's surface, massive destruction of buildings occurs.
Since quite a lot of earthquakes occur, and the surface of the earth is quite densely built up, the total number of people throughout history who died as a result of earthquakes exceeds the number of all other victims natural disasters and numbers in many millions. For example, for last decade Around the world, about 700 thousand people died from earthquakes. Entire settlements instantly collapsed from the most destructive shocks. Japan is the country most affected by earthquakes, and one of the most catastrophic earthquakes occurred there in 2011. The epicenter of this earthquake was in the ocean near the island of Honshu; on the Richter scale, the force of the tremors reached 9.1. Powerful tremors and the subsequent destructive tsunami disabled the Fukushima nuclear power plant, destroying three out of four power units. Radiation covered a significant area around the station, making densely populated areas, so valuable in Japanese conditions, uninhabitable. The colossal tsunami wave turned into mush what the earthquake could not destroy. Only officially over 16 thousand people died, to which we can safely include another 2.5 thousand who are considered missing. In this century alone, destructive earthquakes occurred in the Indian Ocean, Iran, Chile, Haiti, Italy, and Nepal.
2. Tsunami waves
A specific water disaster in the form of tsunami waves often results in numerous casualties and catastrophic destruction. As a result of underwater earthquakes or shifts tectonic plates Very fast, but barely noticeable waves arise in the ocean, which grow into huge ones as they approach the shores and reach shallow water. Most often, tsunamis occur in areas with increased seismic activity. A huge mass of water, quickly approaching the shore, destroys everything in its path, picks it up and carries it deep into the coast, and then carries it into the ocean with a reverse current. People, unable to sense danger like animals, often do not notice the approach of a deadly wave, and when they do, it is too late.
Usually killed by a tsunami more people than from the earthquake that caused it (the latest case in Japan). In 1971, the most powerful tsunami ever observed occurred there, the wave of which rose 85 meters at a speed of about 700 km/h. But the most catastrophic was the tsunami observed in the Indian Ocean (source - an earthquake off the coast of Indonesia), which claimed the lives of about 300 thousand people along a large part of the Indian Ocean coast.
A tornado (in America this phenomenon is called a tornado) is a fairly stable atmospheric vortex, most often occurring in storm clouds. He's visual...
3. Volcanic eruption
Throughout its history, humanity has remembered many catastrophic volcanic eruptions. When the pressure of magma exceeds the strength of the earth's crust at the weakest points, which are volcanoes, it ends in an explosion and outpouring of lava. But the lava itself, from which you can simply walk away, is not so dangerous as the hot pyroclastic gases rushing from the mountain, penetrated here and there by lightning, as well as the noticeable influence of the strongest eruptions on the climate.
Volcanologists count about half a thousand dangerous active volcanoes, several dormant supervolcanoes, not counting thousands of extinct ones. Thus, during the eruption of Mount Tambora in Indonesia, the surrounding lands were plunged into darkness for two days, 92 thousand inhabitants died, and cold temperatures were felt even in Europe and America.
List of some major volcanic eruptions:
- Volcano Laki (Iceland, 1783). As a result of that eruption, a third of the island's population died - 20 thousand inhabitants. The eruption lasted for 8 months, during which streams of lava and liquid mud erupted from volcanic fissures. Geysers have become more active than ever. Living on the island at this time was almost impossible. The crops were destroyed and even the fish disappeared, leaving the survivors hungry and suffering from unbearable living conditions. This may be the longest eruption in human history.
- Volcano Tambora (Indonesia, Sumbawa Island, 1815). When the volcano exploded, the sound of the explosion spread over 2 thousand kilometers. Even the remote islands of the archipelago were covered with ash, and 70 thousand people died from the eruption. But even today Tambora is one of the highest mountains in Indonesia, which remain volcanically active.
- Volcano Krakatoa (Indonesia, 1883). 100 years after Tambora, another catastrophic eruption occurred in Indonesia, this time “blowing the roof off” (in literally) Krakatoa volcano. After the catastrophic explosion that destroyed the volcano itself, frightening rumbles were heard for another two months. A gigantic amount of rock, ash and hot gases were thrown into the atmosphere. The eruption was followed by a powerful tsunami with wave heights of up to 40 meters. These two natural disasters together destroyed 34 thousand islanders along with the island itself.
- Volcano Santa Maria (Guatemala, 1902). After a 500-year hibernation, this volcano woke up again in 1902, beginning the 20th century with the most catastrophic eruption, which resulted in the formation of a one and a half kilometer crater. In 1922, Santa Maria reminded itself again - this time the eruption itself was not too strong, but the cloud of hot gases and ash brought the death of 5 thousand people.
4. Tornadoes
Ecological disasters have their own specifics - during them not a single person may die, but very significant damage will be caused...
A tornado is a very impressive natural phenomenon, especially in the United States, where it is called a tornado. This air flow, twisted in a spiral into a funnel. Small tornadoes resemble slender, narrow pillars, and giant tornadoes can resemble a mighty carousel reaching towards the sky. The closer you are to the funnel, the stronger the wind speed is; it begins to drag along increasingly larger objects, up to cars, carriages and light buildings. In the “tornado alley” of the United States, entire city blocks are often destroyed and people die. The most powerful vortices of the F5 category reach a speed of about 500 km/h at the center. The state that suffers the most from tornadoes every year is Alabama.
There is a variety fire tornado, which sometimes occurs in areas of massive fires. There, from the heat of the flame, powerful upward currents are formed, which begin to twist into a spiral, like an ordinary tornado, only this one is filled with flame. As a result, a powerful draft is formed near the surface of the earth, from which the flame grows even stronger and incinerates everything around. When a catastrophic earthquake occurred in Tokyo in 1923, it caused massive fires that led to the formation of a fire tornado that rose 60 meters. The column of fire moved towards the square with frightened people and burned 38 thousand people in a few minutes.
5. Sandstorms
This phenomenon occurs in sandy deserts when there is a strong wind. Sand, dust and soil particles rise to a fairly high altitude, forming a cloud that sharply reduces visibility. If an unprepared traveler gets caught in such a storm, he may die from grains of sand falling into his lungs. Herodotus described the story as 525 BC. e. In the Sahara, a 50,000-strong army was buried alive by a sandstorm. In Mongolia in 2008, 46 people died as a result of this natural phenomenon, and a year earlier two hundred people suffered the same fate.
Throughout the history of mankind, powerful earthquakes have repeatedly caused colossal damage to people and caused a huge number of casualties among the population...
6. Avalanches
From the snowy mountain peaks Snow avalanches occur periodically. Climbers especially often suffer from them. During the First World War, up to 80 thousand people died from avalanches in the Tyrolean Alps. In 1679, half a thousand people died from snow melting in Norway. In 1886, a major disaster occurred, as a result of which “ White death"claimed 161 lives. The records of Bulgarian monasteries also mention human casualties oh snow avalanches.
7. Hurricanes
In the Atlantic they are called hurricanes, and in Pacific Ocean typhoons. These are huge atmospheric vortices, in the center of which the strongest winds and sharply reduced pressure are observed. Several years ago, the devastating Hurricane Katrina swept over the United States, which particularly affected the state of Louisiana and the densely populated city of New Orleans, located at the mouth of the Mississippi. 80% of the city was flooded, and 1,836 people died. Famous destructive hurricanes steel also:
- Hurricane Ike (2008). The diameter of the vortex was over 900 km, and in its center the wind blew at a speed of 135 km/h. In the 14 hours that the cyclone moved across the United States, it managed to cause $30 billion worth of destruction.
- Hurricane Wilma (2005). This is the largest Atlantic cyclone in the entire history of weather observations. The cyclone, which originated in the Atlantic, made landfall several times. The damage it caused amounted to $20 billion, killing 62 people.
- Typhoon Nina (1975). This typhoon was able to breach China's Bangqiao Dam, causing the destruction of the dams below and causing catastrophic flooding. The typhoon killed up to 230 thousand Chinese.
8. Tropical cyclones
These are the same hurricanes, but in tropical and subtropical waters, representing huge atmospheric systems low pressure with winds and thunderstorms often exceeding a thousand kilometers in diameter. Near the surface of the earth, winds at the center of the cyclone can reach speeds of more than 200 km/h. Low pressure and wind cause the formation of a coastal storm surge - when colossal masses of water are thrown ashore at high speed, washing away everything in its path.
Occasionally, tsunami waves occur in the ocean. They are very insidious - in the open ocean they are completely invisible, but as soon as they approach the coastal shelf, they...
9. Landslide
Prolonged rains can cause landslides. The soil swells, loses stability and slides down, taking with it everything that is on the surface of the earth. Most often, landslides occur in the mountains. In 1920, the most devastating landslide occurred in China, under which 180 thousand people were buried. Other examples:
- Bududa (Uganda, 2010). Due to mudflows, 400 people died, and 200 thousand had to be evacuated.
- Sichuan (China, 2008). Avalanches, landslides and mudflows caused by an 8-magnitude earthquake claimed 20 thousand lives.
- Leyte (Philippines, 2006). The downpour caused a mudslide and landslide that killed 1,100 people.
- Vargas (Venezuela, 1999). Mudflows and landslides after heavy rains (almost 1000 mm of precipitation fell in 3 days) on the northern coast led to the death of almost 30 thousand people.
10. Ball lightning
We are accustomed to ordinary linear lightning accompanied by thunder, but ball lightning is much rarer and more mysterious. The nature of this phenomenon is electrical, but scientists cannot yet give a more accurate description of ball lightning. It is known that she can have different sizes and shape, most often yellowish or reddish luminous spheres. For unknown reasons, ball lightning often defies the laws of mechanics. Most often they appear before a thunderstorm, although they can also appear in absolute clear weather, as well as indoors or in an airplane cockpit. The luminous ball hovers in the air with a slight hiss, then can begin to move in any direction. Over time, it seems to shrink until it disappears completely or explodes with a roar. But the damage ball lightning can bring very limited.
Natural emergency - situation in certain territory or water area formed as a result of the occurrence of a source of natural emergency, which may entail or has entailed human casualties, damage to human health and (or) the environment natural environment, significant material losses and disruption of people's living conditions.
Natural emergencies are distinguished by the scale and nature of the source of their occurrence; they are characterized by significant damage and loss of life, as well as destruction material assets.
Earthquakes, floods, forest and peat fires, mudflows and landslides, storms, hurricanes, tornadoes, snow drifts and icing - all these are natural emergencies, and they will always be companions of human life.
In case of natural disasters, accidents and catastrophes, human life is subject to great danger and requires the concentration of all his spiritual and physical strength, meaningful and cold-blooded application of knowledge and skills to act in a particular emergency situation.
Landslide.
A landslide is a separation and sliding displacement of a mass of earthen and rocks downward under the influence of own weight. Landslides most often occur along the banks of rivers, reservoirs and on mountain slopes.
Landslides can occur on all slopes, but on clay soils they occur much more often; excessive moisture of the rocks is sufficient for this, so for the most part they disappear in the spring-summer period.
The natural reason for the formation of landslides is an increase in the steepness of the slopes, eroding their bases river waters, excessive moisture various breeds, seismic tremors and a number of other factors.
Mudflow (mudflow)
A mudflow (mudflow) is a rapid flow of great destructive force, consisting of a mixture of water, sand and stones, suddenly appearing in mountain river basins as a result of intense rains or rapid melting of snow. The causes of mudflows are: intense and prolonged downpours, rapid melting of snow or glaciers, breakthrough of reservoirs, earthquakes and volcanic eruptions, as well as the collapse of large amounts of loose soil into river beds. Mudflows pose a threat to populated areas, railways and highways and other structures located on their way. Possessing a large mass and high speed movement, mudflows destroy buildings, roads, hydraulic engineering and other structures, disable communication and power lines, destroy gardens, flood arable land, and lead to the death of people and animals. All this lasts 1-3 hours. The time from the occurrence of a mudflow in the mountains to the moment it reaches the foothills is often calculated at 20-30 minutes.Landslide (mountain collapse)
Landslide (mountain collapse) – separation and catastrophic fall large masses rocks, their overturning, crushing and rolling down on steep and steep slopes.
Collapses natural origin observed in the mountains, on sea shores and cliffs river valleys. They occur as a result of a weakening of the cohesion of rocks under the influence of weathering processes, erosion, dissolution and the action of gravity. The formation of landslides is promoted geological structure terrain, the presence of cracks and rock crushing zones on the slopes.
Most often (up to 80%), modern landslides are formed as a result of improper work, during construction and mining.
People living in hazardous areas, must know the sources, possible directions of movement of flows and the possible strength of these dangerous phenomena. If there is a threat of a landslide, mudflow or landslide, and if there is time, advance evacuation of the population, farm animals and property from threatening zones to safe places is organized.
Avalanche (snow avalanche)
An avalanche (snow avalanche) is a rapid, sudden movement of snow and (or) ice down steep mountain slopes under the influence of gravity and poses a threat to the life and health of people, causing damage to economic and environment. Snow avalanches are a type of landslide. When avalanches form, snow first slides down the slope. Then the snow mass quickly picks up speed, capturing more and more snow masses, stones and other objects along the way, developing into a powerful stream that rushes down at high speed, sweeping away everything in its path. The movement of the avalanche continues to flatter sections of the slope or to the bottom of the valley, where the avalanche then stops.
Earthquake
An earthquake is an underground tremors and vibrations of the earth's surface that arise as a result of sudden displacements and ruptures in the earth's crust or upper part of the earth's mantle and are transmitted over long distances in the form of elastic vibrations. According to statistics, earthquakes rank first in terms of economic damage caused and one of the first places in terms of the number of human casualties.
During earthquakes, the nature of the damage to people depends on the type and density of the settlement, as well as on the time the earthquake occurred (day or night).
At night, the number of victims is much higher, because... Most people are at home and relaxing. During the day, the number of affected people fluctuates depending on what day the earthquake occurred - on a weekday or on a weekend.
In brick and stone buildings, the following nature of injury to people prevails: injuries to the head, spine and limbs, compression of the chest, soft tissue compression syndrome, as well as injuries to the chest and abdomen with damage to internal organs.
Volcano
A volcano is a geological formation that appears above channels or cracks in the earth’s crust, through which hot lava, ash, hot gases, water vapor, and rock fragments are erupted onto the Earth’s surface and into the atmosphere.
Most often, volcanoes form at the junction of the Earth's tectonic plates. Volcanoes can be extinct, dormant or active. In total, there are almost 1,000 dormant and 522 active volcanoes on land.
About 7% of the world's population lives dangerously close to active volcanoes. More than 40 thousand people died as a result of volcanic eruptions in the 20th century.
The main damaging factors during a volcanic eruption are hot lava, gases, smoke, steam, hot water, ash, rock fragments, blast wave and mud-stone flows.
Lava is a hot liquid or very viscous mass that flows onto the surface of the Earth during volcanic eruptions. The lava temperature can reach 1200°C or more. Along with the lava, gases and volcanic ash are emitted to a height of 15-20 km. and at a distance of up to 40 km. and more. A characteristic feature of volcanoes is their repeated multiple eruptions.
Hurricane
A hurricane is a wind of destructive force and considerable duration. A hurricane occurs suddenly in areas with sharp changes atmospheric pressure. Hurricane speed reaches 30 m/s or more. In terms of its harmful effects, a hurricane can be compared to an earthquake. This is explained by the fact that hurricanes carry colossal energy; the amount of energy released by an average hurricane in one hour can be compared with the energy of a nuclear explosion.
Hurricane winds destroy strong and demolish light buildings, devastate sown fields, break wires and knock down power and communication lines, damage highways and bridges, break and uproot trees, damage and sink ships, and cause accidents in utility and energy networks.
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 strong storm called a storm.
A tornado is a strong small-scale atmospheric vortex with a diameter of up to 1000 m, in which air rotates at a speed of up to 100 m/s, which has great destructive power (in the USA it is called a tornado). In internal cavity The pressure of a tornado is always low, so any objects that are in its path are sucked in. average speed The tornado moves at 50-60 km/h, and as it approaches, a deafening roar is heard.
Storm
Thunderstorm is an atmospheric phenomenon associated with the development of powerful cumulonimbus clouds, which is accompanied by multiple electrical discharges between the clouds and earth's surface, thunder, heavy rain, often hail. According to statistics, 40 thousand thunderstorms occur in the world every day, and 117 lightning flashes every second.
Thunderstorms often go against the wind. Immediately before the onset of a thunderstorm, there is usually calm or the wind changes direction, sharp squalls occur, after which it begins to rain. However greatest danger represent “dry” thunderstorms, that is, not accompanied by precipitation.
blizzard
A snow storm is one of the types of hurricane, characterized by significant wind speeds, which contributes to the movement of huge masses of snow through the air, and has a relatively narrow range of action (up to several tens of kilometers). During a storm, visibility deteriorates sharply and may be interrupted. transport connection both intracity and intercity. The duration of the storm varies from several hours to several days.
Blizzards, blizzards, blizzards are accompanied by sudden changes in temperature and snowfall with strong gusts wind. Temperature changes, snow and rain at low temperature And strong wind, creates conditions for icing. Power lines, communication lines, roofs of buildings, various types of supports and structures, roads and bridges are covered with ice or wet snow, which often causes their destruction. Ice formations on the roads make it difficult, and sometimes even completely prevent the operation of road transport. Pedestrian movement will be difficult.
Main damaging factor such natural Disasters is the effect of low temperature on the human body, causing frostbite and sometimes freezing.
Floods
Floods are significant inundations of an area resulting from rising water levels in a river, reservoir or lake. Floods are caused by heavy rainfall, intense snow melting, and the breach or destruction of dams and dams. Floods are accompanied by loss of life and significant material damage.
In terms of frequency and area of distribution, floods rank first among natural disasters; in terms of the number of human casualties and material damage, floods rank second after earthquakes.
Flood– phase water regime river, which can be repeated many times in different seasons of the year, characterized by an intense, usually short-term increase in flow rates and water levels, and caused by rain or snowmelt during thaws. Successive floods can cause flooding. Significant flooding may cause flooding.
Catastrophic flood– a significant flood resulting from intense melting of snow, glaciers, and heavy rains, forming a strong flood, as a result of which there was mass death population, farm animals and plants, damage or destruction of material assets, and damage to the environment was caused. The term catastrophic flood is also applied to a flood that causes the same consequences.
Tsunami– giant sea waves resulting from the upward or downward displacement of extended sections of the seabed during strong underwater and coastal earthquakes.
The most important characteristic forest fire is the speed of its propagation, which is determined by the speed of advancement of its edge, i.e. burning stripes along the fire contour.
Forest fires, depending on the area of fire spread, are divided into ground fires, crown fires and underground fires (peat fires).
Ground fire is a fire that spreads across the ground and lower tiers forest vegetation. The fire temperature in the fire zone is 400-900 °C. Ground fires are the most frequent and account for up to 98% total number sunbathing
A crown fire is the most dangerous. It starts in strong winds and covers the tree crowns. The temperature in the fire zone rises to 1100°C.
An underground (peat) fire is a fire in which the peat layer of marshy and swampy soils burns. Peat fires are characterized by the fact that they are very difficult to extinguish.
The causes of fires in steppe and grain massifs can be thunderstorms, accidents of ground and air transport, accidents of grain harvesting equipment, Act of terrorism and careless handling of open fire. The most fire-hazardous conditions occur in late spring and early summer, when the weather is dry and hot.