Meteorological phenomena classification. Natural phenomena of meteorological origin

Meteorological phenomena are a natural phenomenon that is dangerous to human life and can cause significant damage to their economy. Today, such climate anomalies occur every day in different corners Earth, so it would be useful to learn more about them and familiarize yourself with the basic rules of behavior during disasters.

Natural hazards group 1

This group includes climate anomalies that may threaten human safety and property in the event of long duration or high intensity.

Examples of hazardous meteorological phenomena of category A1:

A1.1 - Extremely strong wind. Its gusts can reach speeds above 25 m/s.

A1.2 - Hurricane. This is a separate type of wind anomaly. Gust speeds can reach up to 50 m/s.

A1.3 - Squall. Sudden increase in wind (short-term). Gusts can reach up to 30 m/s.

A1.4 - Tornado. This is the most destructive and life-threatening natural phenomenon. A strong wind is localized into a funnel that is directed from the clouds to the ground.

The following meteorological hazards in this category are associated with precipitation:

A1.5 - Heavy rain. Heavy rain may not stop for very long for a long time. The amount of precipitation exceeds 30 mm in 1 hour.

A1.6 - Heavy mixed rain. Precipitation falls in the form of rain and sleet. There is a decrease in air temperature. The amount of precipitation can reach up to 70 mm in 12 hours.

A1.7 - Extremely heavy snow. This is solid precipitation, the amount of which in 12 hours can exceed 30 mm.

The following meteorological phenomena appear on a separate line:

A1.8 - Long rainfall. The duration of heavy rain is at least 12 hours (with minor breaks). Precipitation exceeds the 100 mm threshold.

A1.9 - Big city. Its diameter should be 20 mm or more.

The second group of natural hazards of category A1

This section includes climatic anomalies such as snowstorms, fog, severe icing, abnormal heat, etc.

Meteorological hazardous natural phenomena of the second group, category A1:

A1.10 - Heavy snowstorm. The wind carries snow at a speed of 15 m/s and above. At the same time, the visibility range is about 2 m.

A1.11 - Sandstorm. The wind carries dust and soil particles at a speed of 15 m/s and higher. Visibility range - no more than 3 m.

A1.12 - Fog-haze. Serious cloudiness of the air is observed due to a large accumulation of water particles, combustion products or dust. Visibility range - less than 1 m.

A1.13 - Heavy frost deposits. Its diameter (on the wires) is at least 40 mm.

The following meteorological phenomena of category A1 are associated with temperature changes:

A1.14 - Extremely severe frost. Values ​​vary by geographic location and time of year.

A1.15 - Abnormal cold. IN winter period for 1 week the air temperature remains below the meteorological norm by 7 degrees or more.

A1.16 - Extremely hot weather. Indicators maximum temperature depend on geographic location.

A1.17 - Abnormal heat. In the warm season, for 5 days or more the temperature remains above normal by at least 7 degrees.

A1.18 - Fire situation. Its indicator belongs to the fifth hazard class.

Natural hazards category A2

This group includes agrometeorological anomalies. Any phenomenon in this category can cause enormous damage agriculture.

Meteorological natural phenomena related to type A2:

A2.1 - Frosts. Air and soil temperatures drop sharply during the harvesting period or active growing season of crops.

A2.2 - Waterlogging of the soil. The soil at a depth of 100 mm is visually fluid or sticky (for 2 weeks).

A2.3 - Sukhovey. It is characterized by air humidity of less than 30%, temperature above 25 degrees and wind of 7 m/s.

A2.4 - Atmospheric drought. No precipitation at an air temperature of 25 degrees for 1 month.

A2.5 - Soil drought. In the top layer of soil (20 cm), the moisture coefficient is less than 10 mm.

A2.6 - Abnormally early appearance of snow cover.

A2.7 - Soil freezing ( top layer up to 20 mm). Duration - from 3 days.

A2.8 - in the absence of snow cover.

A2.9 - Light frost with high snow cover (more than 300 mm). The temperature is not lower than -2 degrees.

A2.10 - Ice cover. Frost crust with a thickness of 20 mm. The duration of soil coverage is at least 1 month.

Rules of conduct during hazardous meteorological phenomena

During climate phenomena It is important to remain calm and reasonable and not to panic.

Wind meteorological natural phenomena (examples: storm, hurricane, tornado) are dangerous to human life only in the immediate vicinity of the source of the anomaly. Therefore, it is strongly recommended to hide in specially equipped underground shelters. Do not approach windows, as there is a high risk of injury from glass fragments. It is prohibited to be under open air, on bridges, near power lines.

During abnormal periods, movement on the roadway should be limited and rural areas. It is also recommended to stock up on food and water. Stay away from power lines and steep roofs.

In case of flooding, it is necessary to take a safe place on a hill and mark it for subsequent detection by rescuers. It is not recommended to stay in one-story rooms, as the water level can rise sharply at any minute.

Record weather anomalies

Over the past 20 years, nature has presented humanity with many surprises. These are all kinds of dangerous weather events (examples: huge hail, record high winds, etc.) that have claimed lives and caused maximum damage to the economy.

In May 1999, the strongest gust of wind on the Fagit scale was recorded. The tornado was classified as an F6. The wind speed reached 512 km/h. The tornado destroyed hundreds of homes and killed dozens of people.

In the summer of 1998, about 30 m of snow fell on the famous Mount Baker in Washington state. Precipitation continued for several months.

The highest temperatures were recorded in Libya in September 1992 (58 degrees Celsius).

Most big hail took place in the summer of 2003 in Nebraska. The diameter of the largest specimen was 178 mm, and its falling speed was about 160 km/h.

The rarest meteorological phenomena

In 2013, the morning after, visitors to the Grand Canyon witnessed a unique natural phenomenon called an inversion. Thick fog descended into the crevices, forming a whole waterfall of clouds.

Also in 2013, Ohioans saw in their backyards a huge portion of the area surrounding their city, all the way to the Canadian border. This phenomenon is called super-refraction, when light rays are bent by air pressure and reflect objects located at vast distances in the distance.

In 2010, people in Stavropol could see multi-colored snow. The city was covered in brown and purple snowdrifts. The snow turned out to be non-toxic. Scientists have found that the precipitation was colored in the upper layers of the atmosphere, mixed with particles of volcanic ash.

Lecture

Emergency natural character and measures to reduce possible impacts from them

1. Theoretical provisions

2. Natural phenomena meteorological origin

3. Natural phenomena of geophysical origin

4. Natural phenomena of geological origin

5. Natural phenomena of cosmic origin

6. Natural phenomena biological origin

Theoretical provisions

Natural emergencies have threatened the inhabitants of our planet since the beginning of civilization. The amount of damage depends on the intensity of natural phenomena, the level of development of society and living conditions. Natural phenomena can be extreme, extraordinary and catastrophic. Catastrophic natural phenomena are called natural disasters. Natural disaster is a catastrophic natural phenomenon that can cause numerous casualties and cause significant material damage. Total number natural disasters all over the world all the time increases. Natural phenomena are most often sudden and unpredictable and also they can wear explosive and impetuous character. Natural phenomena can occur regardless from each other (for example, avalanches and natural fires) and during interaction(eg earthquake and tsunami). Humanity is not so helpless in the face of the elements. Some phenomena can be predicted, and some can be successfully resisted. To effectively counter natural emergencies, knowledge is required composition of the event, historical chronicle and local characteristics of natural hazards. Protection from natural hazards can be active(for example, construction of engineering structures) and passive(use of shelters, hills. Due to their occurrence, natural phenomena are currently divided into six groups.

Natural phenomena of meteorological origin

Meteorology is a science that studies changes occurring in the Earth's atmosphere. These are temperature, humidity, atmospheric pressure, air currents (wind), change magnetic field Earth. The movement of air relative to the ground is called by the wind. Wind strength is assessed on the 12-point Beaufort scale (at a standard height of 100 meters above an open, flat surface).

Storm - prolonged and very strong wind, the speed of which exceeds 20 m/s.

Hurricane – wind of great destructive power and considerable duration, the speed of which is 32 m/s (120 km/h). Hurricane-force winds accompanied by heavy precipitation, in Southeast Asia called a typhoon.

Tornado – or a tornado - atmospheric vortex, originating in a thundercloud and then spreading in the form of a dark arm or trunk towards the surface of land or sea. The principle of operation of a tornado resembles the operation of a vacuum cleaner.

Dangers for people during such natural phenomena are the destruction of houses and structures, overhead power and communication lines, ground pipelines, as well as the defeat of people by debris from destroyed structures, glass fragments flying from high speed. In snowy and dust storms snow drifts and dust accumulations on fields, roads and populated areas, as well as water pollution, are dangerous. Air movement is directed from high pressure to low. An area is forming low pressure with a minimum in the center, which is called cyclone. The cyclone is several thousand kilometers across. The weather during a cyclone is predominantly cloudy, with increased wind. During the passage of a cyclone, weather-sensitive people complain of deterioration in their health.

Severe frosts - characterized by a decrease in temperature over several days by 10 degrees or more below the average for a given area.

Ice – a layer of dense ice (several centimeters) that forms on the surface of the earth, sidewalks, roadways, and on objects and buildings when supercooled rain and drizzle (fog) freeze. Ice is observed at temperatures from 0 to 3 C. Alternatively, freezing rain.

Black ice - This is a thin layer of ice on the surface of the earth that forms after a thaw or rain as a result of cold temperatures, as well as the freezing of wet snow and raindrops.

Dangers. Increase in the number of road accidents and injuries among the population. Disruption of vital functions due to icing of power lines and contact networks of electric transport, which can lead to electrical injuries and fires.

Blizzard(blizzard, blizzard) is a hydrometeorological disaster. Associated with heavy snowfall, with wind speeds above 15 m/s and snowfall duration of more than 12 hours

Dangers for the population consists of road drifts, settlements and individual buildings. The drift height can be more than 1 meter, and in mountainous areas up to 5-6 meters. Visibility on roads may be reduced to 20-50 meters, as well as destruction of buildings and roofs, power and communications breaks.

Fog - accumulation of small water droplets or ice crystals in the ground layer of the atmosphere, reducing visibility on roads.

Dangers. Reduced visibility on the roads disrupts transport, which leads to accidents and injuries among the population.

Drought – prolonged and significant lack of precipitation, more often when elevated temperature and low humidity.

Extreme heat - characterized by an increase average annual temperature ambient air by 10 degrees or more for several days

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

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

In the upper troposphere, on the contrary, above the equator, where ascending air currents predominate, the pressure is high, and above the poles it is low. Air is constantly moving out of the area high blood pressure to the region low blood pressure. Therefore, the air rising above the equator grows 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 degrees north and south latitudes, forming areas of high pressure in both hemispheres.

Large volumes of air in the troposphere that have homogeneous properties are called air masses. The properties of air masses depend on the territories over which they were formed. As air masses move, they retain their properties for a long time, and when they meet, they interact with each other. The movement of air masses and their interaction determine the weather in those places where these air masses arrive. The interaction of various air masses leads to the formation of moving atmospheric vortices in the troposphere - cyclones and anticyclones.

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

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

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

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

Wind speed is measured by a special device - an anemometer

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

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

Table 12

Beaufort scale

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

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

During hurricanes, the width of the zone of catastrophic destruction reaches several hundred kilometers (sometimes thousands of km). The hurricane lasts 9-12 days, causing a large number of casualties and destruction. The transverse size of a tropical cyclone (also called a tropical hurricane or typhoon) is several hundred kilometers. The pressure in hurricanes drops much lower than in an extratropical cyclone. At the same time, the wind speed reaches 400-600 km/h. As surface pressure continues to fall, the tropical disturbance becomes a hurricane when wind speeds begin to exceed 64 knots. A noticeable rotation develops around the hurricane's center as spiral bands of precipitation swirl around the eye of the hurricane. The heaviest precipitation and strongest winds are associated with the eye wall.

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

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

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

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

q= 0,5pV²(kPa)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

natural meteorological atmospheric

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