Hazardous weather phenomena. Weather phenomena and human safety Transitions in snow and rain

The Earth is fraught with many unusual and sometimes inexplicable phenomena, and from time to time all sorts of phenomena and even cataclysms occur throughout the globe, most of which can hardly be called ordinary and familiar to humans. Some cases have completely understandable reasons, but there are also those that even experienced scientists have not been able to explain for many decades. True, this kind of natural disasters do not happen often, only a few times during the year, but, nevertheless, humanity’s fear of them does not disappear, but, on the contrary, grows.

The most dangerous natural phenomena

These include the following types of disasters:

Earthquakes

This is a dangerous natural phenomenon in the ranking of the most dangerous natural anomalies. Tremors of the earth's surface, occurring in places where the earth's crust breaks, provoke vibrations that turn into seismic waves of significant power. They are transmitted over considerable distances, but become strongest near the immediate source of tremors and provoke large-scale destruction of houses and buildings. Since there are a huge number of buildings on the planet, the number of victims runs into the millions. Over all time, earthquakes have affected many more people in the world than other disasters. Over the past ten years alone, more than seven hundred thousand people have died from them in different countries of the world. Sometimes the tremors reached such strength that entire settlements were destroyed in an instant.

Tsunami waves

Tsunamis are natural disasters that cause a lot of destruction and death. Waves of enormous height and strength that arise in the ocean, or in other words, tsunamis, are a consequence of earthquakes. These giant waves usually occur in areas where seismic activity is significantly increased. The tsunami moves very quickly, and once it gets aground, it begins to rapidly grow in length. Once this huge fast wave reaches the shore, it can destroy everything in its path in a matter of minutes. The destruction caused by a tsunami is usually large-scale, and people who are caught by surprise by the cataclysm often do not have time to escape.

Ball lightning

Lightning and thunder are common things, but a type such as ball lightning is one of the most terrible natural phenomena. Ball lightning is a powerful electric discharge of current, and it can take on absolutely any shape. Typically, this type of lightning looks like balls of light, most often reddish or yellow in color. It is curious that these lightning completely ignore all the laws of mechanics, appearing out of nowhere, usually before a thunderstorm, inside houses, on the street or even in the cockpit of an airplane that is flying. Ball lightning hovers in the air, and does so very unpredictably: for a few moments, then it becomes smaller, and then disappears completely. It is strictly forbidden to touch ball lightning; moving when encountering it is also undesirable.

Tornadoes

This natural anomaly is also one of the most terrible natural phenomena. Typically, a tornado is an air flow that twists into a kind of funnel. Outwardly, it looks like a columnar, cone-shaped cloud, inside of which air moves in a circle. All objects that fall into the tornado zone also begin to move. The speed of air flow inside this funnel is so enormous that it can easily lift very heavy objects weighing several tons and even houses into the air.

Sandstorms

This type of storm occurs in deserts due to strong winds. Dust and sand, and sometimes soil particles carried by the wind, can reach several meters in height, and in the area where the storm breaks out, there will be a sharp decrease in visibility. Travelers caught in such a storm risk death because sand gets into their lungs and eyes.

Bloody Rains

This unusual natural phenomenon owes its threatening name to a strong waterspout, which sucked out particles of red algae spores from the water in reservoirs. When they mix with the water masses of a tornado, the rain takes on a terrible red hue, very reminiscent of blood. This anomaly was observed by residents of India for several weeks in a row; rain the color of human blood caused fear and panic among people.

Fire tornadoes

Natural phenomena and disasters are most often unpredictable. These include one of the most terrible - a fire tornado. This type of tornado is already dangerous, but , if it occurs in a fire zone, it should be even more feared. Near several fires, when a strong wind occurs, the air above the fires begins to warm up, its density becomes less, and it begins to rise upward along with the fire. In this case, the air flows twist into peculiar spirals, and the air pressure acquires enormous speed.

The fact that the most terrible natural phenomena are poorly predicted. They often come suddenly, taking people and authorities by surprise. Scientists are working to create advanced technologies that can predict upcoming events. Today, the only guaranteed way to avoid the “vagaries” of the weather is to move to areas where such phenomena are observed as rarely as possible or have not been recorded before.

5th grade

Weather events and human safety

Weather - what is meant by it?

You already know that the Earth is surrounded by a shell of air - atmosphere. The air shell of the Earth is very mobile, unstable and changeable. Changes in the Earth's air cover determine the weather.

Weather - This is the state of the atmosphere in a certain place and at a certain time.

Basic weather indicators:

• First indicator- This temperature ambient air, which fluctuates depending on the season, time of day and temperature of the air mass over a certain area.
• Second important indicator- This Atmosphere pressure , which influences air movement - wind.

Third indicator it's in eter Wind is characterized by the direction (where it blows from) and the speed of air movement.

Depending on the speed of air movement, there are:

Fresh breeze - wind speed from 5 to 10 m/s (18-36 km/h),

Storm (storm) - wind whose speed more than 20 m/s (72 km/h)

A short-term increase in wind up to 30 m/s is called - squall

Hurricane - wind whose speed is more than

30 m/s (more than 100 km/h)

Storm - stormy weather with rain, thunder and lightning .

• Thunderstorms are associated with the development of cumulonimbus clouds, with the accumulation of large amounts of electricity in them. Multiple electrical discharges occurring in clouds or between clouds and ground, are called lightning.
• A thunderstorm is always accompanied by peals of thunder and gusts of wind.

the main sign of an approaching thunderstorm .

is a collection of powerful cumulonimbus clouds that move quickly and soon occupy the entire sky.

Ice - this is a layer of dense ice that forms on the earth's surface (sidewalks, roadways) and on objects (trees, wires, houses, etc.) when drops of supercooled rain and drizzle freeze, usually at air temperatures from 0 to -3 ° C .

Ice thickness during icy conditions can reach several centimeters.

Black ice - This is a thin layer of ice that formed on the earth's surface after a thaw or rain as a result of a cold snap, as well as after the freezing of wet snow.

Snow drift is a natural phenomenon associated with heavy snowfall at speed winds over 15 m/s (54 km/h) and duration of snowfall more than 12 hours .

Blizzard - This is the transfer of snow by wind in the surface layer of air. Often a blizzard is accompanied by snowfall.

Blizzard - strong wind with snowfall.

• Study §3.1
• Learn the rules of behavior in the event of hazardous natural phenomena.
• Write down folk signs (at least 5 signs) indicating a change in weather.

• 1 picture - http://images.clipartpanda.com/weather-clip-art-inclement_weather_Vector_Clipart.png
• 2 picture - http://3.bp.blogspot.com/-PQ3V-ttpS1s/UopKK13sZWI/AAAAAAAAPdo/HzK1xwbp0KY/s1600/g%C3%BCne%C5%9F+resimleri+%2827%29.png
• 3 picture - http://yt3.ggpht.com/-Yl76pioRj5A/AAAAAAAAAAI/AAAAAAAAAAA/mH4FKPebItE/s900-c-k-no/photo.jpg
• 4 picture - Forshtat M.L. Learn to be a pedestrian. A textbook on traffic rules for 6th grade. Rice. D.G. Maistrenko/ Cover design by A.S. Andreeva. - St. Petersburg: Publishing House "MiM", 1998.
• 5 picture - Forshtat M.L. Learn to be a pedestrian. A textbook on traffic rules for 6th grade. Rice. D.G. Maistrenko/ Cover design by A.S. Andreeva. - St. Petersburg: Publishing House "MiM", 1998.
• 6 picture - Basics of life safety. 5th grade: educational. for general education organizations with adj. per electron carrier / A.T.Smirnov, B.O. Khrennikov; ed. A.T. Smirnova; Ross. acad. Sciences, Ross. acad. education, publishing house "Enlightenment". – 3rd ed. – M.: Education, 2014.
• 7 picture - Basics of life safety. 5th grade: educational. for general education organizations with adj. per electron carrier / A.T.Smirnov, B.O. Khrennikov; ed. A.T. Smirnova; Ross. acad. Sciences, Ross. acad. education, publishing house "Enlightenment". – 3rd ed. – M.: Education, 2014.
• 8 picture - http://picnations.tk/wp-content/uploads/2015/09/Raindrops-on-Leaf-Wallpaper.jpg
• 9 picture - http://www.province.ru/tyumen/media/k2/items/cache/5003d452a8da016f3ed02a6385cf54e8_XL.jpg
• 10 picture - http://st.depositphotos.com/1027309/2999/v/950/depositphotos_29992109-Thermometer-snow-sun.jpg
• 11 picture - http://st2.depositphotos.com/1000489/5709/v/950/depositphotos_57094631-Owl-reading-a-book.jpg

Slide 1

Slide 2

Weather is the main factor on which human safety in natural conditions depends. Some weather phenomena significantly complicate a person's stay in the natural environment. When going on a hike, you need to find out how the weather changes in the places of your planned vacation at different times of the year. Weather is a major factor

Slide 3

From the experience of organizing active recreation in nature, it has been established that for any area and each type of tourist trip (hiking, mountain, water, skiing), the most favorable and unfavorable seasons in terms of weather conditions can be identified. We know that...

Slide 4

Thus, for amateur mountain hikes, the second half of summer (July - August) is considered the most favorable season in almost all regions of the country. For ski tourism in the middle zone, March is preferable, and in the northern regions - March - April. For mountain and ski trips

Slide 5

Experienced tourists advise that in case of short-term intense precipitation (heavy rain), stop in the first convenient place and wait out the bad weather in a shelter, under an awning or a cape. In bad weather

Slide 6

You can continue driving in rain and snow on a technically simple section, along trails, on flat terrain, covered with a cape. Immediately after crossing in the rain (or snow), it is necessary to organize a bivouac, preferably in a shelter, where you can make a fire, change clothes, and dry wet clothes and shoes. Transitions in snow and rain

Slide 7

Particular care must be taken during thunderstorms. This weather phenomenon is associated with the development of cumulonimbus clouds and the accumulation of large electrical charges in them. The greatest danger to humans is a direct lightning strike. What to do during a thunderstorm

Slide 8

Lightning is a giant electrical discharge that occurs between thunderclouds or between clouds and the ground. Currents generated in the ground when lightning strikes the earth's surface are also dangerous. Lightning

Slide 9

The harbingers of a thunderstorm are powerful cumulonimbus clouds, multiple flashes of lightning, and rumbles of thunder. Immediately before the start of a thunderstorm, there is usually a lull or the wind changes direction, then the wind suddenly increases sharply (squall) and the rain begins. Harbingers

Slide 10

- If you are on a hill (on a ridge, hill, steep slope) when a thunderstorm is approaching, you need to go down as quickly as possible to avoid being struck by lightning. - If you are in the water, you must quickly go to shore. - In the forest, it is best to hide among low trees with dense undergrowth. - Remember that among trees, birch and maple are less susceptible to direct lightning strikes, while oak and poplar are the most susceptible. First measures

Slide 11

In open areas, you should choose sandy or rocky areas; you can hide in a dry hole, ditch, or ravine. In the mountains, it is undesirable to seek shelter from a thunderstorm in small grottoes (shallow caves with a wide entrance), rock holes, or depressions, as there is a danger of being struck by currents formed in the ground after a lightning strike. Taking cover

Slide 12

If you still had to take refuge in a cave, grotto, or large depression, you cannot be at the entrance or in the far corner of such a place; a person’s position is safe when the distance between him and the walls is at least 1 m. In a cave

Slide 13

During a thunderstorm, you must not: position yourself next to a railroad track, near a body of water, or near a tall object (tree); lean your head, back or other parts of your body against the surface of rocks or tree trunks; stop at the edges of the forest and forest clearings. Remember!

Slide 14

In a snowstorm, with strong wind and cold, a person’s normal breathing is disrupted, the heat-protective properties of clothing are reduced, due to poor visibility, he loses orientation, can get lost, run out of strength and die. What to do during a blizzard

Slide 15

What to do during a snowstorm A snowstorm does not come suddenly. Before it begins, there is an increase in air temperature and a gradual increase in wind speed. A harbinger of a blizzard is the appearance of a dark gray or black cloud growing on the horizon with changing outlines. The wind gradually intensifies and becomes gusty, which lifts the snow and disperses the drifting snow. A cloud covers the entire sky, and a blizzard begins.

Slide 16

What to do during a blizzard It is best to wait out the blizzard in a bivouac camp. If a group is moving along the route when a blizzard approaches, it is necessary to immediately stop, set up camp and wait for it to end.

Slide 17

What to do during a blizzard The primary task facing a group of tourists before or after the onset of a blizzard is setting up a bivouac. When setting up a tent, you should find at least partial shelter from the wind. The tent is installed with the entrance on the leeward side, its guy ropes are secured by sticking them into the snow with skis or ski poles. After setting up the tent, backpacks are brought in and placed at the back windward wall and in the corners of the tent. Signs of worsening weather If the day is clear, but clouds thicken in the evening, then rain or a change in weather should be expected. Wavy (altocumulus) clouds that resemble ripples or wave crests are a sure sign of severe weather within a few hours. The air temperature rises slightly in winter and warming sets in. In summer, the difference between air temperature during the day and at night decreases; in the evening it is warmer than during the day. The wind intensifies, especially in the evening, and the regular daily changes in local winds are disrupted. Cloudiness increases, clouds move in the opposite direction or across the direction in which the wind blows at the earth's surface. The sun sets in a cloud, the evening dawn has a bright red color.

Slide 20

Questions and tasks Why do you need to know the weather forecast before going outdoors? How can you ensure your protection from precipitation in your native conditions? How dangerous is a thunderstorm for a person in natural conditions? How can you ensure your safety if a thunderstorm finds you outdoors? 5. What precautions should you take to protect yourself from a snowstorm?

To predict hazardous phenomena, Roshydromet has developed criteria - using them, experts determine the degree of danger of an impending or already occurring disaster. A total of 19 weather phenomena have been identified that may pose a serious threat.

Element No. 1: wind

Very strong wind(at sea there is a storm). The speed of the element exceeds 20 meters per second, and with gusts it increases by a quarter. For high-altitude and coastal areas, where winds are more frequent and intense, the standard is 30 and 35 meters per second, respectively.

In Russia, Primorye, the North Caucasus and the Baikal region suffer from storms more often than other regions. The strongest winds blow on the Novaya Zemlya archipelago, the islands of the Sea of ​​Okhotsk and in the city of Anadyr on the edge of Chukotka: air flow speeds often exceed 60 meters per second.

Hurricane- the same as a strong wind, but even more intense - with gusts the speed reaches 33 meters per second. During a hurricane, it is better to be at home - the wind is so strong that it can knock a person off his feet and cause injury.

The hurricane on May 29 of this year in Moscow became the largest in terms of the number of victims in the last hundred years. During the hurricane on May 29, wind speeds in some areas of the capital reached 25 m/s. More than 10 people were killed, more than a hundred were injured.

Squall- wind speed of 25 meters per second, not weakening for at least a minute. It poses a threat to life and health and can damage infrastructure, cars and houses.

Tornado- a vortex in the form of a pillar or cone, moving from the clouds to the surface of the Earth. On July 31, 2011, in Blagoveshchensk, Amur Region, a tornado overturned three trucks, damaged more than 50 support poles, roofs of houses, non-residential buildings and broke 150 trees.

An encounter with a vortex may be the last in your life: inside its funnel, the speed of air flows can reach 320 meters per second, approaching the speed of sound (340.29 meters per second), and the pressure can drop to 500 millimeters of mercury (the norm is 760 mm Hg). st). Objects within the range of action of this powerful “vacuum cleaner” rise into the air and rush through it at great speed.

frosts called a temporary decrease in soil or air temperature near the ground to zero (against the background of positive average daily temperatures).

Severe frost is recorded when the temperature reaches a dangerous value. Each region, as a rule, has its own.

If in the period from October to March the average daily temperature is seven degrees below the long-term norm, then the abnormal cold. Such weather leads to accidents in housing and communal services, as well as to the freezing of agricultural crops and green spaces.

Element No. 2: water

Heavy rain. If more than 30 millimeters of precipitation falls in an hour, such weather is classified as heavy rain. It is dangerous because the water does not have time to sink into the ground and flow into the rain drain. Heavy rainfall forms powerful streams that paralyze traffic on the roads. By eroding the soil, water masses bring down metal structures to the ground. In hilly areas or areas dissected by ravines, heavy rainfall increases the risk of mudflows.

If at least 50 millimeters of precipitation falls in 12 hours, meteorologists classify this phenomenon as "Very heavy rain", which can also lead to the formation of mudflows. For mountainous areas, the critical indicator is 30 millimeters, since the likelihood of catastrophic consequences is higher there.

Powerful mud flow with fragments of stones poses a mortal danger: its speed can reach six meters per second, and the “head of the element”, the leading edge of the mudflow, is 25 meters in height.

In July 2000, a powerful mudflow hit the city of Tyrnyanz in Karachay-Cherkessia. 40 people were missing, eight died, and another eight were hospitalized. Residential buildings and city infrastructure were damaged.

Continuous heavy rain. Precipitation that falls over half or a whole day should exceed 100 millimeters, or 120 millimeters in two days. For rain-prone areas, the norm is 60 millimeters.

The likelihood of flooding, washout and mudflows increases sharply during prolonged heavy rain.

Very heavy snow. This type of dangerous phenomenon means heavy snowfall, resulting in over 20 millimeters of precipitation in 12 hours. This amount of snow blocks roads and makes it difficult for cars to move.

hail It is considered large if the diameter of the ice balls exceeds 20 millimeters. This weather phenomenon poses a serious risk to property and human health. Hailstones falling from the sky can damage cars, break windows, destroy vegetation and destroy crops.

In August 2015, hail struck the Stavropol region, accompanied by heavy rain and wind. Eyewitnesses filmed hailstones the size of a chicken egg and five centimeters in diameter on their smartphones!

Heavy snowstorm they call a weather phenomenon in which for half a day the visibility of flying snow is up to 500 meters, and the wind speed does not fall below 15 meters per second. When disaster strikes, driving cars becomes dangerous and flights are cancelled.

Heavy fog or haze, are conditions under which for 12 hours or more visibility is from five to zero meters. The reason for this may be a suspension of tiny drops of water with a moisture content of up to one and a half grams of water per cubic meter of air, soot particles and tiny ice crystals.

Meteorologists determine atmospheric visibility using a special technique or using a transmissometer device.

Severe icy conditions. This weather phenomenon is recorded by a special device - an ice machine. Among the characteristic features of this bad weather are ice 20 millimeters thick, wet, non-melting snow 35 millimeters high, or frost half a centimeter thick.

Ice provokes many accidents and leads to casualties.

Element No. 3: earth

Dust storm recorded by meteorologists when, for 12 hours, dust and sand, carried by winds at a speed of at least 15 meters per second, impair visibility at a distance of up to half a kilometer.

Element No. 4: fire

Abnormal heat is recorded by meteorologists when, during the period from April to September, for five days, the average daily temperature is seven degrees higher than the climatic norm of the region.

The UN Office for Disaster Risk Reduction noted that from 2005 to 2014, more than 7,000 people died from the effects of heat waves.

Heatwave— the temperature exceeds the established dangerous threshold in the period from May to August (the critical value is different for each territory).

This leads to droughts, increased fire danger and heat strokes.

Extreme fire hazard. This type of dangerous phenomenon is declared at high air temperatures associated with a lack of precipitation.

Dangerous meteorological phenomena are atmospheric phenomena that can cause serious damage to the national economy, and under certain conditions, to the environmental resources of the territory. In Belarus, such phenomena include:

– squall and strong wind with a maximum speed of 15 - 29 m/s or gusts up to 15 - 34 m/s;

– rain or rain with snow with a precipitation amount of 15 − 49 mm;

– snow with a precipitation amount of 7–19 mm of water layer, which falls in no more than 12 hours;

– hail with a hailstone diameter of 6 − 19 mm;

– all thunderstorms;

– fog with visibility no more than 500 m and duration over 3 hours;

– a snowstorm with a wind speed of 11 - 14 m/s, lasting 3 hours or more;

– ice with sediment thickness of 6 − 19 mm; sticking of wet snow - 11 − 34 mm;

– frost - 50 mm or more;

– icy conditions;

– frosts on the soil surface or in the air during the growing season;

– a sharp transition (by 10 °C or more) of air temperature through 0 °C in spring or autumn;

– cases of extreme heat or frost. If the phenomenon exceeds the upper limits of intensity, then it goes into the category of especially dangerous meteorological phenomena. In Belarus, 20–60 days with dangerous meteorological phenomena are possible annually at each location. Among them, thunderstorms (about 50% of cases), fog (about 25%), frosts, blizzards, and strong winds predominate.
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Property, crops and gardens are subject to insurance against dangerous meteorological influences.

Fog– the presence of a large number of small drops of water in the air (in liquid or frozen form), which leads to a decrease in the meteorological visibility range to 1000 m or less. The number of days with fog increases with increasing altitude. The maximum number of days with fog (140) was observed in 1964 in ᴦ. Novogrudok. The cold season accounts for 60–80% of all days with fog in a year. Fogs often appear before sunrise and dissipate a few hours after sunrise. The average continuous length of fog during the cold period is about 10 hours. Moreover, in some cases, fogs can last for several days in a row (in Minsk in January 1971 - 79 hours, in Novogrudok in December 1959 - 105 hours).

Lightning - an electrical discharge in the atmosphere between clouds or a cloud and the ground. More than 99% of lightning occurs between April and September. On average, in the summer months there are 4–7, and in the south 5–8 days with lightning. The area of ​​the area covered by lightning is on average 500–600 km 2 , and only in 25% of cases the area of ​​the lightning area exceeds 2000 km 2 . On the territory of the republic, in each summer month there are on average about 20 days when lightning is observed at at least one point. Every year you can expect 3-4 days when lightning is observed in more than 20% of the territory.

Ice- a layer of dense ice that forms on objects when supercooled drops or frost freeze (must be distinguished from glaze - ice or icy snow on the surface). At higher altitudes, power lines and communication lines, ice is observed more often. From November to March, ice is observed almost annually for 2–4 days per month (in March – 1). The largest number of days with ice observed is approximately twice the average shown on the map. The number of days with ice increases with altitude and the greatest frequency is observed on the Novogrudok Upland, here in the winter of 1959/60. there were 63 days with ice.

Strong wind and squall. A squall is a sharp short-term increase in wind, an air vortex with a horizontal axis. Characterized by high speed and rapid changes in wind direction. On average, at a particular point, squalls are observed once every 5 years, the most probable speed is 15–20 m/s. In general, the republic annually experiences 3–5 days with destructive squalls (wind speed 25–30 m/s). Particularly dangerous is an increase in wind speed up to 25 m/s.

Thaw– increase in air temperature in winter to positive values. Thaws are dangerous for wintering crops; they can cause destruction of the exterior decoration of buildings and lead to the development of winter floods. They are observed almost every year during all winter months. Thaws prevail, in which the temperature does not exceed 2˚С, but approximately once every 20 years, warming can be expected in December to 8–13˚С, and in January and February – to 5–19˚С, in February 1990 ᴦ. – 16–17˚С (higher values ​​in the south and west). More than 50% of days with thaws have a positive average daily temperature.

Blizzard– wind transfer of snow from the surface of the snow cover; Most often (3–8 days per month) snowstorms are observed in January and February. Usually a snowstorm lasts up to 6–7 hours, but at times it can last for several days (in February 1956 in Vitebsk - 5.5 days, in February 1960 in Mozyr - more than 4 days). The total length during the winter ranges from 60–80 hours in the south to 150–190 hours in the north and west. Particularly dangerous are extended snowstorms (more than 12 hours) with high wind speeds (more than 15 m/s), which leads to a severe deterioration in visibility (less than 50 m). Such snowstorms occur once every 3–6 years. The greatest extent of such snowstorms was observed in February 1960. in Mozyr (more than 100 hours), in Gomel (76 hours).

hail- precipitation that falls in the form of dense pieces of ice of various shapes and sizes. Hail with a diameter of 2 cm or more is especially dangerous. At a single point, such hail is a rare phenomenon (once every 40–50 years), but in general, on the territory of the republic there are 4–5 days with such hail every year. Particularly dangerous hail is more often observed in elevated areas and the more forested south of the republic. In June 1953 ᴦ. In the Braslav region, hail with individual hailstones measuring 8–10 cm was observed.

Heavy rains. Rain with a daily rainfall of 15 mm or more is considered unsafe; with a daily rainfall of 50 mm or more, rain is considered especially dangerous. Unsafe rains at each point are observed almost every year, and in 1977 ᴦ. in Novogrudok there were 15 cases with such rains. Particularly unsafe ones are observed much less frequently, approximately once every 8–10 years (more often in the southwest). The maximum amount of precipitation was observed on August 6, 1970, in Bobruisk, when 146 mm fell in 5 hours.

Frost – lowering the temperature of the air or soil surface in the warm season to 0˚C and below. Frosts in Belarus are most often advective-radiative; they arise as a result of the penetration of cold air and its further cooling in partly cloudy weather due to cooling of the soil as a result of night radiation. More often, radiation frosts are observed in lower areas. In the air above drained peat bogs and on the surface of such peat bogs, the frequency of years with such frosts in May is almost twice as high as for mineral soils. Usually the number of days with frosts in a ten-day period (May) does not exceed three. The minimum temperature during frosts, as a rule, is not lower than –5˚С. Frosts in the air more often occur simultaneously on no more than one third of the entire area of ​​the republic. Moreover, in 20–25% of cases they can spread to 70% of the territory. And in May 1980 ᴦ. frosts were observed in all three decades and covered 80–95% of the territory.

Drought– a combination of high air temperatures, lack of precipitation, low air humidity and low moisture reserves in the soil for one month or more, leading to a significant reduction in yield or death of agricultural crops.
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As a rule, to identify a dry period, the following basic criteria are accepted: duration - 30 or more days, daily precipitation - no more than 5 mm, maximum air temperature - +25°C and above, in more than half of the days of the period .

Droughts in Belarus most often do not cover a large area; in about half of the cases their area of ​​distribution does not exceed 10% of the territory. Once every 7–12 years, droughts in at least one month cover more than 50% of the country's area. Such extensive droughts can span a two-month period once every 15–20 years.

Although the criterion for identifying drought is a dry period of more than 30 days, plants may begin to experience moisture deficiency if there is no rainfall, as is known, for a shorter period of time. In this regard, to complete the picture, it is advisable to consider rainless periods when for at least 10 consecutive days the daily precipitation amounts do not exceed 1 mm. From April to October, an average of 3–4 dangerous rainfall events are observed in each location in Belarus. The average continuous duration of rainless periods is 14–18 days, with a slight increase towards the south. In some years, the continuous duration of rainlessness can significantly exceed average values. Lack of rain lasting more than 20 days occurs about 7 times, and more than 30 days - up to 2 times a decade. Rainless periods are very often (in more than 80% of cases) combined with elevated air temperatures relative to average values, which increases the risk of droughts during such periods. In this case, the temperature increase should be quite significant: in half of the cases more than 2°C, and in 17% - more than 4°C.

In addition to the negative impact on agricultural crops, during severe droughts conditions are created for the deterioration of the epidemiological situation and the mass reproduction of forest pests, and the risk of forest and peat fires increases.

According to generalized data for weather stations in Belarus, the frequency of extremely dry periods in the country varies from 3 to 23%, averaging 10%. The highest frequency (once every 4–6 years) is typical for the western part of Grodno and the central part of the Minsk region (Grodno and Minsk – frequency 17%, Volkovysk – 23%). The minimum frequency of occurrence – 3% or once every 33 years – was noted in Zhitkovichi and Gorki.

Dust storms black storms, transfer of large amounts of dust or sand by strong winds. They are usually found in deserts, semi-deserts, and plowed steppes. Severe dust storms also occur due to irrational cultivation of the land. They cause great damage to agriculture, cover crops, and destroy the surface layer of soil over large areas. Dust from the southern regions of Eastern Europe, the Mediterranean, and even the Sahara is occasionally brought into Belarus. On light mineral soils, at wind speeds above 5−6 m/s, and on peat soils above 8–9 m/s, wind erosion of the soil is observed. In the south of the republic in April - June, conditions are created for the occurrence of dust storms in dry weather, absence or weak development of vegetation in the fields and winds stronger than 15 m/s. There have been cases of wind removal of up to 40 tons of dry peat from 1 hectare and removal of soil from mineral areas 2-3 times more. Dust storms are prevented by planting shelterbelts, regulating snowmelt, retaining melt water, bilaterally regulating the soil water regime and other anti-erosion measures.