Hail is a very serious natural disaster, causing colossal damage every year agriculture. Hail is actually chunks of ice falling from the sky. It is not uncommon for ice floes to reach the size of an egg or even an apple.
Grain harvest, vineyards, orchards can be done in 15 minutes. die due to air bombing large hail. According to the High Mountain Geophysical Institute, just one hailstorm on August 19, 2015 caused about 6 billion rubles in damage to the economy of the North Caucasus.
In the Middle Ages, to prevent the formation of large hailstones, people rang bells and fired cannons in an attempt to sound waves cause an ominous cloud to spill onto the Earth before the hailstones in it reach large sizes. Now they are using modern and more reliable methods of implementation in thunder cloud- launch anti-hail pyrotechnic shells and rockets.
So what is hail, how is it formed, and what determines the size of hailstones? In summer, the air above the Earth's surface warms up greatly, an upward flow is formed, which can be so strong that it can carry steam to a height of 2.5 km, where the temperature is much below zero, as a result of which water droplets become supercooled, and if they rise even higher (by height of 5 km), ice hailstones begin to form. In the future, hailstones can grow to significant sizes due to the freezing of supercooled drops colliding with them, as well as the freezing of hailstones among themselves.
It is important to note that large hailstones can only appear if there are strong updrafts in the clouds that can keep them from falling to the ground for a long time. When the updraft speed in the cloud is less than 40 km/h, for a long time hailstones will not be held in the cloud - and they fall down quite quickly, without having time to grow, and if they fall from a relatively small height, they can melt, as a result of which showers fall on the ground. The thicker the cloud, the greater the likelihood that hailstones will grow to large sizes and large pieces of ice will fall to the Earth.
The clouds from which hail falls are characterized by a dark gray, ashy color and white, as if tattered, tops. Each cloud consists of several clouds piled on top of each other: the lower one is usually located at a small height above the ground, while the upper one is at an altitude of 5, 6 and even more thousand meters above the earth’s surface. Sometimes the lower cloud stretches out in the form of a funnel, as is typical for the phenomenon of tornadoes. Hail is usually accompanied by a thunderstorm and occurs in thunderstorm whirlwinds (tornadoes, tornadoes) with a strong upward air current. Phenomena such as a tornado, tornado and hail are closely related to each other and to cyclonic activity. Hail storms are sometimes unusually strong.
Most often, hail falls in temperate latitudes. Moreover, it occurs much less frequently over expanses of water (upward air currents occur more often over the earth’s surface than over the sea).
Hail that falls in mountainous areas is the largest and most dangerous. This can be explained by the fact that in hot weather The relief of the earth's surface in the mountains warms up unevenly, very powerful upward currents arise, lifting particles of water vapor to a height of up to 10 km, where the air temperature is below -40 ° C. Large hail flying from this height can reach speeds of 160 km/h and lead to crop destruction, serious damage to buildings, transport, and the death of people and animals.
There are many known catastrophic cases of large hail. So, on April 14, 1986 in Bangladesh in the city of Gopalgandezh, kilogram hailstones fell from the sky. The hail killed 92 people. Even heavier pieces of ice bombed the Indian city of Huderabad in 1939. They weighed at least 3.4 kilograms. Judging by the destruction, the largest hailstorm occurred in China in 1902.
And now some facts about hail and measures to combat it in our country.
In Russia, the North Caucasus and the south are most susceptible to natural disasters, in particular heavy hail. On average in the North Caucasus for the entire summer season hail causes damage in areas of about 300-400 thousand hectares, of which the crop is completely destroyed on an area of 142 thousand hectares.
IN last decades in connection with global warming climate the frequency and intensity of natural phenomena is increasing in Russia by 6-7% per year; accordingly, losses from natural Disasters. More than 500 cases are recorded in the country every year. emergency situations, including hail and drought, and tornadoes became more frequent.
In 2016, hail dealt its first significant blow to North Caucasus in May-June. According to the Main Directorate of the Ministry of Emergency Situations, as a result of the disaster in the Stavropol region, damage was caused to more than 900 private households, 70.1 thousand hectares of crops were damaged by hail, of which 17.8 thousand hectares were destroyed. IN North Ossetia hail the size of egg, which took place on June 5, destroyed 369.8 hectares of potato crops, corn for grain, barley, the amount of damage is estimated at 27 million rubles.
One of the methods of protection against large hail is to install protective nets over vegetable and grape plantations, but the nets do not always withstand bombardment by very large and fast hail.
More than fifty years ago, 10 paramilitary hail control services were created in the USSR, including three in the North Caucasus - Krasnodar, North Caucasus and later Stavropol service, which protect an area of 2.65 million hectares in the North Caucasus and South federal districts. According to experts, the protection area needs to be expanded. To create new points of influence, command posts 497 million rubles will be required. and for their maintenance annually - about 150 million rubles. However, according to scientists, protection from hail will provide economic effect about 1.7 billion rubles.
Anti-hail rockets spray a reagent into areas of new growth of hail and hail clouds, which leads to accelerated precipitation and rainfall instead of hail. At the end of the 1950s, the first anti-hail projectile, Elbrus-2, fired from anti-aircraft gun KS-19. Since then, shells and installations have been improved. The most recent development of 2014 is the small-sized anti-hail complex "As-Eliya" consisting of an "As" missile and a 36-barreled automated rocket launcher"Eliya-2" with wireless remote control.
hail in different countries Oh
According to meteorological observations, the most big hail, which once fell on the ground, was in April 1981 in Guangdong Province, China. Hailstones weighing 7 kilograms were found there. Hail is usually small in size, with a diameter of about 4.5 centimeters. As a result of the severe natural disaster, 5 people were killed and about 10,500 buildings were destroyed.
In addition, here is some more information about large hail found in various sources:
The hailstones that fell in Huderabad (India) in 1939 weighed about a kilogram. The weight of individual hailstones reached 3.4 kilograms!
Large hail also occurred in Coffeeville, Kansas on September 3, 1970. The diameter of the hailstones was more than 14.2 centimeters, and the circumference was about 44.45 centimeters. The hailstones weighed up to 755 grams.
During the tornado in Kansas, USA on May 30, 1879, hailstones up to 38 cm in diameter were observed. After their fall, holes formed in the ground, measuring 17 by 20 centimeters.
Facts about the city
Although this is not the limit. Based on the effects of hail, the destruction left by it, the world's largest hail fell in 1902 in China.
Often, hail falls to the ground with something inside it. This happens because inside the cloud that generated the hail, the ascending and descending currents are very strong. The object inside does not fall back to the ground, but moves up and down inside the cloud, comes into contact with supercooled drops and becomes a center of condensation, turning into large hail. For example, in Bovina (USA) in 1894, a hailstone fell, inside which a turtle 20 centimeters long was trapped.
Elena Pokidaeva, Samogo.Net
Back in the Middle Ages, people noticed that after loud sound rain and hail either do not fall at all, or hailstones fall to the ground much smaller than usual. Not knowing why and how hail forms, in order to avoid disaster, to save crops, at the slightest suspicion of the possibility of huge ice balls, they rang bells, and if possible, even fired cannons.
Hail is a type of rainfall that forms in large cumulonimbus clouds that are ashy or dark gray in color with white ragged tops. After this, it falls to the ground in the form of small spherical or irregular shape particles from not clear ice.
The size of such ice floes may well vary from a few millimeters to several centimeters (for example, the size of the largest peas that were recorded by scientists was 130 mm, and their weight turned out to be about 1 kg).
This precipitation is quite dangerous: studies have shown that every year about 1% of the vegetation on Earth is killed by hail, and the damage they cause to the economies of different countries of the world is about $1 billion. They also cause trouble for residents of the region where the hail has occurred: large hailstones are quite capable of destroying not only crops, but also breaking through the roof of a car, the roof of a house, and in some cases, even killing a person.
How is it formed?
Precipitation of this type occurs mainly in hot weather, during the day, and is accompanied by lightning, thunder, downpours, and is also closely associated with tornadoes and tornadoes. This phenomenon can be observed either before or during rain, but almost never after. Despite the fact that such weather lasts relatively short time (on average about 5-10 minutes), the layer of precipitation that falls on the ground can sometimes be several centimeters.
Each cloud that carries summer hail consists of several clouds: the lower one is located low above the surface of the earth (and can sometimes stretch out in the form of a funnel), the upper one is at an altitude significantly exceeding five kilometers.
When the weather is hot outside, the air heats up extremely strongly and, together with the water vapor contained in it, rises, gradually cooling. At a great height, the steam condenses and forms a cloud that contains drops of water, which may well fall onto the earth's surface in the form of rain.
Due to the incredible heat, the updraft can be so strong that it can carry steam to a height of 2.4 km, where temperatures are much below zero, as a result of which water droplets become supercooled, and if they rise higher (at an altitude of 5 km) they begin to form hailstones (At the same time, it usually takes about a million tiny supercooled drops to form one such piece of ice).
For hail to form, the speed must be air flow exceeded 10 m/s, and the air temperature was not lower than -20°, -25°C.
Together with water drops they rise into the air tiny particles sand, salt, bacteria, etc., on which frozen steam sticks and causes hail. Once formed, the ice ball is quite capable of rising several times on the updraft to the upper layers of the atmosphere and falling back into the cloud.
If an ice pellet is cut into pieces, it can be seen to consist of layers of transparent ice alternating with translucent layers, thus resembling an onion. To determine exactly how many times it rose and fell in the middle of a cumulonimbus cloud, you just need to count the number of rings;
The longer such a hailstone flies through the air, the larger it becomes, collecting not only droplets of water, but in some cases even snowflakes along the way. Thus, a hailstone with a diameter of about 10 cm and a weight of almost half a kilogram may well form.
The higher the speed of the air currents, the longer the ice ball flies through the cloud and the larger it becomes.
A hailstone flies across a cloud as long as the air currents are able to hold it. After the piece of ice gains a certain weight, it begins to fall. For example, if the speed of the upward flow in a cloud is about 40 km/h, it is not able to hold hailstones for a long time - and they fall down quite quickly.
The answer to the question why ice balls formed in a small cumulonimbus cloud do not always reach earth's surface, is simple: if they fall from a relatively small height, they have time to melt, as a result of which showers fall on the ground. The thicker the cloud, the greater the likelihood that it will fall icy precipitation. Therefore, if the cloud thickness is:
- 12 km – the probability of occurrence of this type of precipitation is 50%;
- 14 km – chances of hail – 75%;
- 18 km – heavy hail will definitely fall.
Where is ice precipitation most likely to be seen?
This kind of weather can't be seen everywhere. For example, in tropical countries and polar latitudes this is quite a rare event, and icy precipitation falls mainly either in the mountains or on high plateaus. There are lowlands here where hail can be observed quite often. For example, in Senegal it not only often falls out, but also often a layer icy precipitation is several centimeters.
The regions suffer quite greatly from this natural phenomenon. North India(especially during the summer monsoons), where, according to statistics, every fourth hailstone is larger than 2.5 cm.
The largest hail was recorded here by scientists in late XIX century: the ice peas were so huge that they beat 250 people to death.
Most often, hail falls in temperate latitudes - why this happens largely depends on the sea. Moreover, if it occurs much less frequently over expanses of water (upward air currents occur more often over the earth’s surface than over the sea), then hail and rain fall much more often close to the shore than far from it.
Unlike tropical latitudes, in temperate latitudes there is much more ice precipitation in the lowlands than in mountainous area, and on a more uneven earth’s surface they can be seen more often.
If hail does fall in mountainous or foothill areas, it turns out to be dangerous, and the hailstones themselves are extremely large in size. Why is that? This happens primarily because in hot weather the relief here warms up unevenly, very powerful upward currents arise, raising steam to a height of up to 10 km (it is there that the air temperature can reach -40 degrees and is the cause of the largest hail flying to the ground from speed of 160 km/h and bringing with it trouble).
What to do if you find yourself under heavy precipitation
If you are in a car when the weather turns bad and hail falls, then you need to stop the car near the side of the road, but without driving off the road, since the ground may simply wash away and you will not get out. If possible, it is advisable to hide it under a bridge, put it in a garage or covered parking lot.
If it is not possible to protect your car from precipitation during such weather, you need to move away from the windows (or better yet, turn your back to them) and cover your eyes with your hands or clothes. If the car is large enough and its dimensions allow, you can even lie on the floor.
It’s absolutely forbidden to leave the car when it’s raining and hailing! Moreover, you won’t have to wait long, since this phenomenon rarely lasts longer than 15 minutes. If you are indoors during a rainstorm, you need to move away from the windows and turn off electrical appliances, since this phenomenon is usually accompanied by a thunderstorm with lightning.
If such weather finds you outside, you need to find shelter, but if there is none, you definitely need to protect your head from falling enormous speed hailstones It is advisable not to hide under trees during such a downpour, since large hailstones can break branches, which can seriously injure you if they fall.
Interesting facts about the city
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Did you know that:
- Every year, up to 1% of the total vegetation suffers as a result of hailstorms globe, and the damage caused by hail to the economies of different countries totals about $1 billion;
- Hailstones can take various shapes: spherical, cone-shaped, apple-shaped, elliptical, etc.;
- Milky-white hailstones can contain various kinds of “surprises” in the form of plant pollen, bacteria, insects and even frogs and small fish. Microscopic objects enter the hail cloud as a result of rising air currents (in cumulonimbus hail clouds these can be very strong) in the area over which the cloud developed. Heavier objects fall into the hail cloud thanks to powerful mesoscale vortices - tornadoes, tornadoes. The ascending and descending currents in such powerful cumulonimbus (usually super-cell) clouds are so strong that an object comparable in mass to a frog or fish does not fall out of the cloud back to the ground, but, obeying the air currents, moves upward in the cloud - down; comes into contact with supercooled drops and becomes a condensation nucleus, turning into a full-fledged hailstone...
- Regions of Northern India suffer the most from large hail, where one in four hailstones that reach the ground exceeds 2.5 cm in size. With the approach of the summer monsoons, the danger of large hail in this country increases sharply. But perhaps the most destructive hailstorm occurred in India in 1888, when large hailstones killed 250 people.
- In the USA, the largest hail was recorded on September 3, 1970 in the town of Coffeyville (Kansas). The size of individual hailstones was then more than 14 cm, while their weight reached almost a kilogram. But this is far from a world record!
- The kilogram hailstones were those that fell on April 14, 1986 in Bangladesh, but the heaviest ice blocks fell during a hailstorm in Huderabad (India) in 1939. Then their weight reached 3.4 kg. But the largest hail, judging by the destruction, fell in 1902 in China.
- As you know, a hailstone in cross-section resembles an onion, i.e. consists of rings. In order to find out how many times a hailstone has traveled up/down inside a cumulonimbus cloud, you simply need to count the number of such rings.
- Hail rarely falls for more than 15 minutes. The average duration of hail is about 6 minutes.
- Fall speed large hailstones can reach 160 km/h.
How to behave during a major hail storm?
If you are in a car, then stay away from the windows, it is advisable to turn your back to them (facing the center of the cabin) and cover your eyes with your hands or clothes. If you have small children with you, then you need to cover them with your body and also cover your eyes either with clothes or with your hand. It is best to lie on the floor (if the interior dimensions allow).
- If you are driving a car, stop driving. However, first look around (if visibility allows) to see if there is any shelter nearby (bridges, overpasses, garages, covered parking lots). If there is no suitable cover nearby, make sure you are not in the middle of the roadway and, if possible, stay close to the edge of it. However, it should be borne in mind that going to the side of the road (especially in lowlands) is dangerous, because it can be washed away during intense precipitation and possible flooding. Also, do not drive into areas where hailstones accumulate, as your car may also lose control. Never leave your car during a hail storm! remember, that average duration hail lasts approximately 6 minutes, and very rarely lasts longer than 15 minutes.
- If hail catches you indoors, then stay as far away from windows as possible and do not leave the house. Do not use electrical appliances, because Hail is usually accompanied by thunderstorm activity.
- If hail catches you on the street, then try to choose a shelter. Otherwise, protect your head from hail strikes. Do not go into low areas, which can fill with water in a matter of minutes and turn into a rapid stream, or in places with the greatest accumulation of hailstones, where their layer is clearly thicker than around it.
- Do not try to find shelter under trees, because... There is a high risk of not only being struck by lightning, but also that large hailstones can break tree branches, which can cause additional damage to you.
If you or someone nearby has been affected by large hailstones. Be sure to contact the rescue service and indicate the approximate size of the hailstones.
Hail is one of the most unpleasant natural phenomena. Of course, according to destructive force It cannot be compared with a tsunami or earthquake, but hail can also cause enormous damage.
Every year, hail damages crops, damages buildings, cars, property, and even kills animals.
People have always sought to explain the nature of hail, predict its fall, and reduce the damage caused. Despite the fact that modern meteorology has explained how hail appears and has learned to predict its occurrence in a particular region with great accuracy, hail still plagues people.
Hail: what is it?
Hail is a type of rainfall that occurs in rain clouds. Ice floes can form in the form of round balls or have jagged edges. Most often these are peas white, dense and opaque. Hail clouds themselves are characterized by a dark gray or ashy hue with jagged white ends. The percentage probability of a fall depends on the size of the cloud. solid precipitation. With a thickness of 12 km, it is approximately 50%, but when it reaches 18 km, there will definitely be hail.
The size of the ice floes is unpredictable - some can look like small snowballs, while others reach several centimeters in width. The largest hail was seen in Kansas, when “peas” up to 14 cm in diameter and weighing up to 1 kg fell from the sky!
Precipitation in the form of rain may accompany hail, in in rare cases- snow. There are also loud rumbles of thunder and flashes of lightning. In susceptible regions, large hail may occur in conjunction with a tornado or waterspout.
When and how does hail occur?
Most often, hail forms in hot weather during the daytime, but in theory it can occur down to -25 degrees. It can be noticed during rain or immediately before other precipitation falls. After a rainstorm or snowfall, hail occurs extremely rarely, and such cases are the exception rather than the rule. The duration of such precipitation is short - it usually ends in 5-15 minutes, after which you can observe good weather and even bright sunshine. However, the layer of ice that falls in this short period of time can reach several centimeters in thickness.
Cumulus clouds, in which hail forms, consist of several individual clouds located on different heights. So the top ones are more than five kilometers above the ground, while others “hang” quite low and can be seen with the naked eye. Sometimes such clouds resemble funnels.
The danger of hail is that not only water gets inside the ice, but also small particles of sand, debris, salt, various bacteria and microorganisms that are light enough to rise into the cloud. They are held together by frozen steam and turn into large balls that can reach record sizes. Such hailstones sometimes rise into the atmosphere several times and fall back into the cloud, collecting more and more “components.”
To understand how hail forms, just look at a cross-section of one of the fallen hailstones. Its structure resembles an onion, in which transparent ice alternates with translucent layers. Secondly, there is various “garbage”. Out of curiosity, you can count the number of such rings - this is how many times the piece of ice rose and fell, migrating between the upper layers of the atmosphere and the rain cloud.
Causes of hail
In hot weather, hot air rises, carrying with it particles of moisture that evaporate from bodies of water. During the rise, they gradually cool, and when they reach a certain height, they turn into condensate. From it clouds are formed, which soon become rain or even a real downpour. So if there is such a simple and understandable water cycle in nature, then why does hail happen?
Hail occurs because on particularly hot days, currents of hot air rise to record heights, where temperatures drop well below zero. Supercooled droplets that cross a threshold of 5 km turn into ice, which then falls in the form of precipitation. Moreover, even to form a small pea, more than a million microscopic particles of moisture are needed, and the speed of air flows must exceed 10 m/s. They are the ones who hold the hailstone inside the cloud for a long time.
As soon as air masses are not able to withstand the weight of the formed ice, hailstones fall down from a height. However, not all of them will reach the ground. Small pieces of ice will melt along the road and fall as rain. Since quite a few factors need to coincide, a natural phenomenon Hail is quite rare and only in certain regions.
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