It is unlikely that the inhabitants of the region where the largest hailstorm in the world took place were satisfied with such glory of their land. Hail is one of the most dangerous. It manifests itself in heavy pieces of ice falling from the sky, usually having a round shape. Hail destroys crops, destroys infrastructure and can even kill people and animals.
Where and when did the largest hail fall?
Top 1. South Dakota, 2010
According to modern weather observations, the most big hail fell on July 23, 2010. The setting was the town of Vivien in South Dakota (USA). Thunderstorms moved through the central part of the state during the afternoon and early evening hours. A particularly severe thunderstorm moved south through Stanley, Jones and Lyman counties.
According to meteorologists, the town of Vivienne was particularly affected, where hail, tornadoes and gale force winds were reported. The diameter of the hailstones that fell was about 47 centimeters, and their weight was about 900 grams.
The surviving hailstone of record diameter was discovered by a town resident named Lee Scott. An ice stone falling from the sky managed to create an impact hole with a diameter of 25 centimeters. National meteorological service did not arrive at the place immediately. And by the time they were able to measure the remaining precipitation, the hailstone had already decreased in size due to melting.
For a long time largest hail in history (among those recorded) was considered to have fallen in the summer of 2003 in American state Nebraska. A thunderstorm passed through the southern part of the state in June. Measurements of the surviving hailstones showed that their diameter was about 18 centimeters. At the same time, the hailstone’s circumference was 47 centimeters, which is larger than that of the sample that fell seven years later on Dakota. The impact pit at the site of the hailstone impact was 36 centimeters in diameter, which also exceeds the result found in Dakota.
A hailstone of record size was discovered by climate service staff on June 22 near the town of Aurora. Jay Lawrington, a service employee, noted that if local residents did not select the hailstone and did not provide it with a suitable temperature regime Before the scientists arrived, they would not have known about the record. He also noted that a piece of ice stone fell into gutter and lost 40% of my weight.
The hailstone was delivered to National Center Atmospheric Research in Boulder, Colorado, where it is to be stored in perpetuity.
Hail struck Coffeyville on September 3, 1970. According to researchers, the diameter of the largest hailstone was 14 centimeters and its weight reached 700 grams.
Although the largest hailstones in diameter and circumference have hit the United States over the past hundred years, many countries have their own (albeit less impressive) records:
- Canada. On July 31, 1987, the Edmonton tornado hit Alberta. After it, a hailstone with a diameter of 7.8 centimeters was discovered.
- Australia. On April 14, 1999, a terrible hailstorm hit Sydney. The largest hailstones reached a size of 9.5. centimeters. The storm damaged 20 thousand buildings, 40 thousand cars and 25 aircraft at the airport. Lightning killed one fisherman and injured several others. Damage from the hail amounted to one and a half billion US dollars.
- Germany. A series of large hailstorms hit the states of Baden-Württemberg and Lower Saxony. A hailstone with a diameter of 14 centimeters was discovered near the Württemberg city of Reutlingen.
The first killer city recorded in history probably dates back to the 9th century AD. Several dozen skeletons of people who died in the 9th century were discovered near Lake Roopkund in the Himalayas. It is believed that these were settlers looking for a new place to live. One of the versions of their death is a strong hail.
The heaviest hailstorm on record hit the Gopalganji district of Bangladesh on April 14, 1986. When measured, the surviving samples showed a weight of one kilogram. Rainfall in Bangladesh led to casualties - 92 people died.
The largest hail accumulation on earth was recorded in 1959 in Kansas. On June 3, the Seldon area experienced a prolonged hailstorm, after which an area of up to 140 square kilometers was littered with precipitation up to 45 centimeters high.
The deadliest hailstorm on record occurred in India. In 1888 natural disaster hit the Morabahad and Beheri districts. According to eyewitnesses, hailstones the size of oranges fell from the sky. The hailstorm resulted in the death of 246 people and 1,600 sheep and goats. IN late XIX century, there was no hail warning system yet, which led to so many casualties.
These are not the only examples of deadly rainfall in the world. In 1979, there was a hail storm in Fort Collins, Colorado, during which ice blocks the size of grapefruits fell from the sky. They damaged 2,000 houses and 2,500 cars. Twenty-five people were injured (mostly from hailstones to the head), and Small child died of a fractured skull while his mother sought shelter from nature's wrath.
Although the world's largest hailstone caused the most destruction, it left its mark on the face of South Dakota. Today the warning system works more effectively emergency situations, which helps prevent human casualties. But modern villages and cities are still vulnerable to falling from the sky ice blocks, which damage houses and gardens.
Very often in the summer it is observed unusual look precipitation in the form of small and sometimes large pieces of ice. Their shape can be different: from small grains to large hailstones the size of a chicken egg. Such hail can cause catastrophic consequences - roost material damage and harm to health, as well as damage to agriculture. But where and how does hail form? There is a scientific explanation for this.
Hail formation is facilitated by strong updrafts of air within a large cumulus cloud. This kind atmospheric precipitation consists of pieces of ice different sizes. The structure of a hailstone can consist of several alternating layers of ice - transparent and translucent.
How do ice floes form?
Hail formation - complex atmospheric process, based on the water cycle in nature. Warm air, which contains moisture vapor, rises upward on a hot summer day. As the altitude increases, these vapors cool and the water condenses, forming a cloud. It, in turn, becomes a source of rain. But it also happens that during the day it is too hot, and the rising air flow is so strong that drops of water rise to a very high altitude, bypassing the region of the zero isotherm, and become supercooled. In this state, droplets can occur even at temperatures of -400C at an altitude of more than 8 kilometers.
Supercooled drops collide in the air flow with tiny particles sand, combustion products, bacteria and dust, which become centers of moisture crystallization. This is how a piece of ice is born - more and more droplets of moisture stick to these small particles and, at an isothermal temperature, turn into real hail. The structure of a hailstone can tell the story of its origin through layers and peculiar rings. Their number indicates how many times the hailstone rose into the upper atmosphere and descended back into the cloud.
What determines the size of hailstones
The speed of updrafts inside cumulus clouds can vary from 80 to 300 km/h. Therefore, newly formed pieces of ice can continuously move, also at high speed, along with air currents. And the greater the speed of their movement, the larger the size of the hailstones. Passing repeatedly through the layers of the atmosphere, where the temperature changes, at first small hailstones become overgrown with new layers of water and dust, sometimes forming hailstones impressive size- with a diameter of 8-10 cm and a weight of up to 500 grams. One raindrop is formed from approximately a million supercooled water particles. Hailstones with a diameter exceeding 50 mm usually form in cellular cumulus clouds, where there are super-powerful updrafts of air. A thunderstorm involving such rain clouds can generate intense wind squalls, heavy downpours and tornadoes.
How to deal with hail?
Over the long history of meteorological observations, people have discovered that hailstones do not form when there are sharp sounds. Therefore, most modern means against hail, which have proven their effectiveness are special anti-aircraft guns. When firing charges from such weapons into black, thick clouds, a strong sound is achieved from their explosion. Flying particles powder charge promote the formation of droplets at a relatively low height. Thus, the moisture contained in the air does not form hail, but falls on the ground as rain. Another popular method of preventing precipitation in the form of hail is artificial spraying of fine dust. This is usually done using airplanes that fly directly over a thundercloud. When microscopic dust particles are sprayed, it creates great amount hail germs. These tiny particles of ice intercept droplets of supercooled water. The essence of the method is that in a thundercloud the reserves of supercooled water are small, and each hail embryo prevents the growth of others. Therefore, hailstones falling on the ground are small in size and do not cause serious damage. There is also a high probability that instead of hail there will be regular rain.
The same principle is used in the third method of preventing hail. Artificial hail nuclei can be created by introducing silver iodide, dry carbon dioxide or lead into the supercooled part of a cumulus cloud. One gram of these substances can create 1012 (trillion) ice crystals.
All these methods of dealing with hail depend on meteorological forecasts. It is important to cover young crops on time, harvest on time, hide valuables and objects, cars. Also, you should not leave it on open area livestock.
These simple measures will help minimize the damage caused by hail. It is better to undertake them immediately, as soon as a hail forecast is transmitted or threatening clouds of a characteristic appearance appear on the horizon.
I only know when it happens
WHY DOES HAIL HAPPEN?
Hail is pieces of ice (usually irregular shape) that fall from the atmosphere with or without rain (dry hail). Hail falls primarily in summer from very powerful cumulonimbus clouds and is usually accompanied by thunderstorms. IN hot weather hailstones can reach the size of a pigeon and even chicken egg.
The strongest hailstorms have been known since ancient times from chronicles. It happened that not only individual areas, but even entire countries were subject to hail damage. Such phenomena still happen today.
On June 29, 1904, large hail fell in Moscow. The weight of hailstones reached 400 g or more. They had a layered structure (like an onion) and external spines. The hail fell vertically and with such force that the glass of greenhouses and conservatories seemed to be shot through with cannonballs: the edges of the holes formed in the glass turned out to be completely smooth, without cracks. Hailstones made holes up to 6 cm in the soil.
On May 11, 1929, heavy hail fell in India. There were hailstones 13 cm in diameter and weighing a kilogram! This is the largest hail ever recorded by meteorology. On the ground, hailstones can freeze into large pieces, which explains the amazing stories about the size of hailstones the size of a horse's head.
The history of the hailstone is reflected in its structure. In a round hailstone cut in half, you can see the alternation of transparent layers with opaque ones. The degree of transparency depends on the speed of freezing: the faster it goes, the less transparent the ice. In the very center of a hailstone, the core is always visible: it looks like a grain of “cereal” that often falls in winter.
The rate at which hailstones freeze depends on the water temperature. Water usually freezes at 0°, but in the atmosphere the situation is different. In the ocean of air, raindrops can remain in a supercooled state at very low temperatures: minus 15-20° and below. But as soon as a supercooled drop collides with an ice crystal, it instantly freezes. This is already the embryo of a future hailstone. It occurs at altitudes of more than 5 km, where even in summer the temperature is below zero. Further growth of hailstones occurs under different conditions. The temperature of a hailstone falling under the influence of its own gravity from the high layers of the cloud is lower than the temperature of the surrounding air, so droplets of water and water vapor from which the cloud consists are deposited on the hailstone. The hailstone will begin to get larger. But for now it is small, and even a moderate rising air flow picks it up and carries it to the upper parts of the cloud, where it is colder. There it cools and when the wind weakens it begins to fall again. The speed of the upward flow either increases or decreases. Therefore, a hailstone, having made a “journey” several times up and down into powerful clouds, can grow to significant sizes. When it becomes so heavy that the updraft can no longer support it, the hailstone will fall to the ground. Sometimes “dry” hail (without rain) falls from the edge of a cloud, where the updrafts have weakened significantly.
So, for the formation of large hail, very strong upward air currents are needed. To maintain a hailstone with a diameter of 1 cm in the air, a vertical flow with a speed of 10 m/sec is required, for a hailstone with a diameter of 5 cm - 20 m/sec, etc. Such stormy flows were discovered in hail clouds by our pilots. More high speeds- hurricanes - recorded by movie cameras that filmed the growing cloud tops from the ground.
Scientists have long tried to find means to disperse hail clouds. In the last century, cannons were built to shoot at clouds. They threw out a swirling smoke ring into the heights. It was assumed that vortex movements in the ring could prevent the formation of hail in the cloud. It turned out, however, that, despite the frequent shooting, hail continued to fall from the hail cloud with the same force, since the energy of the vortex rings was negligible. Nowadays, this problem has been fundamentally solved, and mainly through the efforts of Russian scientists.
Hail is one of the most unusual and mysterious atmospheric phenomena. The nature of its occurrence is not fully understood and remains the subject of fierce scientific debate. Does it hail at night - the answer to this question is of interest to everyone who has never experienced it a rare event in the dark.
Brief information about the city
Hail is atmospheric precipitation in the form of pieces of ice. The shape and size of these deposits can vary greatly:
- Diameter from 0.5 to 15 cm;
- Weight from several grams to half a kilogram;
- The composition can also be very different: several layers clear ice, and alternating transparent and opaque layers;
- The form is very diverse - up to bizarre formations in the form of “flower buds”, etc.
Hailstones easily stick together, forming large particles the size of a fist. Precipitation of more than 2 cm in diameter is already sufficient to cause major damage to a farm. As soon as hail of this size is expected, a storm warning is issued.
Different states may have different size thresholds: it all depends on the specific agricultural area. For example, for grape plantations, even small hailstones will be enough to destroy the entire crop.
The necessary conditions
According to modern ideas about the nature of hail, for its occurrence it is necessary:
- Water drops;
- Condensation yard;
- Rising air currents;
- Low temperature.
Similar atmospheric phenomenon is formed in 99% of cases in temperate latitudes over large continental spaces. Most researchers believe that thunderstorm activity is a prerequisite.
In tropical and equatorial zones Hail is a fairly rare occurrence, despite the fact that thunderstorms occur quite often there. This happens because for the formation of ice, it is also necessary that at an altitude of approximately 11 km there is enough low temperature, which does not always happen in warm places globe. Hail occurs there only in mountainous areas.
In addition, the probability of hail becomes vanishingly small as soon as the air temperature drops below -30 °C. Supercooled water droplets in this case are located near and inside snow clouds.
How does hail occur?
The mechanism of formation of this type of precipitation can be described as follows:
- An ascending air flow containing a significant number of water droplets encounters a cloud layer of low temperature on its path. It often happens that such an air flow is a strong tornado. A significant part of the cloud should be below the freezing point (0 ° C). The probability of hail formation increases a hundredfold when the air temperature at an altitude of 10 km is about -13 °.
- Upon contact with condensation nuclei, pieces of ice are formed. As a result of alternating processes of raising and lowering, hailstones acquire a layered structure (transparent and white levels). If the wind blows in a direction where there are a lot of water droplets, a transparent layer is created. If water vapor blows into an area, the hailstones become covered with a crust of white ice.
- When colliding with each other, the ice can stick together and seriously grow in size, forming irregular shapes.
- Hail formation may last for at least half an hour. As soon as the wind stops supporting the increasingly heavy thunder cloud, hail will begin to fall on the earth's surface.
- After the ice passes past the area with temperatures above 0 ° C, the slow process of melting begins.
Why doesn't there hail at night?
In order for ice particles of such a size to form in the sky that they do not have time to melt when they fall to the ground, sufficiently strong vertical air currents are needed. In turn, for the upward flow to be powerful enough, strong heating is required earth's surface. That is why, in the vast majority of cases, hail falls in the evening and afternoon hours.
However, nothing prevents it from falling out at night, if there is a thundercloud of sufficient size in the sky. True, at night most people sleep, and small hail may go completely unnoticed. That's why the illusion is created that “freezing rain” only occurs during the day.
As for statistics, in most cases hail occurs in summer time at approximately 15:00. The possibility of precipitation is quite high until 22:00, after which the probability of this type of precipitation tends to zero.
Observational data from meteorologists
Among the most known cases“Icy rain” in the dark:
- One of the most powerful overnight hailstorms occurred on June 26, 1998 in the Illinois village of Hazel Crest. Then local Agriculture seriously damaged by hailstones measuring 5 cm in diameter that fell around 4 a.m.;
- On September 5, 2016, hail fell in the vicinity of Yekaterinburg, damaging local crops;
- In the Belarusian city of Dobrush on the night of August 26, 2016, ice floes the size of fists broke car windows;
- On the night of September 9, 2007, there was hail in the Stavropol region, which damaged 15 thousand private houses;
- On the night of July 1, 1991, Mineral water An icy downpour struck, not only causing damage to local households, but even damaging 18 aircraft. The average size ice was about 2.5 cm, but there were also giant balls the size of a chicken egg.
Many people still don't know if it hails at night. Probability of occurrence this phenomenon at night it is vanishingly small, but still there. And for these rare cases There are many strong anomalies that cause serious harm to the economy.
They should be distinguished from frost and dew, which are nothing more than condensed moisture,
settled on objects or plants. The phenomenon of fog also occurs due to temperature differences. For example, in the fall it comes from warmer bodies of water. Steam, once in cold air, immediately condenses. But the water suspension, due to its own gravity, cannot rise up and become a cloud, and therefore spreads close to the ground, filling the lowlands and floodplains of rivers. However, here we will talk specifically about precipitation. How does hail differ from similar grains? Find out in this article.
Transitional state?
Even a primary school student will tell you what hail is: something between rain and snow. Droplets of water freeze and turn into pieces of ice - small and large. Falling to the ground, they make a loud noise, as if nuts or pebbles are falling. Hailstones do not melt immediately. Sometimes you can observe how they cover the ground with a carpet several tens of centimeters high. But the icy rain, although it hurts your face, immediately turns into water. Sometimes you can hear the crystal ringing of individual “drops” on the asphalt. But more often this is accompanied by the sounds of regular rain. And the snow grains fall to the ground with a quiet rustle. These sediments also differ in appearance. Hailstones are large and translucent. freezing rain looks like shards of glass. And the grains can be likened to miniature snowballs.
How is snow formed?
To seriously understand the question of what hail is, you simply need to return to the basics of natural history and remember how clouds carrying rain or snow are formed. Moisture evaporates from the surface of the earth. But most often clouds form over seas-oceans, where there is more water. air lifts this vapor upward. On different heights Due to the decrease in air temperature, moisture condenses. But it does not turn into droplets of water, but turns into ice crystals, bypassing the liquid state. If the cloud is small and light, the wind drives it to drier areas, where it melts without giving the earth any precipitation. Dense cannot contain heavy, low-floating clouds. Ice crystals begin to fall. If the air temperature at the surface of the earth is above zero, they melt, turning into raindrops. Well, if it’s below zero outside the window, the crystals grow together, forming snowflakes of a wide variety of shapes and sizes.
This is a completely different type of precipitation. And it appears in completely different clouds. Maybe you remember what clouds threaten us with rain? Dense, dark gray, sometimes even purple... Tall, like swirling towers, they fly in quickly, like a tornado. Unlike rainfall, hailstorms are rarely accompanied by lightning and thunder. But there is always a gusty wind. A hailstone is born in the same way as a snowflake - from an ice crystal. But it is not formed at all in flat clouds that carry snow. Hail is generated by the very shape of the clouds. The tall bulk rises several kilometers into the air. It is clear that there is a temperature difference between the lower and upper edges of such a cloud. The crystals located closer to the ground melt, turning into drops of water (hail never falls in winter). But instead of raining down, powerful updrafts push this moisture upward, where it freezes - this time in the form of a small ice ball. If the wind movement inside the cloud is weak, small hail falls. But if air flow strong, then the melted ball is again brought up, where it is overgrown with another ice shell. Sometimes hailstones collide and grow together. Then their shape changes. This is no longer a ball, but a complex conical or pyramidal formation. The more the drop migrates, the larger the hail. Maximum size ice pieces were 150 mm and weighed more than a kilogram.
How to prevent hail
It is clear that falling to the ground at a speed of 150 kilometers per hour, serious injuries and damage can be caused to even smaller specimens. People have long thought about how to prevent the death of crops and livestock from hail. In the Middle Ages, they discovered a pattern: if you make very loud and sharp sounds, then rain will pour out of the clouds. Therefore, when danger approached, people rang a bell or fired a cannon. Due to the pulsation of the air, the hailstones disintegrated, became smaller and melted before reaching the ground. Nowadays a special projectile containing a silver or lead iodide reagent is shot at a dangerous cloud.
Now that we have learned what hail is, let's figure out what snow pellets are. These are small snow balls, 1-2 mm in diameter. Unlike hail, they are fragile, opaque, white. Essentially, these are fused and compacted snowflakes.
For general development
In modern Russian, the word “grad” has another meaning. This is the name of the jet system volley fire, which replaced the outdated Katyusha. This lethal weapon was developed by A.I. Ganichev and the design bureau of the State Research and Production Enterprise "Splav". Basic complex modified from year to year, giving rise to “Grad-V”, “P”, “1A” and other installations.
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