Climatologists, having analyzed meteorological data for half a century, noted a noticeable increase in the risk of tornadoes and squalls. This is especially true of the middle zone, the Black Sea coast, the south of the Far East. How these extremely dangerous atmospheric phenomena are formed and can they be predicted.
Dangerous trend
On the afternoon of June 12, 2012, a tornado passed in Khanty-Mansiysk. For high latitudes, this is a great rarity, but here this has never happened at all. The statistics speaks for itself: from 1844 to 1986 on the territory of the former USSR, out of 248 tornadoes, only eight occurred above the 60th parallel.
The Khanty-Mansiysk tornado was preceded by an abrupt change from record-breaking warm weather to arctic cold and very high humidity. A thundercloud arose, a downpour passed.
"Is this an exception or a symptom?" - asked the climatologists. The answer was a tornado forecasting model that takes into account global warming of the atmosphere, increased humidity, and many other factors. If they continue to intensify in the 21st century, there will be more and more tornadoes.
“We predict an increase in the risk not only of tornadoes, but of dangerous convective phenomena in general, including showers, hails, squalls. This is due to an increase in air temperature and humidity. The wind turn is also important for the tornado. The strongest tornadoes arise near the cold front, because a supercellular cloud is formed there, the air swirls and a funnel is formed, - one of the authors of the model Alexander Chernokulsky, Ph. D. them. A. M. Obukhova.
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Recorded more often
Tornadoes were usually observed in central Russia, up to the Urals, but now they are possible over a much larger area, including Siberia and the north of the European part. In the risk zone is the south of the Far East, as well as the waters of the Black and Caspian Seas, the water surface of which has warmed by two degrees over the past thirty years. According to the most pessimistic scenario proposed by the model, on the Black Sea every second summer day will be favorable for tornadoes. In general, for Russia in the coming decades, the risk of tornadoes will double in comparison with the end of the last century.
However, one should not confuse risk and the event itself - they are two different things.
“Now, due to the significant increase in the number of reports of tornadoes published by eyewitnesses on the Internet, it may seem that the situation has changed for the worse. However, this is primarily due to the increased public interest in hazardous phenomena and publications in general. A real assessment of the climate trends on the planet can be given only after some time after the accumulation of a sufficient amount of information, - comments RIA Novosti Olga Kalmykova, employee of the laboratory of software systems and developments NPO Typhoon (Obninsk).
Blind element
Tornado (other names - thrombus, tornado) is a dense vortex of air rotating at a speed of hundreds of meters per second. It descends from a thundercloud in the form of a trunk and, having reached the ground, begins its destructive movement. The tornado moves at a speed of 70-90 meters per second, sweeping away everything in its path.
Its air walls become impenetrable, and an area of low pressure forms inside, so the funnel also works like a monstrous vacuum cleaner, sucking cars, buildings, animals, people, breaking up the asphalt, emptying reservoirs. An air vortex is able to twist the metal support of the power transmission line, thick tree trunks. Often, a tornado is accompanied by a downpour and large hail, breaking through roofs, killing seedlings in the fields, and livestock. There are cases when hailstones weighing two hundred grams fell from the sky.
Tornadoes do not live long, several minutes or hours. But during this time they pass up to three hundred kilometers, cut down hectares of forest, cause enormous damage to settlements. The diameter of the vortices at the ground can be up to two kilometers.
Sometimes the funnel hangs in the air and retracts back into the cloud, then descends again. From the side it seems that the tornado is jumping.
The strongest tornado outbreak in Europe on record occurred exactly 34 years ago, on June 9, 1984. In the center of Russia, a dozen vortices formed at once, one of which swept along the outskirts of Ivanovo. On the Fujita scale, he was assigned a destructive category - F4. 69 people were killed, fifteen hundred buildings were destroyed. According to the updated data recently presented by Chernokulsky and his colleagues, the width of one of the tornadoes of the outbreak reached 1.74 kilometers, the trail - 85 kilometers.
“Everyone thinks that tornadoes are only in the United States, but they are not uncommon in our country, we just know little about them. For example, analyzing satellite images, we found traces of more than a hundred tornadoes in the forest zone that have occurred over the past 15 years. Some of them were not weaker in characteristics than Ivanovsky! It was lucky that they did not affect settlements,”says the scientist.
Now Chernokulsky and his colleagues are creating a tornado base in Russia and the countries of the former USSR. There are already more than 2,500 entries with the main characteristics of the events that took place. According to the scientist, about a hundred tornadoes form on the territory of the former USSR every year, of which about ten are strong (F2 and higher).
The forecast is more and more relevant
One of the strongest tornadoes in the Moscow region was observed on June 29, 1904. He destroyed 680 houses in the eastern part of the city, wiped out seven villages and several dachas in Lyublino, destroyed 70 hectares of forest there, and 1200 hectares on Losiny Ostrov. The whirlwind crossed the Moskva River, exposing the bottom. There were victims.
According to Chernokulsky and colleagues, since the beginning of the 20th century, about 75 tornadoes have occurred in the Moscow region, of which 14 are strong (categories F2 and higher). The last one that affected Moscow was on July 13, 2016. For such a densely populated region, this is a real disaster. Given that the risk of tornadoes increases, so does the likelihood that they will pass through a populated area.
This means that the forecast becomes especially relevant. If meteorological models determine the threat of a tornado itself well, then prediction of a specific impact site is still causing problems.
“In the United States, where these events occur regularly, claim lives, cause enormous damage, areas that fall into the risk zone are determined in a couple of days. Residents of specific settlements, houses, through which a tornado will pass, are notified literally twenty minutes in advance. People only have time to go down to the basement,”says Chernokulsky.
“Tornado is a dangerous meteorological phenomenon, the nature of the formation of which is still insufficiently studied. For this reason, the currently available forecasting methods, used all over the world, are primarily aimed at forecasting a tornado-hazardous situation,”explains Olga Kalmykova.
NPO Typhoon is testing its own methodology in the Black Sea, since almost half of all water tornadoes in Russia are registered there. For example, in 2014-2015 there were 78 of them. The methodology is based on a comparison of various indices indicating the risk of developing a tornado.
“As our studies have shown, it is the use of the composition of indices, each of which approaches the forecast of tornadoes from one side or another, that gives significantly better results than if these indices were considered separately,” the researcher clarifies.
The technique developed by Kalmykova and her colleagues will make it possible to notify the population of the danger in a few days, and not in a few hours, as it is now.
Can a tornado be stopped? This question still awaits an answer. As options, scientists propose to spray reagents, to act with powerful microwave radiation and acoustic signals, to erect obstacles in the form of vertical and horizontal grids of various geometries. However, it has not yet been possible to prove the feasibility of these ideas.
Tatiana Pichugina