According to US media reports, 6 states in the central United States were hit by at least 30 tornadoes on the night of the 10th, and the tornado disaster has caused more than 100 deaths so far.
"This could be one of the biggest tornadoes in our history." US President Biden said on the 11th.
Satellite cloud map of tornado disaster released
Move rapidly from the central united states to the east
The National Oceanic and Atmospheric Administration released a satellite image on the 11th, releasing a cloud map of the U.S. tornado disaster taken from space. From the picture, you can see that a large cloud formed by strong convective weather moves rapidly from the central United States to the east, interspersed with continuous blue lightning. It was beneath these dark clouds that a series of tornadoes struck many U.S. states, causing severe damage.
The United States advanced in early warning
Tornadoes remain difficult to predict accurately
The New York Times quoted meteorological experts as saying on the 11th that in general, tornadoes are relatively small-scale and relatively short-duration meteorological events, but this tornado seems to have erupted in a large "cluster", which is also a trend of tornado disasters in the United States in recent years.
Dan Pidnoski, a senior meteorologist in the United States, said on the 10th, "This is what we call a tornado cluster outbreak, that is, a storm system produces a large number of tornadoes in a large geographical area." But it is highly unusual for such a "large and robust" storm system to appear in December, which is usually not seen in the region until May or April.
Tornadoes are produced by strong convective movement of air in extremely unstable weather, often accompanied by high-speed rotating funnel-like cloud columns, and the wind speed near the center can reach 100 meters to 200 meters per second, and the highest even reaches 300 meters, which is several times greater than the maximum wind speed near the center of the typhoon (generated at sea), which is extremely destructive. Everywhere the tornado went, there was devastation: broken bricks and tiles, trees that were "cut down", cars that were smashed beyond recognition...
Relevant experts pointed out that meteorologically, tornadoes belong to strong convective weather, it occurs suddenly, moves rapidly, and is extremely destructive, accurately predicting when and where it will occur in a day, and where it will pass, has always been a worldwide problem.
The United States is a veritable country of tornadoes, and according to the National Oceanic and Atmospheric Administration, the average number of tornadoes in the United States is about 1250 times a year. Tornadoes are difficult to predict because its horizontal scale (diameter) is very small, small-scale weather events have strong spatio-temporal randomness, meteorological detection equipment and detection systems can not effectively and accurately monitor and track the occurrence and development of tornadoes, accurate forecasting is more difficult, even in the United States such an advanced country of tornado warning, it is still difficult to accurately forecast.
On December 11, houses in Mayfield, Kentucky, UNITED States, collapsed in a tornado attack. Xinhua News Agency (Photo by Carromina Sanchez)
The losses were significant
Occurs more and more frequently
In 2011, the strong storm weather that ravaged the southern United States killed 329 people and injured more than 1,700, including a tornado that directly killed 158 people. Nearly ten states, including Alabama, Mississippi and Tennessee, declared a state of emergency. According to U.S. media reports at the time, some residents of the tornado-hit area said that just a few minutes after the warning of a tornado was issued on the radio, it really came and could not be avoided.
And even if the weather department can issue an early warning more than 20 minutes in advance, the tornado can still cause significant damage. An American meteorologist said that the tornado moves so fast that if it happens to fall into a relatively densely populated place, it is inevitable to cause heavy damage.
For the sake of rigor, scientists generally do not make up their minds about the deeper causes of the current frequency of extreme weather such as tornadoes, because climate research requires years of scientific tracking statistics, and it is possible to reach more certain conclusions on the basis of a large amount of data. However, by observing the occurrence of extreme weather in recent years, it is not difficult to find that they have a higher and higher frequency in the 21st century.
Upstream news is synthesized from CCTV News, Xinhua News Agency, etc