On the afternoon of March 31, 10,000 mu of pear garden in Tianmiao Township, Yucheng County, Henan Province suddenly encountered a short-term strong wind, which rolled a huge amusement inflatable trampoline into the air. So far, the disaster has killed two children, seriously injured one child, and slightly injured 17 children and 2 adults.
At first, it was rumored online that this was caused by a "tornado". However, experts from the Henan Provincial Meteorological Observatory pointed out that the weather phenomenon of overturning the trampoline is not a "tornado", but is actually a "dust storm". It is rare to cause casualties in dust storms, but be vigilant about it.
Dust storm blows the trampoline into the sky. (Picture from the Internet)
Tornado and dust storm are quite different
Chief forecaster of Henan Provincial Meteorological Observatory pointed out that from 15:00 to 16:00 on March 31, a local dust storm occurred in Tianmiao Township, Yucheng, Shangqiu. The diameter of the dust storm is about 10 meters and lasts about 3 to 4 minutes. The sky was sunny when the dust gush occurred. Monitoring of the regional automatic station showed that the minimum morning temperature of Tianmiao Station in Yucheng, Shangqiu was 1.6℃, the temperature was 17.5℃ at 15 o'clock, the southeast wind was 4 meters per second, and the relative humidity was less than 30%. At Xuzhou Station, 112 kilometers east of the site of the incident, sounding data at 8:00 on March 31 showed that there was no convection unstable energy and the conditions for thunderstorms were not met, which could rule out the possibility of tornadoes.
Meteorological experts said that overall, the sky warmed up significantly when the disaster occurred, the wind speed was small, and the air was dry, which met the meteorological conditions for the dust gush.
What is the difference between a tornado and a dust storm? Meteorological experts say that tornadoes come in rainy days, and dusty days come in sunny days. The occurrence conditions and degree of harm of tornadoes and dust storms are very different.
Experts introduced that tornado is a violent thunderstorm cloud developed in . It is shaped like a funnel hanging from the sky or an elephant's trunk. The strong thunderstorm cloud is its mother body. Tornadoes usually occur on thunderstorms. The diameter of the tornado is generally a few meters to 1,000 meters, and its life span ranges from a few minutes to about one hour.
Dust gush is a whirlwind of very small size generated in the near-ground air layer. It can sweep dust and some tiny objects into the air to form a small dust column. Its appearance is related to the uneven heat exposure of the sun on the ground. Compared with tornadoes, dust storms are smaller, narrower and shorter. The diameter is generally several meters to more than ten meters, and the visible height is generally ten meters, and some can reach one or two hundred meters. The life span ranges from less than one minute to a few minutes, which is rare for more than ten minutes. Dust storms are common in deserts, Gobi, dry river beaches and other areas, especially in hot afternoons in spring and summer.
Dust storm has an elongated inverted conical shape and is a small-scale convective vortex that usually occurs when the ground is strongly heated during the day, causing an instability in the near-ground air. Since the air cannot be turned over the entire layer, a small thermal convection bubble occurs at the concentration of the rising convection. The surrounding wind gives the thermal convection bulb a certain angular momentum . As the heat convection bulb increases, the angular momentum increases with the convergence of the air flow, and a dust gustor forms a central part of the bottom of the thermal convection bulb. Its rotation direction can be clockwise or counterclockwise. Dust, gray sand and other light objects roll up with the wind to form dust columns.
How should we defend against dust gushes?
Central Meteorological Observatory expert told Lanlantian Studio that dust storms are actually very common. In corners, lawns or fields, miniature dust storms that roll up dust and debris can often be seen, rotating and moving forward. But we rarely see their true form when they are truly powerful. Large dust gushes that have developed mature can reach more than ten meters wide and hundreds of meters high, and the central wind force can be greater than level twelve. Large dust storms can pull out trees, lift trucks, roll up heavy objects, and fall down houses to injure people. The extremely high surface temperature and sufficient dust source in the desert often give the dust storm the momentum of sandstorm . When people encounter dust gushings in the desert, they are easily injured, lost, or even buried.
The disaster incident caused by dust storms has also occurred before. For example, on the afternoon of April 3, 2016, a dust storm in Beihai Park in Beijing caused a capsized boat incident.
Dust storm is coming, be careful to avoid it quickly.(Photo source: China Meteorological Administration Propaganda and Popular Science Center)
At present, dust storms are difficult to predict. Meteorological experts told Lanlantian Studio that due to the small size of the dust storm, it occurs suddenly and has a short duration, making it difficult to monitor it by meteorological radar and automatic observation stations, and it is extremely difficult to carry out predictions. If a large dust storm strikes, don’t panic. First judge the direction of the dust storm, then quickly avoid it, stay away from dangerous houses, big trees, billboards, etc., and it is best to hide in a relatively stable building. Nature is ever-changing and unpredictable. We should always be respectful, respect, adapt to, protect nature, and learn and master the necessary disaster prevention and mitigation skills.
(Source: People's Daily Central Kitchen·Blue Sky Studio)
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