Tornado prevention measures

There is no separate tornado warning in China. For ordinary people, they should master relevant defense knowledge in order to effectively save themselves and each oth

There is no separate tornado warning in China. For ordinary people, they should master relevant defense knowledge in order to effectively save themselves and each other when disasters occur. So, what should I do when there is tornado weather? Come and have a look with me!

The cause of tornado

Tornado is the strongest vortex phenomenon in the atmosphere. It is a strong wind vortex with small range and strong wind force extending from the bottom of thunderstorm cloud to the ground or water surface. Summer often occurs in thunderstorm weather, especially in the afternoon to evening. Although the scope of influence is small, it is extremely destructive.

Water vapor rises to the sky and condenses to form clouds. At high altitude, the temperature of the cloud is relatively low, and the surrounding water vapor is constantly cooling and shrinking, so that the water vapor in the surrounding air constantly supplements the remaining space reduced by condensation. Because the water vapor rising under the cloud rises linearly, the water vapor molecules are cooled during the rising process, and the volume shrinkage is getting smaller and smaller, and it gradually becomes funnel-shaped due to the geostrophic bias. At this time, the gas molecules under the cloud are constantly replenished into the space, and the pressure difference is getting bigger and bigger, resulting in strong winds, and the gas in some surrounding spaces is uneven, forming a tornado.

Generally speaking, a tornado is a whirlwind. When it touches the ground, its diameter ranges from several meters to 1 km, with an average of several hundred meters. Tornadoes range from a few meters to dozens of kilometers, and things are robbed everywhere. The funnel-shaped center of tornado is composed of inhaled dust and condensed water vapor, which is a visible "dragon mouth". On the ocean, especially in the tropics, similar scenes are called sea tornadoes.

Most tornadoes rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere, with some exceptions. The exact mechanism of tornado formation is still under study, and it is generally believed to be related to the violent activities of the atmosphere.

Since19th century, the accuracy of weather forecast has been greatly improved, and various disasters and storms such as tornadoes and hurricanes can be detected by weather radar.

Tornadoes are usually extremely fast, and it is not surprising that the wind speed is 100 meters per second, even reaching more than 175 meters per second, which is five or six times larger than the typhoon 12. The range of wind is very small, generally the diameter is only 25~ 100 meters, and only in rare cases can the diameter reach more than one kilometer; It takes only a few minutes from occurrence to disappearance, at most a few hours.

Tornadoes are also very powerful. There was a tornado 1956 in Shanghai on September 24th. It easily lifted a large oil storage barrel weighing 220,000 Jin to the altitude of15m, and then threw it away from120m.

1879 at 4 pm on may 30, two dark and thick clouds were merging over northern Kansas. After 15 minutes, a vortex was generated at the lower end of the cloud. The vortex has grown rapidly and become a huge pillar of indomitable spirit. Within three hours, it ran wild all over the state like a dragon, and no one was spared wherever it went. However, the strangest thing happened at the beginning, when the tornado whirled across a small river and met a cliff. Obviously, it is impossible to surpass this obstacle, so the vortex turns to the west, and there happens to be a newly built 75-meter-long railway bridge over there. The tornado vortex actually pulled it down from the stone pier, twisted it a few times, and then threw it into the water.

Precautionary measures for tornadoes

1, the safest place is the concrete basement. Tornadoes have the characteristics of jumping forward, often landing for a while and flying for a while. It has also been found that after the tornado, a narrow destruction zone will be left, and the objects next to the destruction zone are safe even if they are close at hand. Therefore, when encountering a tornado, people should keep calm, actively try to avoid it, and never panic. You know, the basement of concrete building is the safest place. People should be as low as possible, especially don't stay on buildings. In addition, relatively speaking, small houses and secret rooms are safer than large rooms.

2. Look for low-lying areas perpendicular to the tornado path to hide. It is very dangerous if someone happens to meet a tornado while driving in the wild. Because tornadoes can not only suck up cars and people along the way, but also cause a huge pressure difference between inside and outside the car, causing an explosion, so people in the car should abandon their cars and run to nearby shelters. If it is too late to escape, it is necessary to make a decisive decision and quickly find a low-lying area perpendicular to the tornado path, such as a ditch. Tornadoes always "go straight", just like sprinters, it is difficult to turn sharply.

3. Run into the house near the big tree to hide. People only saw trees uprooted or broken by tornadoes, but they didn't find them "thrown" into the distance. This is probably because trees have a certain windproof effect. 1On June 27th, 1985, a tree with a diameter of more than 1m and a height of more than 10m was uprooted by a tornado, and two other trees nearby were blown off. The house 3 meters away from the tree was not damaged in autumn, but six new brick houses 30 meters away from her home were destroyed because there were no trees nearby. It can be seen that planting more trees in front of and behind the house can resist the attack of tornado.

Emergency prevention suggestions for tornadoes

1 When you are at home, be sure to stay away from doors, windows and the outer wall of the house, and hide in the wall or small room opposite the tornado. The safest place to avoid a tornado is the basement or semi-basement.

2 In case of emergency, such as pole collapse or house collapse, the power supply should be cut off in time to prevent electric shock or fire.

When there is a tornado outside the venue, you should look for low-lying land nearby, but stay away from trees and telephone poles to avoid being smashed, crushed and electrocuted.

4 When the car encounters a tornado when going out, don't drive to avoid it, and don't avoid it in the car, because the car has almost no defense against tornadoes. Leave the car immediately and avoid it in a low-lying place.