History of tornadoes

If there are more than six tornadoes in one day, it can be called "tornado outbreak"

1On April 3, 974, the second largest tornado in history produced 148 tornadoes, including 6 EF5 tornadoes and 24 EF4 tornadoes, nicknamed "Super Outbreak". Another storm outbreak of similar intensity was "Palm Branch All-Day Tornado Outbreak" (1965), which hit the Midwest of the United States on April 1965, killing 27 1 person. In addition, on April 25-28, 20 1 1, a tornado of similar scale also broke out (the tornado broke out on April 25-28, 201///), and 330 tornadoes were diagnosed and 344 people died (238 in Alabama alone in these four days) On the 27th, there were 190 tornadoes, including 4 tornadoes with the magnitude of EF5 (two of which occurred between Mississippi and Alabama) and1tornado with the magnitude of EF4, which was the most serious tornado disaster after the 1974 "super outbreak". April this year set a record for the largest number of tornadoes in a single day and month over the years, so the United States also called this tornado outbreak "20 1 1 super outbreak" or "super outbreak II".

2065438+At 0: 30 am on April 29th, 2002, a tornado suddenly appeared in Fengshan Industrial Zone, Bang Qi Village, Xinhui District, Jiangmen City, Guangdong Province, China, causing 22 factories with a total area of more than 23,000 square meters to be razed to the ground.

1995 In a tornado in Admore, Oklahoma, USA, heavy objects such as roofs were blown dozens of miles away. Most of the debris falls on the left side of the tornado passage, and there are often obvious landing areas according to the weight. Lighter debris may fly more than 300 kilometers before landing.

Under the attack of a strong tornado, the roof of the house will fly like a glider. Once the roof is swept away, the rest of the house will collapse. Therefore, if we can strengthen the stability of the roof when building houses, it will help to prevent the tornado from causing huge losses when crossing the border.

The tornado struck suddenly and violently, and the wind force produced was the strongest on the ground. In the United States, the number of deaths caused by tornadoes is second only to lightning every year. Its damage to buildings is also quite serious, often devastating.

1626 (the sixth day of may, Xi, Ming Taizu) at 9: 00 am on may 20th, a bizarre disaster suddenly broke out around Beijing Wang Gong factory (now Xuanwu gate, Beijing). The official news and communication publication "Tian Bian Di Chao", which has important historical value in Ming Dynasty, recorded the disaster in detail, and the extract is as follows: "The east corner of Jizhou City collapsed, with hundreds of rotten houses. On the tenth day, two people were dug out of the ground and still alive. Asked, the cloud:' drunk as a dream'. Dig another old man to live. " In the catastrophic disaster of Wang Gong factory, what force can make three people fly from Beijing to Jizhou 180 without dying? There must be some inevitable factor at work, but can human beings recognize this inevitable factor in the future? Can this magical power be mastered, controlled and utilized by human beings in the future?

1On May 27th, 999, four counties in central Texas, including Austin, the capital, were hit by a huge tornado, killing at least 32 people and injuring dozens. It is reported that in jarrell, 40 miles north of Austin, more than 50 houses collapsed and more than 30 people were killed in the tornado. The damaged area is 1 mile long and 200 yards wide. This is another tornado area in the United States after Miami was hit by a tornado on May 3, 65438.

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. It is not surprising that the wind speed is 100 m per second, even reaching more than 175 m 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.

1 On May 3, 1999, Oklahoma, USA, was hit by an EF5 tornado with a wind speed as high as 5 12km per hour, which was extremely destructive and with a width of 1.5km. This tornado killed 44 people, and the homes of110,000 people were razed to the ground, resulting in heavy losses.

20 14, 16 On June 6, at least two tornadoes hit northeastern Nebraska, USA, and a small town was seriously damaged. Up to now, at least 1 person is known to have died and 28 people were injured, of which 16 was seriously injured, and the situation is critical. Nebraska Governor Heineman declared a state of emergency in the region. The National Guard was ordered to be dispatched to assist local departments in disaster relief and relief for the victims.

The worst disaster is pilger Town, with only 370 residents. It is estimated that as many as half of the houses were destroyed and some were razed to the ground. A middle school and a farmer's cooperative in the town were seriously damaged. Rescuers rescued five people from the day care center.

The town is located in the northwest of Omaha, Nebraska 160 km. After nightfall, the police and emergency personnel should evacuate the residents of the town, arrange for them to live in temporary shelters and close all roads leading to the town.

50% to 75% of the whole town was severely damaged or destroyed. That middle school alone was completely destroyed. Residents described the tornado as "unbelievable".