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Tornadoes 101 | National Geographic

Feb 20, 2020
- They begin their lives as ghosts, gently passing through a solitary existence, but little by little, their gentleness turns to rage. They grow larger and larger, lunging and twisting and desperately descending from the sky, and what began as an invisible shadow becomes a monster. (foreshadowing music) Tornadoes are powerful rotating columns of air that extend from the ground to the clouds. Most are relatively weak, but the few that grow into major events are extremely violent and cause immense destruction. Tornadoes occur on six of the seven continents. The country with the most

tornadoes

according to the size of the territory is the United Kingdom, with an average of around 33

tornadoes

each year.
tornadoes 101 national geographic
But the country with the highest total number of tornadoes and the most intense is the United States, with more than 1,000 reported annually. Tornadoes, regardless of where they occur, are classified as supercell tornadoes, which form within supercells, the most powerful class of thunderstorms, or non-supercell tornadoes, which are smaller and weaker and form within non-supercell storms. There are many theories about the formation of tornadoes. A key component they share is the presence of both high and low pressure air in a given space. Air particles from the high-pressure area move toward a low-pressure area, a movement that creates wind.
tornadoes 101 national geographic

More Interesting Facts About,

tornadoes 101 national geographic...

Non-supercell tornadoes, such as waterspouts and landspouts, start when cold high-pressure air and warm low-pressure air are present, particularly near ground level. As air particles move horizontally from the high pressure area to the low pressure area, the wind begins to pick up. Winds blowing at different speeds and in different directions and altitudes begin to blow cyclically. For tornadoes that are not supercells, they become a vertical rotating vortex. But to create supercell tornadoes, the circumstances are slightly different. Violent supercell storms draw warm, low-pressure air to a higher altitude, leaving behind cold, high-pressure air near the ground. Air particles trying to balance the two levels of air pressure create wind that blows vertically.
tornadoes 101 national geographic
The wind increases and begins to blow cyclically, creating a wind tube that rolls along the ground. In both cases, an upward current of wind called an updraft provides the final ingredient to create a tornado. In a budding non-supercell tornado, an updraft extends its vertical vortex until it reaches the clouds. To create a supercell tornado, an updraft lifts the wind tube until it remains vertical. It then draws condensation from the heavens into the rotating vortex. As soon as vortices, supercells or non-supercells, connect the ground to the clouds, they are officially classified as tornadoes. All tornadoes are classified according to a system called the Enhanced Fujita Scale.
tornadoes 101 national geographic
The Enhanced Fujita Scale, or EF, rates tornadoes as EF0 to EF5. The rating is based on a number of factors, such as the damage a tornado causes and Doppler radar estimates of wind speed. EF0 tornadoes are the weakest, with wind speeds between 65 and 85 miles per hour. EF5 tornadoes are the strongest, with winds exceeding 200 miles per hour. One of the strongest tornadoes on record occurred in Oklahoma City, Oklahoma, in 1999. Born from a supercell storm, the EF5 tornado had wind speeds of more than 300 miles per hour. It resulted in 36 deaths, nearly 600 injuries, and around $1 billion in damage. (somber music) (dramatic music) While tornadoes cannot be prevented, steps are being taken to protect communities.
Meteorologists closely monitor storm fronts in high-risk areas and try to forecast possible tornadoes. In doing so, they help mitigate damage to neighborhoods and save countless lives, even in the face of one of nature's most formidable phenomena.

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