A localized, violently destructive windstorm occurring over land, especially in the Middle West, and characterized by a long, funnel-shaped cloud extending toward the ground and made visible by condensation (water vapor turning into clouds) and debris (materials).

How Do They Form?

When a thunderstorm meets horizontal (sideways) winds at a high altitude (high in the air).  These winds cause the warm air that is rising in the thunderstorm to spin. A storm cloud may form a thin funnel shape that has a very low pressure (packed air that has more mass than the surrounding areas) center.  As the funnel reaches the ground, the higher pressure air (Air that has less mass than its surroundings) collides with the low pressure area.  The result is very high wind speeds.

The Tri-State Tornado

  • 695 deaths, and 2,027 people were injured
  • The tornado traveled over 300 miles through Missouri, Indiana, and Illinois
  • March 18, 1925
  • Damage was estimated as $18 million in 1925 money

Joplin, Missouri Tornado

  • 158 deaths, and more than 1,000 people were injured
  • winds got up to 200 mph
  • May 22, 2011
  • Tornado was on the ground for more than 22 miles
  • around 7,000 homes and buildings were destroyed

How to prevent deaths and injuries?

  • Scientists collect data from radars, observation stations, weather balloons, planes, and satellites
  • When scientists spot a tornado on their tools an alarm is set off that all of the town/city can hear
  • People go into an underground area because once a tornado is touching the ground it cannot travel any lower.


Works Cited

Staff, CNN. "The 10 Deadliest U.S. Tornadoes on Record." CNN. Cable News Network. Web. 13 Mar. 2015. <>.

"Weather Wiz Kids Weather Information for Kids." Weather Wiz Kids Weather Information for Kids. Web. 08 Mar. 2015. <>.

"The Science of Tornado Prediction: Can Technology Keep Us Safe from Future Storms?" The Verge. 23 May 2013. Web. 17 Mar. 2015. <>.

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