What causes a Tornado?The most common cause of a tornado is from a thunderstorm. Tornadoes form when warm, moist air or air from a thunderstorm meets cooler, dry air creating an unstable atmosphere. After creating an unstable atmosphere, changes in wind direction and wind speed creates a spinning effect near the earth's surface, eventually forming a tunnel of wind that rapidly grows and violently rotates along the earth's surface, destroying homes and uprooting trees that are in it's path.
Where are they most likely to occur?Tornadoes are likely to occur anywhere in the world, but most tornadoes occur in "Tornado Alley," which stretches from Texas to Oklahoma, Nebraska, Kansas and into the Dakotas. The reasoning for "Tornado Alley," is because warm, moist air from the gulf of Mexico mixes with the cooler, dry air from the north creating dangerous tornadoes. Tornadoes can occur during any time of the year, but typically happen during the spring.
What to do in case of a Tornado-If you find yourself in danger of a tornado, it's important that you take shelter to protect yourself. The safest place to be in the case of a tornado is in the basement of your house or the building that you are in.
Do not go near the walls that face in the southern or western directions, this is generally the direction tornadoes move in. You should seek shelter under a stair case, inside a closet or under a heavy table. You should also use a heavy blanket or trash can for protection against debris.
You may also seek shelter in the bathtub, in many homes that have been destroyed by tornadoes, the bathtub plumbing is the only thing left standing. This is because the plumbing is anchored into the ground. If you driving near a tornado, you should leave your car and find shelter inside, you should not keep driving, you may not know what you may encounter on the road. It's also important to realize that a car cannot outrun a tornado.
15 Facts About Tornadoes
1. In order for a vortex to be classified as a tornado, the violently rotating column of air must be in contact with both the cloud above and the ground below.
2. Though tornadoes do occur on other continents, North America’s geography makes it more vulnerable to them. Bradley Smull, an atmospheric scientist at the National Science Foundation, explained yesterday in a Washington Post online chat: “In particular, the proximity of a major north-south mountain range…and the Gulf of Mexico…all in a latitude range frequented by strong upper-level jetstreams amounts to something of a “perfect storm” for severe (supercell-type) thunderstorm formation.”
3. Tornadoes are rated on the Enhanced F (EF) Scale (the old scale was called the Fujita (F) Scale), which assigns a number (0 to 5) based on estimates of 3-second wind gusts and damage. There have been more than 50 F5/EF5 tornadoes recorded in the United States since 1950.
4. Rain, wind, lightning and/or hail may accompany a tornado, but none of them is a reliable predictor of an oncoming tornado.
5. A tornado can last from a few seconds to more than an hour. On average, they persist for about 10 minutes.
6. It is a myth that a tornado cannot pass over features like valleys, mountains, lakes and rivers. When it passes over a lake or river, a tornado becomes a waterspout.
7. Tornado alley is the region in the middle of the United States where tornadoes are most frequent. However, every U.S. state and every continent (except Antarctica) has experienced a tornado.
8. A tornado watch means that conditions are ripe for a tornado; a warning means that a storm has been spotted on the ground or via radar (and you should take cover immediately).
9. Since the first tornado forecast was made in 1948, tornado warning lead times have been increasing and now average 13 minutes. However, they have a 70 percent false alarm rate, which may lead some people to take them less seriously than they should.
10. Mobile homes aren’t more likely to get hit by a tornado than any other type of building, but their flimsy structure provides little protection against strong winds and flying debris.
11. It’s also a bad idea to take shelter in a car—which can be easily tossed about—or under a bridge, where a person would be vulnerable to flying debris or a bridge collapse.
12. The single deadliest tornado killed 695 people in Missouri, Illinois and Indiana on March 18, 1925. The series of tornadoes that struck Tuscaloosa, Alabama and other Southern states in April 2011 set a new record. According to NOAA, there were 312 recorded tornadoes that touched down from 8 a.m. on April 27 through 8 a.m. on April 28. The death toll these storms was over 250 people, and did not break the 1925 record mentioned above.
13. A tornado that struck Washington, D.C. on August 25, 1814, is credited with driving the British invaders out of the city and preventing them from carrying out further destruction. They had burned the White House and much of the city the day before.
14. The city of Greensburg, Kansas was flattened by a tornado in 2007, but instead of abandoning the town, the people are rebuilding with an emphasis on green technology.
15. In 2009 and 2010, more than 100 scientists participated in VORTEX2 (funded by the National Science Foundation and National Oceanic and Atmospheric Administration), which set out to track tornadoes as they formed and moved across the landscape. The V2 researchers are trying to answer many basic questions about tornadoes, such as how, when and why they form, how strong the winds get near the ground, how they do damage, and how predictions can be improved. During the two years, they collected data from dozens of storms and tornadoes. In order for a vortex to be classified as a tornado, the violently rotating column of air must be in contact with both the cloud above and the ground below.