When and where do tornadoes most often occur?

Tornadoes most often occur in the months of March, April and May. Tornadoes mostly occur in the states of Texas, Oklahoma, Nebraska, Kansas, Eastern Colorado and Western Iowa. These states are also known as Tornado Alley because of all the large tornadoes that occur in the states year round.


http://www.nationalatlas.gov/articles/climate/a_tornadoes.html

How fast do tornadoes move?

A tornado can rotate over 200 miles an hour. But when tornadoes move forward they move much slower, when moving forward they only go 30 miles and hour or less. You must also remember that the tornadoes path ranges from 100 yards to one mile, and are normally 15 miles long. They can last for a few seconds to over and hour, so no matter how fast a tornado moves it will still probably be very destructive.

http://www.nssl.noaa.gov/primer/tornado/tor_faq.shtml

How are tornadoes formed?

A tornado is formed by thunderstorms in moist and hot air and advances eastward moving the cold fronts. In the Central Plains, a thing called "dryline" is often developed, which seperates warm, moist air from the east and hot, dry air to the west. Even though tornadoes occur all over the world, the most common area is the United States, so we has Americans have to be very careful.

http://library.thinkquest.org/16132/html/tornadoinfo/formed.html