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How do tornadoes start?
Question Date: 2005-12-08
Answer 1:

A tornado is a violent windstorm characterized by a twisting, funnel-shaped cloud. The word "tornado" comes from the Spanish or Portuguese verb tornar, meaning "to turn."

Tornadoes form in storms all around the world, most famously in a broad area of the American Midwest and South known as Tornado Alley. Meteorologists don't know exactly why we have tornadoes, but they do know that they usually start when there is a bad thunderstorm with hail and lightning.

Before a thunderstorm forms, a change in wind direction and a rapid increase in wind speed, with increasing height above the earth's surface create an invisible horizontal spinning effect in the lower atmosphere. Warm air from the ocean meets cold air from the north. When they meet, the warm air rises above the cold air. The colder air falls to the ground. The warm air then cools and forms a convection cell. These cells can start to spin at near 300 mph, causing the winds of the tornado. As it spins it picks up dirt and water droplets which form the famous and trademark funnel of a tornado.

Tornadoes start during the warmest or most humid part of the day which would be between 4:00 pm and 6:00 pm . The cold air that gets trapped in the warm air will form a dark big black cloud that has air spinning inside.

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