How Long can a Tornado Last, and How Fast do They Move?

     Tornadoes can last from a few seconds to more than an hour. They might remain on the ground for just a few yards or for more than 100 miles. On average, tornadoes move from the southwest to the northeast at about 30 mph. However, as the killer Jarrell, Texas, tornado of May 27, 1997, showed, tornadoes can defy these averages. The "F-5" tornado that killed 27 people when it churned through a Jarrell subdivision moved southwest at only 10 mph. Tornadoes have been known to move in any direction at speeds up to 70 mph. Some have sat nearly stationary for several minutes. But, it is unusual for tornadoes to change speed and direction during their lifetime.
     The winds inside a twister can spin around at speeds up to 500 miles an hour, but usually travels at roughly 300 miles an hour. This makes the tornado the most dangerous storm known to mankind. Because of the earth’s unique weather system, twisters rotate counterclockwise in the Northern Hemisphere and move eastward. They rotate clockwise in the Southern Hemisphere. Tornadoes also often come with hailstorms.
     Many storms create harmless funnels that never touch earth. They can last from a few seconds to a few hours. Others disappear and reappear minutes later. The average tornado has a diameter of about 200 to 300 yards, and some grow large enough to spawn smaller tornadoes known as satellite tornadoes. These small offspring, about 50 yards across, can be very fierce and do lots of damage. They also tend to branch away from the parent funnel, taking separate paths across the earth.
     It can travel across the ground at high speeds, then just as suddenly vanish. They can kill in a matter of seconds. Every year, about $500 million worth in damage is done by twisters in the United States. Most tornadoes last less than twenty minutes and travel less than 15 miles. However, superstorms sometimes occur, traveling over 100 miles before they are exhausted. Although they don’t occur very often, they are responsible for 20% of all tornado casualties.