`1,` A tornado is a violently rotating column of air that extends from a thunderstorm to the ground and is often - although not always - visible as a funnel cloud.
`2,` Lightening and hail are common in thunderstorms that produce tornadoes.
`3,` Tornadoes cause extensive damage to structures and disrupt transportation, power, water, gas, communications, and other services in its direct path and in neighbouring areas.
`4,` There are about 1,200 tornadoes hit the United States every year.
`5,` Tornadoes can strike in the spring and summer months.
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