Dimensions

It's a violent, sometimes lethal, rotating column of air attached to a dense system of anvil-topped rain clouds associated with a thunderstorm.  Tornadoes come in many sizes, typically observed from the ground as a funnel often surrounded by swirling clouds of dust and debris.

Tornado winds generally whirl at 40 miles per hour, but can top 300 miles per hour and travel a few miles before evaporating; a few big cialis online tornadoes can cover a square mile and travel dozens of miles.

The minimum wind speed

of an EF 0 tornado is 40 miles per hour.

Tornado tracks can be just a few feet wide or, as in the case of the tornado that hit Hallam, Neb., on May 22, 2004, 2.5 miles at the ground.  The tri-state tornado in March 1925 tracked for 219 miles along the ground, still a record.

"Tornado" is from the Spanish "tronada" and from the Latin word for thunderstorm.  Tornadoes commonly are called "twisters" as in the title of the 1996 film, or, as in the film The Wizard of Oz, cyclones.