WeatherEye
Winds Too Quick to Meter 
No one has ever been able to directly measure a tornado's winds. For several years scientists tried, using a reinforced package of instruments called "Toto." The tornado chase teams, however, could never get Toto into the path of a tornado. 

The best speed measurements come from mobile Doppler radar units, carried by scientific tornado chasers from universities. These measurements confirm the amazing power of these concentrated winds.

F0- Wind speeds of 72 mph with light damage. F1 Wind speeds of 73-112 mph with moderate damage.F2 Wind speeds of 113-157 mph with considerable damage.F3 Wind speeds of 158-206 mph with severe damage.F4 Wind speeds of 207-260 mph with devastating damage. F5 Wind speeds of over 260 mph with incredible damage. The Fujita scale shows the range of violence of tornadoes. An F-5 tornado produces the most violent winds on earth, approaching speeds of 300 miles per hour. (In the Fujita scale, the wind speed is inferred by analyzing the damage, it's not measured directly.) 

  • Tornadoes range in width (as measured by the damage path) from less than 150 feet to more than a mile.
  • Tornadoes can last from a few minutes to more than an hour.
  • A tornado can travel along the ground between a few hundred feet to more than 100 miles. 
  • Tornadoes travel along the ground at between 0 and 60 mph.
  • A tornado only becomes a tornado when it touches the ground. Until then, the twisting winds are called a "funnel cloud."
  • Tornadoes over water also have special names; they are called waterspouts. Waterspouts are usually weak. They are most common along the Gulf Coast and southeastern states. 

A type of wind that is often confused for a tornado is a downburst and it's more concentrated version, a microburst. These are downward blowing winds that sometimes come blasting out of a thunderstorm.

Downbursts can have winds as strong as an F2 to F3 tornado and cause damage similar to a tornado's. Downbursts and microbursts, however, blow debris straight away from a point on the ground. A tornado's winds twist in a circular pattern. 

We haven't even talked about why twisters are so phenomenally powerful. 

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This lesson created by "The Why Files," a NISE project funded by the NSF. Lesson used by permission. Original lesson and graphics copyright NISE. Modifications copyright BPNM.