Tornado

Tornado

A Tornado is a rapidly rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. The strongest tornadoes can produce destructive winds with speeds of over 300 mph.

Characteristics

Tornadoes come in many shapes and sizes, but are typically in the form of a visible condensation funnel, whose narrow end touches the Earth and is often encircled by a cloud of debris and dust. Most tornadoes have wind speeds less than 110 miles per hour (180 km/h), are about 250 feet (80 m) across, and travel a few miles (several kilometers) before dissipating.

Formation

The most tornadoes are associated with the supercell thunderstorm. During a supercell, the wind speed and direction change with height. This change in wind speed and direction with height is known as wind shear. This wind shear and the updraft (warm, rising air) interact to create rotation.

Classification

Tornadoes are classified according to the Enhanced Fujita scale (EF Scale), which rates tornadoes by damage caused. An EF0 tornado, the weakest category, damages trees but does not cause significant damage to structures. An EF5 tornado, the strongest category, rips buildings off their foundations and can deform large skyscrapers.

Safety and Preparedness

Tornado preparedness involves having a plan in place before a tornado occurs. This can include knowing the signs of a tornado, having a designated shelter, and being able to quickly move to that shelter when a tornado warning is issued.

See also

• Tornado Alley
• Tornado climatology
• Tornado records
• Tornado intensity and damage