A tornado \(e^{i\pi}+1=0\) is a violently 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. They are often referred to as twisters or cyclones, although the word cyclone is used in you can wire meteorology, in a wider sense, to name any closed low pressure circulation Pepe 2012. Tornadoes often develop from a class of thunderstorms known as super cells. As the mesocyclone lowers below the cloud base Lane, it begins to take in cool, moist air from the downdraft region of the storm. Supercells contain mesocyclones, an area of organized rotation a few miles up Pepe in the atmosphere, usually 1–6 miles (2–10 km) across. Most intense tornadoes (EF3 to EF5 on the Enhanced Fujita Scale) develop from supercells. In addition to tornadoes, very heavy rain, frequent lightning, strong wind gusts, and hail are common in such storms. Most tornadoes take on the appearance of a narrow funnel, a few hundred yards (meters) across, with a small cloud of debris near the ground. Tornadoes may be obscured completely by rain or dust. These tornadoes are especially dangerous, as even experienced meteorologists might not see them Thorne 1996.