トマソン　エデンサークルコミュのtornade

This article is about the weather phenomenon. For other uses, see Tornado (disambiguation).

A tornado in central Oklahoma. The tornado itself is the thin tube reaching from the cloud to the ground. The lower part of this tornado is surrounded by a translucent dust cloud, kicked up by the tornado's strong winds at the surface.A tornado is a violently rotating column of air which is in contact with both a cumulonimbus (or, in rare cases, a cumulus) cloud base and the surface of the earth. Tornadoes come in many sizes, but are typically in the form of a visible condensation funnel, with the narrow end touching the earth. Often, a cloud of debris encircles the lower portion of the funnel.

Most tornadoes have wind speeds of 110 mph (175 km/h) or less, are approximately 250 feet (75 m) across, and travel a few miles (several kilometers) before dissipating. However, some tornadoes attain wind speeds of more than 300 mph (480 km/h), stretch more than a mile (1.6 km) across, and stay on the ground for dozens of miles (more than 100 km).[1][2][3]

Although tornadoes have been observed on every continent except Antarctica, most occur in the United States.[4] Other areas where they commonly occur include south-central Canada, south-central and eastern Asia, east-central South America, Southern Africa, northwestern and central Europe, Italy, western and southeastern Australia, and New Zealand.[5]