Funnel cloud
Encyclopedia : F : FU : FUN : Funnel cloud
Funnel clouds are directly related to tornadoes. By definition, a funnel cloud is any rotating column of air extending from the base of a cloud (usually a cumulonimbus or towering cumulus cloud) but not reaching the ground. All tornadoes begin life as a funnel cloud, and many funnel clouds will not become a fully fledged tornado if they never make ground contact. A funnel cloud is usually visible as a cone-shaped or needlelike protuberance from the main cloud base.
Funnel clouds frequently form in association with supercell thunderstorms, and these funnel clouds are a threat to become tornadoes if their circulation reaches the ground. Sometimes the visible funnel cloud may not reach all the way to the ground, but if a debris swirl is present on the ground underneath the funnel, a tornado exists. Conversely, some tornadoes may appear only as a debris swirl, with no obvious funnel extending below the rotating cloud base. If a funnel cloud makes ground-level contact over water, it is generally termed a waterspout. However, it is important to note that the actual structure of a common waterspout is quite different from that of a tornado. Many waterspouts are not actually tornadic, despite their deadliness. (([Disputed statementdisputed]—see [
