A funnel cloud is a cloud, generally shaped like a funnel, which usually extends from the base of a cumulus congestus or cumulonimbus cloud, and which is composed of water droplets in a rotating column of air. It is often seen in the first and second stages of tornado formation. The funnel cloud may be seen in other situations, but is most known for its appearances prior to the completion of tornado development. After a funnel cloud forms it may reach the ground after extending further from its associated cloud, becoming a tornado, which is a powerful storm known for causing destruction. Alternatively, a funnel cloud may touch down over water and become a waterspout, or it may dissipate without reaching Earth at all. If one sees a funnel cloud start forming, it may be in one's best interest to take cover and go to a low place before a tornado potentially forms.