What is the difference between a funnel cloud and a tornado?
A tornado begins as a rotating, funnel-shaped cloud extending from a thunderstorm cloud base. A funnel cloud is made visible by cloud droplets, however, in some cases it can appear to be invisible due to lack of moisture. When the funnel cloud is half-way between the cloud base and the ground, it is called a tornado. The tornado’s high-speed winds rotate about a small, relatively calm center, and suck up dust and debris, making the tornado darker and more easily seen.