BIOL1300 Lecture Notes - Lecture 35: Funnel Cloud, Jet Stream, Fujita Scale
Document Summary
Most tornadoes occur in the lower midwestern states during the spring. Tornadoes have high wind speeds and cause devastation along their tracks. When multiple weather systems collide, violent, cyclonic storms can develop. This process creates the type of storm that generates most tornadoes. Single-cell storms (warm air rising and precipitation falling) usually do not generate a tornado. Usually air from the gulf of mexico. Usually air from canada or the rocky mountains. Warm air (moving up) and cold air (moving across) collide. High-altitude jet stream winds add to the rotation and shear. Because these three air masses move in different directions, wind shear is present. The wind shear can spin thunderclouds, creating the conditions for tornado formation. As spinning vortices stretch and elongate, they must spin faster in order to conserve angular momentum. Vortices become faster as they become thinner.