Cumulonimbus, or thunderstorm clouds, produce rain, thunder, lightning, and if conditions are right, tornadoes. Thunderstorms form as the moisture in updrafts-rapidly rising, warm air-condenses into raindrops or hail, which begin to fall when the updrafts no longer have the energy to carry the heavy precipitation. A rainshaft, an area in the cloud where it is raining, is visible in the middle of this image. Thunderstorms can last from one to several hours. The dynamics, microphysics, and societal impacts of thunderstorms are key research areas for scientists at the National Center for Atmospheric Research.
