This document describes different types of clouds: - Cirrus clouds occur above 20,000 feet and point in the direction of air movement. They are thin and wispy. - Cumulus clouds are fluffy cotton-like clouds that can be as low as 1,000 feet. They appear fluffy due to rising thermals of air within the cloud. - Cumulonimbus clouds exist from near the ground to 50,000 feet. They are associated with powerful thunderstorms that can produce snow, rain, hail, lightning and sometimes tornadoes. - Stratus clouds form uniform layers below 6,000 feet. Fog results from very low stratus clouds. They are formed when weak