Clouds are composed of water, tiny particles of dust and sometimes ice. They have important effects on the earth's temperature; they can trap heat in the atmosphere or they can block out the sun's rays. Clouds are divided into types based on multiple factors, including size, color, elevation and composition. Each type of cloud has a Latin name and may fall into one of the four basic cloud groups. Since cloud formations and movements signal different weather patterns, you can predict the weather forecast if you know which types of clouds are in the sky.
Cirrus clouds are high-altitude ice clouds that range from 20,000 to 40,000 feet up in the sky. Cirrus clouds are separate white bands or streaks of clouds that line a clear sky. They typically look wispy, silky and hairlike and are sometimes called "mares' tails," "spider webs" or "painters' brushes." The clouds are associated with pleasant or fair weather. Cirrocumulus is a type of cirrus cloud that appears as sheets or layers of small, rounded white puffs in the sky. Cirrocumulus clouds can look like fish scales and give an appearance of a "mackerel sky." Cirrostratus is another type of cirrus cloud. These clouds are transparent, thin, sheetlike clouds that can cover the entire sky. The transparency of the clouds allows you to still see the sun or the moon through them.
Alto clouds are middle-level altitude clouds that can range anywhere from 6,500 to 20,000 feet up in the sky. One type of alto cloud is the altocumulus. If these clouds appear on a warm and humid summer morning, they typically tend to presage late afternoon thunderstorms. Altocumulus clouds are white or gray in color and composed of water droplets. The clouds can appear in the shape of puffy masses, flattened layers or parallel bands or waves across the sky. Another type of alto cloud is the altostratus. Altostratus clouds are gray or blue-gray in color and tend to appear ahead of rainy weather.
Stratus clouds are gray clouds that hang below 6,500 feet and may accompany precipitation. Stratus clouds have a resemblance to fog and can cover the entire sky. A type of stratus cloud is the nimbostratus. This cloud indicates a wet weather front. The clouds are dark gray in appearance and produce rain or snow. Another type of stratus cloud is the stratocumulus. Stratocumulus clouds are typically low, lumpy-looking cloud layers that are dark gray to light gray in color. They can appear as rounded masses or rolls and can produce light precipitation.
Cumulus clouds appear as "heaps" of detached, puffy white clouds in the sky. These clouds can develop vertically and form domes or mountains of clouds. The tops of the clouds have rounded towers and the bottoms of the clouds are flat and can hover 330 feet above the ground. A type of cumulus cloud is the cumulonimbus. Cumulonimbus clouds can reach high altitudes of over 39,000 feet and indicate very stormy weather. These clouds can produce threatening storms of lightning, thunder or tornadoes.