How to Identify Different Types of Clouds
Peer into the sky and take note of the clouds around you. Some days, they’re like cotton candy. Other days, they resemble wisps from a paint brush.
A cloud’s appearance — from its shape, size and “texture” — can tell you a lot of information, according to NASA. In simple terms, the sky uses clouds as a way to move water from one location to another. And a cloud’s location in the sky is important, too. The height of a cloud’s base helps determine how it’s classified, according to National Geographic.
Understanding more about clouds can help you foresee approaching weather, and it’s always fun to share your knowledge of clouds. Here are some common cloud types decoded:
The highest clouds can reach over three miles (about 20,000 feet) above ground, says NASA. At this height, the temperature is below freezing, which means clouds at this level are composed of ice crystals. According to the National Center for Atmospheric Research (NCAR), the most common types include small, rounded puffs, called cirrocumulus clouds; white, wispy, feathery clouds called cirrus; and the wide-spreading and sheet-thin cirrostratus. These high clouds are often the first sign of an approaching warm front, and they don’t produce rain, says the National Weather Service.
Mid-level clouds hang out between 6,500 and 20,000 feet, and include grayish-white, altocumulus clouds and grayish-blue sky-covering altostratus clouds, according to the NCAR. The altocumulus is known for its parallel bands or rounded pulled-cotton ball look, says the Department of Atmospheric Sciences at the University of Illinois. If a warm, humid morning brings with it altocumulus clouds (the ones that resemble a flat and uniform texture), pack your umbrella: You can likely expect a thunderstorm in the late afternoon. And if the day brings with it altostratus clouds, continuous rain or snow may roll in, according to the NCAR.
The lowest clouds in the atmosphere are thin, sheet-like stratus, fluffy cumulus, dense cumulonimbus and lumpy stratocumulus, states the NCAR. Stratus clouds are thin and cover the whole sky, and because of their slimness, they sometimes are mistaken for fog. Cumulus clouds are the cotton-ball type you’ll likely see on a sunny day. Cumulonimbus are storm clouds, and can lay low but have a vertical height of up to 50,000 feet or more. These clouds can produce snow, hail and heavy rain, states the NCAR. And the gray, drizzle-making stratocumulus clouds are usually low and lumpy.
Other Types of Clouds
Not every cloud in the sky fits into these categories — contrails, long white streaks formed by water droplets from engine exhaust of high-flying planes, are one example. There are also wall clouds, shelf clouds and the pouch-like mammatus clouds that are often seen after a severe thunderstorm.
Now, as you look up at the clouds of the day, you’ll know how to recognize the difference between a fair-weather cirrus and a seek-shelter cumulonimbus. And when you see a puffy cumulus, don’t forget to ask a friend, “Hey, what’s that one look like to you?”
Originally published on May 1, 2014.