When do clouds form?
Clouds form when moist air cools. Moist air is air that contains water vapor (an invisible gas). In nature, air cools as it rises away from the ground; it also cools when it mixes with a colder air mass. At a certain cooler temperature (the “dew point”) which depends upon the amount of water vapor in the air, the water vapor condenses into tiny, visible water droplets. We see these tiny droplets as clouds. If they are very close to the ground we see them as fog. These droplets are not big enough to fall as rain. 10. Are there different kinds of clouds? Yes. The highest clouds are typically about 17,000 to 50,000 feet above the ground. These are the cirrus clouds which are composed of ice crystals and appear as white, silky filaments, patches or bands. Clouds that form beneath cirrus clouds include the stratus or flat, layered clouds. Nimbus clouds are also lower than cirrus; they are dark, rain clouds The clouds that form closest to the ground are cumulus or heaped clouds which have a
