Cumulonimbus clouds, also known as thunderheads, release hail and rain in conjunction with updrafts. Ice crystals ride such updrafts into the air and then fall through the clouds, collecting water droplets as they drop. Once water droplets freeze onto ice crystals, hailstones are created. Cumulonimbus clouds release rain when they have reached their moisture saturation point.
According to Universe Today, cumulonimbus clouds form rain in the same way that other clouds do. They are essentially masses of condensed water floating in the sky that eventually become so saturated with vapor that they begin to release moisture, which falls to the ground. Cumulonimbus clouds are associated with heavy precipitation and thunderstorms. These clouds tend to form below 20,000 feet and produce lightning by bumping up against each other and creating static charges through ionized water droplets. Not only do cumulonimbus clouds produce typical rain and hail, they sometimes cause flash flooding. However despite the heavy precipitation these clouds generate, such downpours tend to last for only roughly 20 minutes.
The University Corporation for Atmospheric Research reports that cumulonimbus clouds obtain their impressive energy from updrafts and downdrafts, which are essentially vertical winds capable of reaching speeds of 110 miles per hour. These same updrafts are responsible for forming hailstones within the clouds.Learn More
Rain clouds turn gray or black because thick clouds saturated with rain drops scatter sunlight coming through the clouds. When less direct sunlight gets to the bottom of clouds, they appear darker to the human eye. Thin clouds that do not contain a lot of moisture allow enough sunlight through them so that they appear white to observers.Full Answer >
Precipitation occurs when moist air rises to cooler altitudes, condensing the water out of the air into droplets. Once these droplets become heavy enough, often by coalescing around motes of dust or other particles, they fall out of the cloud as precipitation. Without significant updrafts bringing more moisture to the cloud layer, the condensed water may remain light enough to stay aloft, which is why not every cloud brings rain.Full Answer >
Dark rain clouds are called stratus clouds. They are rainy, dense, dark or snowy clouds that sometimes appear as white cottony clumps surrounded by blue sky.Full Answer >
Clouds form when warm, moist air rises into the upper atmosphere, where the cooler temperatures cause the water to condense. Depending on the altitude, clouds may be made up of water droplets or ice crystals, and these often form around floating motes of dust or other particles. When too much moisture condenses, the droplets or crystals become too heavy to stay aloft, falling as snow or rain.Full Answer >