What are the four basic categories of clouds?
Well actually, there are only three types of clouds, namely: cumulus clouds, stratus clouds, and cirrus clouds.
They all differ according to their shape and altitude.
CUMULUS CLOUDS looks like puffy and has a flat bottoms. They form at altitudes of 2.4 to 13.5 kilometers. This clouds indicate fair weather. It develops into larger clouds that produce thunderstorms. These large clouds are then called cumulonimbus clouds.
STRATUS CLOUDS layers of clouds that often blocks out the sun. They form at an altitude of about 2.5 kilometers. Light rains and drizzle are usually associated with these clouds.
CIRRUS CLOUDS are feathery or fibrous clouds. They form at very high altitudes usually between 6 and 12 kilometers. It is made of ice crystals and are often call mare's tails. You can see cirrus clouds on a fair weather but after several hours they'll indicate rain or snow.