Difference Between Heap Clouds And Layer Clouds
Meteorologists divide clouds into two rough classifications—heap clouds and layer clouds. Heap clouds are also known as cumulus clouds, and layer clouds are also known as stratus clouds. Some clouds are a combination of these two types. A few clouds fall into neither classification.
Cumulus clouds are flat on the bottom but lumpy and rounded on the top—hence the description “heap.” When a few small cumulus clouds dot the sky, it is a sign of fair weather. On the other hand, tall, bulky cumulus clouds can produce violent storms called thunderstorms, which are marked by heavy rain, thunder, and lightning. Such clouds are known as cumulonimbus clouds, or thunderheads. (The suffix “nimbus” refers to clouds that produce rain.) The arrival of thunderheads often signals the approach of a cold front. Cumulus clouds are more common on a sunny day, when the humidity is high. Cumulus clouds usually begin to form in mid- to late morning and are most common in the early afternoon.
Stratus clouds are flat, sheetlike clouds that can spread across the sky from horizon to horizon. They commonly form when warm air rises over cold air, as in a warm front. Stratus clouds often signal the approach of a warm front. When stratus clouds produce precipitation, it is usually drizzly and can be long-lasting.
Under certain conditions, clouds can form that combine the characteristics of stratus and cumulus clouds. A stratocumulus cloud, for instance, has the appearance of cumulus clouds that have been flattened out into a layer. Stratus clouds and cumulus clouds can be found high above the ground, too. Altostratus and altocumulus clouds occur at heights of about 2 miles (3 kilometers) above the ground. (The prefix “alto” means “high.”) When altostratus clouds produce rain or snow, they are referred to as nimbostratus clouds.