We’ve covered the major cloud types of the lower etage, from the surface to 6,500 feet. The cumulus clouds, from fair weather to thunder, and the layer clouds, stratocumulus and stratus, are the most common ones down here. Moving up to the middle etage, above 6,500 feet on up to 20,000 feet, we’ll begin with altocumulus. This cloud is just like stratocumulus, only higher up. If it’s at 6,500 feet it’s stratocumulus, and at 6,600 it’s altocumulus.
Like stratocumulus, altocumulus is an unassuming cloud. It’s only there because there happens to be enough water vapor in the air to condense out into water droplets. As the temperature drops with altitude, it eventually reaches the dew point and clouds form. Altocumulus has a lumpy appearance because of mild convectivity, but it has minimal vertical development. There’s no drama, other than the visual drama that can come with the right lighting. There’s no threat of exciting weather and precipitation is rare. Altocumulus are just clouds.