It is very rare to see a pileus cloud feature in a painting. This accessory cloud looks like a delicate, smooth cap over the summit of a building storm cloud. Pileus featured in the painting Sky – Northern Cuba by nineteenth-century American artist Charles Dewolf Brownell, forming above one of the mounds at the top of the large Cumulus congestus cloud dominating the skyscape.

A pileus often obscures the summit of the cloud it develops on, just like this one does. It is formed as the air rushing up within the building storm lifts stable air above just enough for it to form into a gauze-like cloud cap. Also featured in Brownell’s masterful cloudscape are patterns of the mid-level cloudlets called Altocumulus (in the top part) and, off near the horizon, low layers of clumpy cloud called Stratocumulus and dark cloud shreds associated with stormy conditions known as pannus.