Cirriform clouds

These are found at high altitude and consist of ice crystals. There are 3 types of cloud within this group: cirrus, cirrostratus and cirrocumulus.

Cirrus (2) is the most common in Britain and around the world. It’s name is latin for ‘tuft of hair’ which is a good description of the thin, wispy, white cloud. They can be seen moving across the sky despite their high altitude. They can come as a dense patch that is left over from the ‘anvil’ cloud of a cumulonimbus that has disappeared.

Cirrostratus (1) is a thin sheet of cloud which the sun or moon can be seen through. A layer of this cloud can be a sign in a deterioration in the weather.

Cirroncumulus (3) is usually present in small amounts and rarely dominates the sky. On the rare occasions when it is widespread, it can produce a beautiful sunset. They are usually small, individual clouds set in small rows or undulating patterns like ripples.