Description Cirrostratus and differences with similar clouds | Previous Top Next

Cirrostratus
Transparent, whitish cloud veil of fibrous (hairlike) or smooth appearance, totally or partly covering the sky, and generally producing Halo phenomena.
Main differences between Cirrostratus and similar clouds of other genera
(a) Cirrus
Cirrostratus is distinguished from Cirrus by the fact that it occurs in the form of a veil which is usually of great horizontal extent.
(b) Cirrocumulus and Altocumulus
Cirrostratus has a diffuse general aspect and does not exhibit such features as grains, ripples, laminae, rounded masses, rolls, etc., which are characteristic of Cirrocumulus and Altocumulus.
(c) Altostratus
Cirrostratus differs from Altostratus by its thinness and by the fact that it may show Halo phenomena. Cirrostratus near the horizon may he mistaken for Altostratus. The slowness of the apparent movement and the slowness of the variations in thickness and in appearance, both characteristic of Cirrostratus, give useful guidance in distinguishing this cloud from Altostratus and also from Stratus.
(d) Stratus
Cirrostratus may he confused with very thin Stratus which, at angular distances of less than 45 degrees from the sun, may appear very white. Cirrostratus differs, however, from Stratus by being whitish throughout, and by the fact that it may have a fibrous appearance. Moreover Cirrostratus often displays Halo phenomena, whereas Stratus does not, except occasionally at very low temperatures.
(e) Haze
Cirrostratus differs from a veil of haze by the fact that the latter is opalescent or has a dirty yellowish to brownish colour. It is sometimes difficult to discern Cirrostratus through haze.