Other clouds

Large fires can produce dark clouds similar to large cumulus. Combustion products may be carried by the wind to great distances and occasionally cause a blue appearance of the sun or moon. Real cumulus may also form.

Volcanic eruptions may cause large cumulus-like clouds to form, which can spread out at high altitudes over vast areas. The sky then assumes a peculiar tint, which may persist for several weeks. Very large explosions are usually accompanied by a cloud of smoke or dust above which velum is often seen.

Industrial activities may also produce clouds. The photograph here shows cumulus produced by a power station (cirrostratus is also on the horizon).

Fire clouds, clouds of smoke or dust, clouds from volcanic eruptions and veils of combustion products are ignored when considering the coding for C_L, C_M, C_H and C. However real cumulus and cumulonimbus clouds that may result from such events are reported in the usual way.

Related pages: Cloud classification | C_L guide | C_M guide | C_H guide | Cloud index