A cloud, in terrestrial meteorology, is a visible mass of condensed droplets, frozen crystals suspended in the atmosphere above the surface of Earth. The branch of meteorology in which clouds are studied is nephology.

On Earth the condensing substance is typically water vapor, which forms small droplets or ice crystals, typically 0.01 mm in diameter. When surrounded by billions of other droplets or crystals they become visible as clouds. Dense deep clouds exhibit a high reflectance (70% to 95%) throughout the visible range of wavelengths: they thus appear white, at least from the top. Cloud droplets tend to scatter light efficiently, so that the intensity of the solar radiation decreases with depth into the cloud, hence the gray or even sometimes dark appearance of the clouds at their base. Thin clouds may appear to have acquired the color of their environment or background, and clouds illuminated by non-white light, such as during sunrise or sunset, may be colored accordingly. In the near-infrared range, clouds would appear darker because the water that constitutes the cloud droplets strongly absorbs solar radiation at those wavelengths... (Read more)

• that Stratus clouds most commonly form near the coast and mountains?
• that Cumulonimbus incus can cause tornadoes?
• that clouds are formed by condensation?

Cirrus intortus - Cirrus radiatus - Cumulonimbus - Mammatus - Pileus - Cumulus - Funnel cloud - Nimbostratus - Nimbus - Fog

category:Stratocumulus clouds

category:Cumulus clouds

category:Cumulonimbus clouds

category:Altostratus clouds

category:Altocumulus clouds

category:Cirrus clouds

category:Cirrostratus clouds

category:Cirrocumulus clouds

category:Contrails

category:Atmospheric phenomena

category:Precipitation