Camanchacas are marine stratocumulus cloud banks that form on the Chilean coast, by the Earth's driest desert, the

Atacama Desert The Atacama Desert ( es, Desierto de Atacama) is a desert plateau in South America covering a 1,600 km (990 mi) strip of land on the Pacific coast, west of the Andes Mountains. The Atacama Desert is the driest nonpolar desert in the w ...

, and move inland. In Peru, a similar fog is called garúa, and in Angola cacimbo. On the side of the

mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...

s where these cloud banks form, the camanchaca is a dense

fog Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Reprint from Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily inf ...

that does not produce

rain Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water ...

. The moisture that makes up the cloud measure between 1 and 40

microns The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer ( American spelling), also commonly known as a micron, is a unit of length in the International System of Un ...

across, too fine to form rain droplets.

Fog collection

In 1985, scientists devised a fog collection system of

polyolefin A polyolefin is a type of polymer with the general formula (CH2CHR)n where R is an alkyl group. They are usually derived from a small set of simple olefins ( alkenes). Dominant in a commercial sense are polyethylene and polypropylene. More speci ...

netting to capture the water droplets in the fog to produce running water for villages in these otherwise

desert A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one ...

areas. The Camanchacas Project installed 50 large fog-collecting nets on a mountain ridge, which capture some 2% of the water in the fog. In 2005, another installation of panels of producing per square meter per day.

References

Stratus Climate of Chile Fog {{chile-stub