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Atacama Desert

Atacama Desert



Area: 40,600 mi2 (105,200 km2)

Average rainfall: 0- 0.08 in a year




Description of Atacama Desert

Atacama Desert is situated on the coast of the Pacific Ocean in Chile. It covers a total area of 40,600 mi2 (105,200 km2). Atacama Desert is famous as the driest place on Earth. Its annual average rainfall equals to 0- 0.08 in of water a year. Despite its harsh climate Atacama plants managed to survive in the region due to its unique adaptations.


Although the precipitation are extremely rare in the region and dryness is the most prominent characteristic of the Atacama Desert, some rare exceptions may occur. In July 2011, an extreme Antarctic cold front made its way to the Atacama desert, bringing 80 cm (31 in) of snow to the plateau. Many locals were caught by suprise. Many residents were stranded across the region, particularly in Bolivia, where many drivers became stuck in snow drifts and emergency crews became overwhelmed with a large number of rescue calls.




Its origin dates from about three million years ago, being in its past a seabed. Its change is related to the so-called Humboldt current. The main cause of the origin of the Atacama desert is a climatic phenomenon known as the Föhn effect, which causes the clouds to discharge their precipitations on a face of the mountain in its vertical ascent, so, when they exceed the mountain range, the clouds do not possess water, thus generating a desert by completely blocking all possible rainfall from the East, so it is the Andes that generates the Atacama desert, when the Foehn effect occurs on its slopes. In the west, rainfall over the Atacama desert is also blocked by stable high-pressure systems, known as "Pacific anticyclones," which remain along the coast, creating trade winds to the east that move storms.

On the other hand, the Humboldt current transports cold water from Antarctica10 northward along the Chilean and Peruvian coasts, which cools the western sea breezes, reduces evaporation and creates a thermal inversion — cold air immobilized below a layer of warm air—, preventing the formation of large rain-producing clouds. All the moisture created progressively by these sea breezes, condenses along the steep slopes of the Cordillera de la Costa that face the Pacific, creating highly endemic coastal ecosystems composed of cacti, succulents and other specimens of xerophilous flora.

The last factor that contributes to the desert formation is the Andes mountain range, which in the north forms an elevated and wide volcanic plain known as the Altiplano. Just as in the south, the Andean mountain range contributes to capture the humidity coming from the Pacific, in the north the Altiplano prevents the entry into Chile of storms loaded with moisture from the Amazon basin, which is located to the northeast.

In the Atacama desert, a rain that can be measured — that is, 1 mm or more — can take place once every 15 or 40 years — periods of up to 400 years have been recorded with no rainfall in its central sector— No However, the area is affected between January and February by the so-called «altiplanic winter», which produces occasional rain and abundant thunderstorms.

Contrary to conventional wisdom, it is not the driest desert in the world, this denomination corresponding to the dry valleys of McMurdo.

In the evenings the temperature fluctuates a lot, since it can go down to -25 ° C in the Ollagüe area, while in the day the temperature can be between 25 and 50 ° C in the shade. There is not much difference between summer and winter, because it is located on the edge of the Tropic of Capricorn. In summer, the morning ambient temperature is 4 to 10 ° C and the maximum can reach 45 ° C at full solar irradiation. Solar radiation is very high in the ultraviolet spectrum, so it is essential to use glasses and creams with UV protection.

The relative humidity of the air is only 18% in the interior, but very high on the coast, reaching up to 98% in the winter months. The atmospheric pressure is 1017 millibars. There are seasons of winds in tornado or blizzards whose speed can easily reach 100 km / h, generally recorded at noon.





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