Atacama Desert
South America’s Atacama Desert is dry. Only the cold desert, McMurdo dry valleys in Antarctica, is drier. Because the Andes mountains block rain from reaching the area it’s been a desert for just about 20 million years. Death Valley California has a reputation for being dry. But Atacama is 50 times as dry.
It’s not only the Andes keeping the Atacama Desert dry. The weather and other geographic features play a role. We won’t omit the Andes. The Andes Mountains’ rain shadow, the side downwind from prevailing winds, is the culprit here. On the opposite side moist air drops a great deal of rainfall. But that leaves the air dry as it tops the mountain and proceeds to the other side. As if the Andes aren’t enough, rain is blocked on the other side by the Chilean Coast Range. The anticyclone in the Pacific, a reverse spin area of very dry air, contributes on top of the rain shielding mountains.
Dry means dry. Rain falls in the Atacama Desert to the tune of only about 1 mm every year. Some areas never receive rain. There is also evidence that the entire region was completely rain free from about 1570 to 1971. Do you believe it’s dry? How can there be a drought were it barely rains in the first place? Some rivers there have been dry for over 120,000 years.
The super dry dry does lend the Atacama Desert some fame and fortune. Scientists have compared conditions there, including soil conditions, to conditions on Mars. In fact, it’s been a stand in for Mars in many movies including documentaries and fiction. In 2003 some scientists decided to conduct the same tests that the Mars landers, Viking 1 and Viking 2, had conducted on the red planet. These tests determined whether or not there was life on Mars. Can you guess the results? There were no signs of life in the Atacama Desert. Now this waterless desert is used for further research and even tests to prepare for future missions to Mars.
Whenever you need a drink, consider the Atacama Desert. There is no wet bar. In one of the driest places on Earth it could be years before you could even fill a small glass with water.
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