South America’s Atacama Desert is dry. It’s the second driest desert in the world, after the McMurdo Dry Valleys of Antarctica. Because the Andes mountains block rain from reaching the area it’s been a desert for just about 20 million years. A lot of people consider death Valley California the height of dry desert. However, Death Valley is 50 times wetter than the Atacama Desert.
It takes more than just one mountain range to maintain the amazing Atacama Desert. A number of land features and weather factors converge in this unique location. The first, of course, is those Andes. The Andes Mountains’ rain shadow, the side downwind from prevailing winds, is the culprit here. This means that when winds and moist air hit the mountain on one side, that air condenses into a lot of rain. But the air is bone dry when it tops the mountain. As if the Andes aren’t enough, rain is blocked on the other side by the Chilean Coast Range. Then there is the reverse spin dry air over the Pacific, it makes it worse.
Dry means dry. There is only about 1 mm of rain per year in the Atacama Desert. Some areas never receive rain. Meteorologists also believe that a complete drought, no rain at all, began in 1570 and lasted 400 years. Any questions? Is it even possible to have a drought where rain hardly ever falls 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. Many movies and documentaries about Mars have been filmed in this desert. In fact some of the same tests that were conducted on Mars were repeated in this desert in 2003. The tests were created to search for life. What did they find? Like Mars, the Atacama Desert had no life. As a result, the desert is used as a testing ground for methods of further examining Mars.
Next time you’re thirsty, consider life in the Atacama Desert. Drinks are not served there. 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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