Atacama Desert

One of the driest areas in the world is the Atacama Desert in South America. It’s the second driest desert in the world, after the McMurdo Dry Valleys of Antarctica. It’s been a desert for over 20 million years, kept that way by the Andes Mountains which block rain from reaching the area. Death Valley California has a reputation for being dry. But that area is 50 times wetter than the Atacama Desert.

Atacama Desert

It takes more than one mountain range to keep an area like the Atacama Desert so dry. The weather and other geographic features play a role. But let’s consider the 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 that’s not bad enough, the Chilean coast range is responsible for the same effect on the opposite side of the desert. Then there is the reverse spin dry air over the Pacific, it makes it worse.

The results are startling. 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. Is that a drought? How can there be a drought were it barely rains in the first place? There are even some riverbeds that haven’t held water for 120,000 years.

The Atacama Desert does gain some fame from its dry conditions. Scientists have compared conditions there, including soil conditions, to conditions on Mars. It’s a favorite location for movie makers when they want to film scenes that take place on Mars. In fact some of the same tests that were conducted on Mars were repeated in this desert in 2003. These tests determined whether or not there was life on Mars. Can you guess the results? Like Mars, the Atacama Desert had no life. Now this waterless desert is used for further research and even tests to prepare for future missions to Mars.

Atacama Desert

Whenever you need a drink, consider the Atacama Desert. There is no wet bar. The good news is you can’t pay for drinks that don’t exist.