The Driest Place on Earth - El Desierto de Atacama

I just spent a few days in the southern part of Chile's Atacama Desert, which stretches for about 650 miles to the Peruvian Border.

Although it borders the Pacific Ocean, the Atacama is generally considered the driest place on earth, as it is sandwiched between the rain shadows of the Andes to the east and the coast ranges to the west. The cold Humboldt Current off the coast, which suppresses evaporation from the ocean, does not serve to enhance moisture for precipitation. As an old "desert rat", I was in hog heaven. Since it was winter, the temperature was quite pleasant. I would not want to have been here in January.

And dry? There are places in the Atacama where there has been no recorded or observed rainfall in the 400+ years since the Spaniards first arrived.

Some of the landscapes reminded me of the Sinai and parts of Nevada, Utah, New Mexico, and Arizona. Quite spectacular!

I lectured at the branch of Universidad Santo Tomas ((UST) in Copiapo, a regional governmental, mining, and agricultural center (much of the USA's winter red table grapes come from this area) about 500 miles (800 km) north of Santiago. Copiapo (population: about 150,000) is one of the Atacama's "wetter" places;  the locals told me they last had rainfall (twice!) in 1997 - a whopping 60 mm (2.4 inches) in one day, and then another 50 mm (2 inches) the next month. The long-term annual average (meaningless, really) is 10 mm or 0.4 inches. There is surface water there, as the Rio Copiapo flows at times with snowmelt from the higher elevations.

Mining (copper, especially) is big in the Atacama, and there are issues with water depletion and pollution. That was of concern to the locals, so I switched my lecture from climate change in the Western USA to water conflict management. They were very appreciative. I'm not sure climate change would have been too relevant ("Hey, you're going to be warmer and drier!").

Some interesting comparisons have been made to the lunar landscapes and those of the Atacama. More fascinating is the similarity between the "soils" of the Atacama and those of Mars. Here is a link to an interesting article in Astrobiology magazine about the lack of biological activity in the Atacama's "soil" versus the Martian "soil" when the techniques used in the 1976 Viking Martian lander were employed. Had Viking landed in the Atacama, it would have obtained the same results it found on Mars. Keep in mind that more sophisticated techniques have detected microbes in the Atacama's soil. But it is an interesting view on the dry limit of life.

I think Woody Hayes' classic quote is apropos - perhaps he had the Atacama's rainfall data in mind.

"Statistics reminds me of the man who drowned in a river whose average depth was only three feet." -- Woody Hayes

Comments

[Michael]

Some streams flow because of snowmelt from the Andes, and there is a lot of (unsustainable) ground water pumping.

[loonitic]

how do people there survive?