Shop Windows to the Universe

Young Voices for the Planet DVD in our online store includes 8 films where students speak out and take action on climate change.
This picture shows the Atacama Desert in Chile. The Atacama is one of the driest places on Earth. The average rainfall for a whole year in this desert is less than 1 millimeter (0.04 inch) per year!
Click on image for full size
Image courtesy of NASA.

Atacama Desert

The Atacama Desert is one of the driest places on Earth. The Atacama is in the country of Chile in South America. In an average year, much of this desert gets less than 1 millimeter (0.04 inch) of rain! That makes it 50 times drier than Death Valley in California.

It is hard to survive in the Atacama Desert. Few people, animals, plants, or even microbes live there. But the desert isn't completely without life. Some people and other living creatures do get by in the Atacama.

The north end of the Atacama Desert is near the border of Chile and Peru. It runs about 1,000 km (600 miles) south from there. It has an area of 140,000 km2 (54,000 square miles). That is about the size of the state of New York in the U.S.A.

The Atacama is the driest hot desert in the world. There are some weather stations in the Atacama where there has never been any rain! Not all deserts are hot. The Dry Valleys in Antarctica are cold deserts. They are the driest deserts on Earth.

Why is the Atacama so dry? First, this desert is located in the "rain shadow" between two mountain ranges, the Andes and the Chilean Coast Range. Second, winds called the Pacific Anticyclone flow through this area. Those winds blow dry air into the Atacama Desert. Third, another major flow of air in this region, the Walker circulation, causes air to descend near the Atacama. This descending air is very dry. Fourth, an ocean current called the Humboldt Current (or the Peru Current) carries cold water northward along the western coast of South America. This cold ocean current cools the air above it. Cold air can't hold as much water vapor as warm air so it dries out any water left in the air. This mix of mountains, winds, and ocean currents combines to make the Atacama incredibly dry.

The Atacama is also one of the oldest deserts in the world. Scientists think parts of it have been dry for at least 20 million years and maybe as long as 40 million years. That is much older than other very dry deserts. The Dry Valleys of Antarctica are about 10-11 million years old. The Namib Desert in Africa is only 5 million years old. Some dry river beds in the Atacama haven't had water flowing in them for 120,000 years!

Last modified October 27, 2008 by Randy Russell.

Shop Windows to the Universe Science Store!

Our online store includes issues of NESTA's quarterly journal, The Earth Scientist, full of classroom activities on different topics in Earth and space science, as well as books on science education!

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Extreme Environments

Extreme environments are places where "normal" life finds it hard to survive. That doesn't mean that there isn't any life in extreme environments. Certain creatures can live and grow in extreme environments....more

Life in the Atacama Desert

The Atacama Desert in Chile is one of the driest places on Earth. Some plants, animals, and microbes manage to survive there, though. People live and work in the Atacama Desert, too. Places like the Atacama,...more

The Desert Biome

Deserts are full of interesting questions. How can anything survive in a place with hardly any water? Why is it so dry to begin with? You can find at least one desert on every continent except Europe....more

Rain

Rain is precipitation that falls to the Earth in drops of 5mm or more in diameter according to the US National Weather Service. Virga is rain that evaporates before reaching the ground. Raindrops form...more

Rain Shadow

A rain shadow is a dry region of land on the side of a mountain range that is protected from the prevailing winds. Prevailing winds are the winds that occur most of the time in a particular location on...more

Winds in the Southeast Pacific

The winds in the Southeast Pacific mainly blow from south to north. They have a strong effect on the climate in the region and worldwide. The winds in this area get their start with a major flow in the...more

Walker Circulation

The Walker circulation is an ocean-based system of air circulation that influences weather on the Earth.  The Walker circulation is the result of a difference in surface pressure and temperature over the...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA