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What Is A Desert?

What is a desert?

A desert is an area that is very dry. It is the lack of moisture that truly defines a desert, not it's temperature or location. It is generally accepted that a desert must have less than 10 inches of precipitation in one year (1), however this is a loose definition and some consider other factors. Another definition for a desert is an area where the total evaporation is greater than the total precipitation.

All deserts have one thing in common...they're like toast without butter...dry.

They're like a mouthful of saltines...dry.

They're like British humor...dr.

They're like...well you get the idea.

For comparison, check out these cities annual rainfall (2)
Non-Deserts
Chicago: 35.1"
Los Angeles: 11.5"
London: 23.2"
Des Moines, IA: 31.9"
Deserts
Phoenix, AZ: 7.6"
Palm Desert, CA: 7.8"
Cairo, Egypt: 1.0"
Lima, Peru: 0.8"

You can see from the rainfall numbers above that some deserts are much drier than others. In fact, most deserts in the US are not as dry as others around the world.

Did You Know:
The Atacama Desert in Northern Chile is the driest place on earth (3). It receives 1 millimeter of rain (about .04" of rain) every 5 to 20 years. Some years it receives no rain at all!


(1) http://www.desertusa.com/glossary2.html

(2) http://www.worldclimate.com/

(3) http://www.nceas.ucsb.edu/nceas-web/kids/biomes/desert.htm