Delight in the Diversity of Deserts

There are myriad ways to classify a desert, but the simplest system figures into account the amount of precipitation that a given area gets. By precipitation, an arid desert receives less than eight inches of precipitation annually, while semiarid deserts receive eight to 20 inches. But precipitation is not the limiting factor in what defines a desert. Other factors include the number of days receiving precipitation, temperature, and humidity. Sometimes deserts are recognized by the wildlife adapted to dry desert climates.

The range of variation in desert types is broad. The classic hot desert, like the Sahara, occurs at equatorial latitudes. Cold deserts occur at higher latitudes, like those in the interior West. Polar deserts occur at the poles, where the cold air carries little moisture. For example, the thickest ice is the East Antarctic Ice Sheet, but the world’s coldest desert is along its border. The McMurdo Dry Valleys off of McMurdo Sound average less than 4 inches of precipitation per year—we’re guessing snow—with a mean annual temperature of -4 degrees. The Wright and Taylor valleys are ice-free, thanks to the surrounding mountains, and katabatic winds, cold air pulled earthward by the force of gravity at speeds up to 200 miles per hour, which evaporate any wayward ice or snow. Indeed, the Antarctic could be considered the world’s largest desert because the continent receives only 2 inches of precipitation on average per year.

The deserts of the western U.S. contain one of the hottest places in the world. Furnace Creek in Death Valley recorded one of the highest land temperatures in history at 134 degrees in 1914. Death Valley is one part of four true deserts in North America, the Great Basin, Sonoran, Mojave, and Chihuahuan deserts. The Great Basin is the largest desert in the U.S. at 190,000 square miles. Amid the dunes and dry river beds are uncountable desert adventures. Here are some of our favorites!