Mojave Desert

The Mojave Desert is a unique desert located in the Southwestern United States. It sits primarily in southeastern California and southwestern Nevada. Small portions of the desert also extend into Arizona and Utah. The Mojave is part of a larger North American desert system. This system includes the Sonoran, Chihuahuan, and Great Basin deserts. Of these four, the Mojave is the smallest and driest. It is often called the "high desert" because most of it sits at a high elevation.

The landscape follows a pattern called basin and range topography. This means the land consists of parallel mountain ranges and valleys. Large fans of sediment, known as bajadas, form around the mountains. These bajadas extend down toward low-altitude basins. Many basins contain playas, which are dried lake beds. Water collects in these playas and then evaporates. This process leaves behind large volumes of salt. Notable playas include Rogers Dry Lake and China Lake. The desert also contains the Devil's Playground. This area features dunes and salt flats stretching northwest to southeast.

The climate in the Mojave is characterized by extreme temperatures. In the summer, temperatures often rise above 100 degrees Fahrenheit. Winter brings freezing temperatures and strong winds. Most precipitation arrives from Pacific cyclonic storms. These storms migrate east from November to April. They often bring rain and snow to the mountains. This increases aridity on the leeward slopes. Late summer can also bring strong thunderstorms. These storms can cause heavy showers or cloudbursts. Such events can lead to sudden flash flooding.

The geology of the Mojave is very old and complex. Some rocks in the Death Valley region are at least 1700 million years old. These rocks were changed by intense heat and pressure. Much of the desert was once under shallow sea water. This created thick layers of conglomerate and mudstone. Long ago, the supercontinent Rodinia began to rift and thin. This allowed seawater to divide the landmass. Later, the Farallon Plate began to subduct under the North American Plate. This subduction created volcanoes and uplifting mountains. Around 16 million years ago, the crust began to stretch. This stretching created the Basin and Range province.

Death Valley is a major feature of this geological history. Between 240,000 and 10,000 years ago, large lakes filled the valleys. Lake Manly was the largest of these lakes. It filled Death Valley during each glacial period. About 10,500 years ago, these lakes were cut off from glacial melt. The lack of water caused the lakes to shrink. This concentrated salts and minerals in the basins. The modern desert environment formed after these lakes dried up. Death Valley remains the lowest elevation in North America.

The Mojave Desert supports diverse flora and fauna. The Joshua tree is an endemic species. This means it is found naturally only in this desert.

Other plants include the creosote bush and brittlebush. Many cacti live here, such as the silver cholla and Mojave prickly pear. The desert also features ironwood and blue Palo Verde. While the desert was historically resistant to fire, things are changing. Invasive annual plants like Bromus have created new fuel beds. These plants allow fires to spread more easily. This has significantly altered many desert areas.

Human activity is a significant part of the Mojave today. The desert is increasingly urbanized. Las Vegas is the largest urban area in the Mojave. It is also the largest urban area in Nevada. The Las Vegas metropolitan area has about 2.3 million people. Other cities include St. George, Utah, and the Lancaster-Palmdale area. The desert is also used for ranching and military training. Edwards Air Force Base is located in the California portion. The desert contains many mineral deposits. People have historically mined gold, silver, and tungsten here. Some ghost towns, like Calico, remain from the mining era.