Deserts Of The Southwest
The four U.S deserts of Great Basin, Chihuahuan, Sonoran and Mojave are the known true deserts of the nation as each conforms to the encompassing definition of a desert which is a place where there is restricted plant life and very low rainfall. Among the four, the Great Basin desert is predominantly a cold desert due to its higher elevations and more northern latitude. The precipitation in the area, which measures at 7 to 12 inches a year, is more evenly distributed compared to the other three deserts. In the winter, this precipitation often falls as particles of snow.
Likewise, the other three deserts are hot for the most parts of the year and resemble a desert at a closer level with large areas showing sand and barren rocks, sparse grassland where many types of cactus grow, and very little plant life. Sonoran is the hottest desert in North America while Chihuahuan and Mojave are known as shrub desert and rainshadow desert respectively.
Great Basin Desert
When it comes to area, this desert measures the largest as it covers some parts of SE Idaho, most parts of west Utah, the southeast part of Oregon, a small part of NE California and most of Nevada. However, it doesn‚t cover some of the northern mountain ranges that border Idaho as well as the southernmost part that stretches up to 150 miles and are within the Mojave Desert.
Great Basin is characterized by thin, long and parallel mountain ridges that stretch from north to south and are separated by wider valleys which usually contain salt basins or dry lake beds. Some rivers flow inwards albeit lacking an outlet to the ocean. As a result, the waters would either evaporate or sink underneath the ground.
Situated in the south-eastern end point of California and SW Arizona, this desert is characterized by its huge flat plains and abundant cacti including the giant saguaro which grows most heavily in Arizona up to the higher elevated areas of the desert that reach between 1,500 and 3,500 feet.
The desert‚s western part, sometimes referred to as the “Colorado Desert,” is closer to where the Pacific storms originate. This area is noted for the breathtaking flowering of ephemerals at spring on the occurrence of a winter-spring rainfall.
Known as the second largest desert in the U.S., the Chihuahuan Desert extends a long stretch toward Mexico. It has elevations that are relatively higher compared to the ones found in the Sonoran Desert. Precipitation is also a bit greater with the rain falling mostly in the summer thunderstorm weather season. While cacti still abound, the dominant plants are agave and yucca while mesquite trees and creosote bushes are only seen in large areas.
This desert covers the southernmost part of Nevada by 150 miles, most of SE California, the lower elevated areas of NW Arizona and a small area of SW Utah. Its topography is relatively identical to the Great Basin due to the presence of isolated mountains and plains that are flat and wide. However, it also has less numerous hills, sparser vegetation and hotter temperatures.
The most recognizable plant found in the Mojave Desert is the Joshua tree which occurs only at elevations that are higher. Interestingly, it is also considered as an endemic plant in the area.