The Sonoran Desert is an arid region covering 120,000 square miles in southwestern Arizona and southeastern California, as well as most of Baja California and the western half of the state of Sonora, Mexico. Subdivisions of this hot, dry region include the Colorado and Yuma deserts. Irrigation has produced many fertile agricultural areas, including the Coachella and Imperial valleys of California. Warm winters attract tourists to Sonora Desert resorts in Palm Springs, California, and Tucson and Phoenix, Arizona.
This is the hottest of our North American deserts, but a distinctly bimodal rainfall pattern produces a high biological diversity. Winter storms from the Pacific nourish many West Coast annuals such as poppies and lupines, while well-developed summer monsoons host both annuals and woody plants originating from the south. Freezing conditions can be expected for a few nights in winter.
Trees are usually well developed on the desert ranges and their bajadas. Often abundant on these well-drained soils are Little-leaf Palo Verdes, Desert Ironwoods, Catclaw and Saguaro.
The understory consists of three, four or even five layers of smaller woody shrubs. Tall chollas may occur in an almost bewildering array of species. The alluvial lowlands host communities of Desert Saltbush, wolfberry and bursage. On coarser soils, Creosote Bush and bursage communities may stretch for miles. Where the water table is high, Honey or Velvet Mesquite may form dense bosques or woodlands.
Other species are restricted to alkaline areas. Stream sides may be lined with riparian woodlands composed of Arizona Ash, Arizona Black Walnut, Fremont Cottonwood and various willows, with a dense understory of Arrow-weed, Seepwillow and Carrizo. The Sonora Desert is rich in animal life as well, with many species in all groups derived from tropical and subtropical regions.
The western part of the Sonora Desert (sometimes called the "Colorado Desert") is closer to the source of Pacific storms and is noted for spectacular spring flowering of ephemerals when there is winter-spring rainfall. (This phenomenon is not limited to here.) However, the western portion is relatively depauperate, lacking many of the species such as the Saguaro that depend on good summer rainfall.
Approximate DesertUSA Boundaries: Bordered on the west by Borrego Springs, and San Gorgonio Pass in southern California, on the north by Interstate 10 in California and Interstate 40 in Arizona, on the east by Arizona's U.S. Route 191, south to the tip of Baja California, Mexico.
Some Parks and places of interest
Saguaro National Park
Organ Pipe Cactus National Monument
Lake Havasu State Park
Kartchner Caverns State Park
Picacho Peak State Park
Yuma Crossing SHP
Yuma Territorial Prison SHP
Arizona- Sonora Desert Museum
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The Saguaro Video
The Saguaro often begins life in the shelter of a "nurse" tree or shrub which can provide a shaded, moister habitat for the germination of life. The Saguaro grows very slowly -- perhaps an inch a year -- but to a great height, 15 to 50 feet.
Desert Food Chain Video
A food chain constitutes a complex network of organisms, from plants to animals, through which energy, derived from the sun, flows in the form of organic matter and dissipates in the form of waste heat.
Prickly pear cactus Video
Prickly pear cactus are found in all of the deserts of the American Southwest. Most prickly pears have large spines on their stems and vary in height from less than a foot to 6 or 7 feet.
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DesertUSA is a comprehensive resource about the North American deserts and Southwest destinations. Learn about desert biomes while you discover how desert plants and animals learn to adapt to the harsh desert environment. Find travel information about national parks, state parks, BLM land, and Southwest cities and towns located in or near the desert regions of the United States. Access maps and information about the Sonoran Desert, Mojave Desert, Great Basin Desert, and Chihuahuan Desert.