DesertA desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the land surface of the Earth is arid or semi-arid. This includes much of the polar regions, where little precipitation occurs, and which are sometimes called polar deserts or "cold deserts".
ArizonaArizona (ˌærᵻˈzoʊnə ; Hoozdo Hahoodzo hoː˥z̥to˩ ha˩hoː˩tso˩; Alĭ ṣonak ˈaɭi̥ ˈʂɔnak) is a state in the Southwestern United States. It is the 6th-largest and the 14th-most-populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Four Corners region with Utah to the north, Colorado to the northeast, and New Mexico to the east; its other neighboring states are Nevada to the northwest, California to the west and the Mexican states of Sonora and Baja California to the south and southwest.
Sierra NevadaThe Sierra Nevada (siˌɛrə_nɪˈvædə,__ - nə'vædə -ˈvɑːdə) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily in Nevada. The Sierra Nevada is part of the American Cordillera, an almost continuous chain of mountain ranges that forms the western "backbone" of the Americas. The Sierra runs north-south and its width ranges from to across east–west.
Colorado RiverThe Colorado River (Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and in northern Mexico. The river drains an expansive, arid watershed that encompasses parts of seven U.S. states and two Mexican states. The name Colorado derives from the Spanish language for "colored reddish" due to its heavy silt load. Starting in the central Rocky Mountains of Colorado, it flows generally southwest across the Colorado Plateau and through the Grand Canyon before reaching Lake Mead on the Arizona–Nevada border, where it turns south toward the international border.
Rain shadowA rain shadow is an area of significantly reduced rainfall behind a mountainous region, on the side facing away from prevailing winds, known as its leeward side. Evaporated moisture from water bodies (such as oceans and large lakes) is carried by the prevailing onshore breezes towards the drier and hotter inland areas. When encountering elevated landforms, the moist air is driven upslope towards the peak, where it expands, cools, and its moisture condenses and starts to precipitate.
Bureau of Land ManagementThe Bureau of Land Management (BLM) is an agency within the United States Department of the Interior responsible for administering federal lands. Headquartered in Washington, D.C., and with oversight over , it governs one eighth of the country's landmass. President Harry S. Truman created the BLM in 1946 by combining two existing agencies: the General Land Office and the Grazing Service. The agency manages the federal government's nearly of subsurface mineral estate located beneath federal, state and private lands severed from their surface rights by the Homestead Act of 1862.
San Andreas FaultThe San Andreas Fault is a continental right-lateral strike-slip transform fault that extends roughly through the Californias. It forms the tectonic boundary between the Pacific Plate and the North American Plate. Traditionally, for scientific purposes, the fault has been classified into three main segments (northern, central, and southern), each with different characteristics and a different degree of earthquake risk. The average slip rate along the entire fault ranges from per year.
United StatesThe United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America and consisting of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations.
MonsoonA monsoon (mɒnˈsuːn) is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscillation of the Intertropical Convergence Zone (ITCZ) between its limits to the north and south of the equator. Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern, although technically there is also a dry phase.
Alluvial fanAn alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to semiarid climates, but are also found in more humid environments subject to intense rainfall and in areas of modern glaciation. They range in area from less than to almost . Alluvial fans typically form where flow emerges from a confined channel and is free to spread out and infiltrate the surface.
Bighorn sheepThe bighorn sheep (Ovis canadensis) is a species of sheep native to North America. It is named for its large horns. A pair of horns might weigh up to ; the sheep typically weigh up to . Recent genetic testing indicates three distinct subspecies of Ovis canadensis, one of which is endangered: O. c. sierrae. Sheep originally crossed to North America over the Bering Land Bridge from Siberia; the population in North America peaked in the millions, and the bighorn sheep entered into the mythology of Native Americans.
EndemismEndemism is the state of being a species found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be endemic to that particular part of the world. An endemic species can also be referred to as an endemism or in scientific literature as an endemite.
