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107-936: The North American monsoon , variously known as the Southwest monsoon , the Mexican monsoon , the New Mexican monsoon , or the Arizona monsoon is a term for a pattern of pronounced increase in thunderstorms and rainfall over large areas of the southwestern United States and northwestern Mexico . Geographically, the weather pattern is centered over the Sierra Madre Occidental in the Mexican states of Sinaloa , Durango , Sonora and Chihuahua , and typically occurs between June and mid-September. Thunderstorms are fueled by daytime heating and build up during

214-412: A form of inverted trough that shares many characteristics of a tropical wave. A tropical wave normally follows an area of sinking, intensely dry air, blowing from the northeast . After the passage of the trough line, the wind veers southeast, the humidity abruptly rises, and the atmosphere destabilizes . This yields widespread showers and thunderstorms , sometimes severe . As the wave moves westward,

321-544: A large oasis at the western end of the El Paso-Tucson corridor. The region between the two cities is a major transportation trunk with settlements serving both highway and railway needs. There are also large mining operations, ranches, and agricultural oases. Both El Paso and Tucson have large military installations nearby; Fort Bliss and White Sands Missile Range north of El Paso in New Mexico, and, near Tucson,

428-595: A settlement in Arizona in 1599, but were turned back by inclement weather. In 1610, Santa Fe was founded, making it the oldest capital in United States. In 1664 Juan Archuleta led an expedition into what is now Colorado, becoming the first European to enter. A second Spanish expedition was led into Colorado by Juan Ulibarrí in 1706, during which he claimed the Colorado territory for Spain. From 1687 to 1691

535-458: A sub-region of the South , which some consider southwestern in the general framework of the original application, meaning the "Western South." This is an area containing the basic elements of Southern history , culture , politics , religion , and linguistic and settlement patterns, yet blended with traits of the frontier West. While this particular Southwest is notably different in many ways from

642-552: A third of Colorado, and small portions of Kansas, Oklahoma, and Wyoming. Texas current borders were set in the Compromise of 1850 , where Texas ceded land to the federal government in exchange for $ 10 million, which would go to paying off the debt Texas had accumulated in its war with Mexico. Following the Mexican Cession, the lands of what had been the Mexican territory of Alta California were in flux: portions of what

749-418: A tropical wave. This normally occurs if upper-level wind shear is too strong. The storm can redevelop if the upper-level shear abates. If a tropical wave is moving quickly, or is organized enough, it can have winds of a strength in excess of tropical storm force, but it is not considered a tropical storm unless it has a closed low-level circulation. An example of this was Hurricane Claudette in 2003 , where

856-435: Is a serious danger during the monsoon. Dry washes can become raging rivers in an instant, even when no storms are visible as a storm can cause a flash flood tens of miles away. Lightning strikes are also a significant danger. Because it is dangerous to be caught in the open when these storms suddenly appear, many golf courses in Arizona have thunderstorm warning systems. In Albuquerque , flash flooding from storms funneled into

963-838: Is bordered to the south by the Mogollon Rim and the Sonoran Desert, to the west by the Mojave Desert, and to the east by the Rocky Mountains , the Rio Grande Rift valley, and the Llano Estacado . The Plateau is characterized by a series of plateaus and mesas, interspersed with canyons. The most dramatic example is the Grand Canyon . But that is one of many dramatic vistas included within

1070-609: Is from the Mojave Desert in California in the west (117° west longitude) to Carlsbad, New Mexico , in the east (104° west longitude); another says that it extends from the Mexico–United States border in the south to the southern areas of Colorado, Utah, and Nevada in the north (39° north latitude). In another definition, the core Southwestern U.S. includes only the states of Arizona and New Mexico; others focus on

1177-601: Is more substantial if the dryline which separates the hot and dry airmass to the Northwest from the humid monsoon airmass to the Southeast, fails to migrate. This can prevent tropical moisture from reaching farther Northwest towards Death Valley until later in the summer. If this pattern prevails, the Nevada deserts may receive almost no monsoon. In early summer, the monsoon starts with a shift in wind patterns as Mexico and

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1284-542: Is now New Mexico were claimed, but never controlled, by Texas. With the Compromise of 1850, the states of Texas and California were created (Texas as a slave state, and California as a free state), as well as the Utah Territory and New Mexico Territory . The New Mexico Territory consisted of most of Arizona and New Mexico (excluding a strip along their southern borders), a small section of southern Colorado, and

1391-704: Is the saguaro cactus , which is unique to the desert. It is bounded on the northwest by the Mojave Desert, to the north by the Colorado Plateau and to the east by the Arizona Mountains forests and the Chihuahuan Desert. Aside from the trademark saguaro, the desert has the most diverse plant life of any desert in the world, and includes many other species of cacti, including the organ-pipe, senita, prickly pear, barrel, fishhook, hedgehog, cholla, silver dollar, and jojoba. The portion of

1498-405: Is the smallest, driest and hottest desert within the United States. The Mojave gets less than 6 in (150 mm) of rain annually, and its elevation ranges from 3,000 to 6,000 feet (900 to 1,800 meters) above sea level. The most prolific vegetation is the tall Joshua tree , which grow as tall as 40 ft (12 m), and are thought to live almost 1000 years. Other major vegetation includes

1605-630: The American Southwest or simply the Southwest , is a geographic and cultural region of the United States that includes Arizona and New Mexico , along with adjacent portions of California , Colorado , Nevada , Oklahoma , Texas , and Utah . The largest cities by metropolitan area are Phoenix , Las Vegas , El Paso , Albuquerque , and Tucson . Before 1848, in the historical region of Santa Fe de Nuevo México as well as parts of Alta California and Coahuila y Tejas , settlement

1712-713: The Ancestral Pueblo people , the Hohokam , and the Mogollon , all of which existed among other surrounding cultures including the Patayan . Maize began to be cultivated in the region sometime during the early first millennium BC, but it took several hundred years for the native cultures to be dependent on it as a food source. As their dependence on maize grew, Pre-Columbian Indians began developing irrigation systems around 600 CE . According to archeological finds,

1819-624: The Arizona Organic Act , which officially created the U.S. Territory of Arizona , splitting the New Mexico Territory at the 107th meridian. Utah, as shown above, evolved out of the Utah Territory, as pieces of the original territory created in 1850 were carved out: parts were ceded to Nevada, Wyoming, and Colorado in 1861; another section to Nevada in 1862; and the final section to Nevada in 1866. In 1890,

1926-557: The Davis-Monthan Air Force Base . About 70 miles (110 km) to the southeast are the research facilities at Fort Huachuca . These military installations form a kind of hinterland around the El Paso-Tucson region, and are served by scientific and residential communities such as Sierra Vista , Las Cruces , and Alamogordo . El Paso's influence extends north into the Mesilla Valley , and southeast along

2033-592: The Gadsden Purchase in 1853. In 1851, San Luis became the first European settlement in what is now Colorado. Of the states of which at least a portion make up the Southwest, Texas was the first to achieve statehood. On December 29, 1845, the Republic of Texas was annexed, bypassing the status of becoming a territory, and immediately became a state. Initially, its borders included parts of what would become several other states: almost half of New Mexico,

2140-733: The Gulf of California (and to lesser extent the eastern Pacific and Gulf of Mexico ) over northwestern Mexico and southwestern US resulting in summer thunderstorms, especially at higher elevations. The North American monsoon is not as strong or persistent as its Indian counterpart , mainly because the Mexican Plateau is not as high or as large as the Tibetan Plateau in Asia. However, the North American monsoon shares most of

2247-555: The Gulf of California and eastern Pacific . The Gulf of California, a narrow body of water surrounded by mountains, is particularly important for low-level moisture transport into Arizona and Sonora . Upper level moisture is also transported into the region, mainly from the Gulf of Mexico by easterly winds aloft. Once the forests of the Sierra Madre Occidental green up from the initial monsoon rains, evaporation and plant transpiration can add additional moisture to

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2354-677: The Narváez expedition (1528–36) who had crossed eastern Texas on their way to Mexico City, led an expedition to discover the Seven Golden Cities of Cíbola. The 1582–3 expedition of Antonio de Espejo explored New Mexico and eastern Arizona; and this led to Juan de Oñate 's establishment of the Spanish province of Santa Fe de Nuevo México in 1598, with a capital founded near Ohkay Oweenge Pueblo , which he called San Juan de los Caballeros. Oñate's party also attempted to establish

2461-532: The Phoenix metropolitan area . The city of Phoenix is the largest urban center, and located in the approximate center of the area that includes Tempe , Mesa , and many others. Meinig calls the third subregion "El Paso, Tucson, and the Southern Borderlands." While El Paso and Tucson are distinctly different cities, they serve as anchor points to the hinterland between them. Tucson occupies

2568-676: The Rio Grande Valley by the Sandia-Manzano mountain range has prompted the city to develop an extensive system of concrete-lined arroyos and retention structures, similar to the flood control channels in the Los Angeles River basin. Once the monsoon is underway, mountain ranges, including the Sierra Madre Occidental , the Mogollon Rim , and the Rio Grande Rift ranges provide a focusing mechanism for

2675-553: The San Luis Valley of southern Colorado to south of Socorro and including the Sandia-Manzano Mountains , with an east–west breadth in the north stretching from the upper Canadian River to the upper San Juan River . The area around Albuquerque is sometimes called Central New Mexico . "Central Arizona" is a vast metropolitan area spread across one contiguous sprawling oasis, essentially equivalent to

2782-556: The 1930s and 1940s, many definitions of the Southwest included all or part of Texas, Oklahoma, New Mexico, Arizona, California, Colorado, and Utah. As time has gone on, the definition of the Southwest has become more solidified and more compact. For example, in 1948 the National Geographic Society defined the American Southwest as all of California, Nevada, Utah, Arizona, Colorado, and New Mexico, and

2889-477: The American Southwest as parts of Arizona, Colorado, Kansas, New Mexico, Oklahoma, Texas, and Utah. From this perspective, almost all of the region's physiographical traits, geological formations, and weather are contained within a box between 26° and 38° northern latitude, and 98° 30' and 124° western longitude. When looking at the fauna of the region, there is a broader definition of the American Southwest. The Southwestern Center for Herpetological Research defines

2996-539: The American Southwest, leading to below average rainfall. Whether the North American Monsoon (NAM) is a "true monsoon" has been controversial. Until the late 1970s, there was serious debate about whether a monsoon truly existed in North America. However, according to NOAA, considerable research culminating in 1993 established the fact that that a summer monsoon develops over much of Mexico and

3103-471: The Ancestral Pueblo people, also known as the "Anasazi" (although that term is viewed by modern Pueblo people as derogatory and is becoming more and more disused), began settling in the area in approximately 1500 BC. Eventually, they would spread throughout the entire northern section of the Southwest. This culture would go through several different eras lasting from approximately 1500 BC through

3210-672: The Ancestral Puebloans, while the Akimel O'odham and Tohono O'odham claim descent from Hohokam. The area previously occupied by the Mogollon was taken over by an unrelated tribe, the Apache . While it is unclear whether any of the modern Indian tribes are descended from the Mogollon, some archeologists and historians believe that they mixed with Ancestral Puebloans and became part of the modern Hopi and Zuni tribes. Prior to

3317-826: The Canyonlands section just to its north; the Navajo section is bordered to the south by the Grand Canyon section, which of course is dominated by the Grand Canyon; and the southeasternmost portion of the Plateau is the Datil section, consisting of valleys, mesas, and volcanic formations. Albuquerque is the most populous city often considered at the edge of this portion contained in the Southwest region, but Santa Fe, New Mexico and Flagstaff, Arizona, are also significant population centers. Phoenix , Tucson, and Las Vegas dominate

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3424-719: The City of Tucson was founded when the Presidio San Augustin del Tucson was created, relocating the presidio from Tubac. In 1776, two Franciscan priests, Francisco Atanasio Domínguez and Silvestre Vélez de Escalante, led an expedition from Santa Fe heading to California. After passing through Colorado, they became the first Europeans to travel into what is now Utah. Their journey was halted by bad weather in October, and they turned back, heading south into Arizona before turning east back to Santa Fe. In 1804 Spain divided

3531-650: The Exploration of the Columbia River of the West and Its Tributaries , which was later republished as The Exploration of the Colorado River and Its Canyons . In 1877 silver was discovered in southeastern Arizona. The notorious mining town of Tombstone, Arizona was born to service the miners. The town would become immortalized as the scene of what is considered the greatest gunfight in the history of

3638-656: The Jesuit priest Eusebio Kino established several missions in the Santa Cruz River valley; and Kino further explored southern and central Arizona in 1694, during which he discovered the ruins of Casa Grande. Beginning in 1732, Spanish settlers began to enter the region, and the Spanish started bestowing land grants in Mexico and the Southwest US. In 1751, the O'odham rebelled against the Spanish incursions, but

3745-538: The LDS church issued the 1890 Manifesto , which officially banned polygamy for members of the church. It was the last roadblock for Utah entering the Union, and on January 4, 1896, Utah was officially granted statehood, becoming the 45th state. In 1869, John Wesley Powell led a 3-month expedition which explored the Grand Canyon and the Colorado River. In 1875, he would publish a book describing his explorations, Report of

3852-774: The Mojave Desert. Bordered on the south by the Sonoran Desert and the east by the Colorado Plateau, its range within the region makes up the southeast tip of Nevada, the southwestern corner of Utah and the northwestern corner of Arizona. In terms of topography, the Mojave is very similar to the Great Basin Desert, which lies just to its north. Within the region, Las Vegas is the most populous city; other significant population centers include Laughlin and Pahrump in Nevada, St. George and Hurricane in Utah, and Lake Havasu City , Kingman , and Bullhead City in Arizona. The Mojave

3959-491: The Mojave and Colorado deserts in California. Other individuals who focus on Southwest studies who favored a more limited extent of the area to center on Arizona and New Mexico, with small parts of surrounding areas, include Erna Fergusson , Charles Lummis (who claimed to have coined the term, the Southwest), and cultural geographer Raymond Gastil , and ethnologist Miguel León-Portilla . Geographer D. W. Meinig defines

4066-680: The Native American (especially Apache , Pueblo , and Navajo ), Hispano , Mexican American , and frontier cowboy . The geography of the region is mainly made up of four features: the Mojave , Sonoran , and Chihuahuan Deserts , and the Colorado Plateau ; although there are other geographical features as well, such as a portion of the Great Basin Desert . The deserts dominate the southern and western reaches of

4173-407: The Nevada deserts may receive almost no monsoon influence if the western subtropical high shifts less than in typical years. For instance in 2020, the subtropical high remained further south than usual due to the influence of a strong ridge of high pressure over the northern Pacific, displacing the jet stream further inland. The combination of these factors blocked moist tropical air from reaching

4280-538: The Old West, the Gunfight at the O.K. Corral . Copper was also discovered in 1877, near Bisbee and Jerome in Arizona, which became an important component of the economy of the Southwest. Production began in 1880 and was made more profitable by the expansion of the railroad throughout the territory during the 1880s. The early 1880s also saw the completion of the second transcontinental railroad, which ran through

4387-510: The Parry saltbush and the Mojave sage, both only found in the Mojave, as well as the creosote bush. The Colorado Plateau varies from the large stands of forests in the west, including the largest stand of ponderosa pine trees in the world, to the Mesas to the east. Although not called a desert, the Colorado Plateau is mostly made up of high desert. Within the Southwest U.S. region, the Colorado

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4494-471: The Pecos, north of the [Mexican] Border, south of the Mesa Verde and the Grand Canyon, and east of the mountains which wall off Southern California and make it a land in itself." Texas has long been the focal point of this dichotomy, and is often considered, as such, the core area of "the South's Southwest." While the Trans-Pecos area is generally acknowledged as part of the desert Southwest , most of Texas and large parts of Oklahoma are often placed into

4601-466: The Plateau, which includes spectacular lava formations, "painted" deserts, sand dunes, and badlands. One of the most distinctive features of the Plateau is its longevity, having come into existence at least 500 million years ago. The Plateau can be divided into six sections, three of which fall into the Southwest region. Beginning with the Navajo section forming the northern boundary of the Southwestern United States, which has shallower canyons than those in

4708-427: The Provincia de las Californias, creating the province Alta California , which consisted primarily of what would become California, Nevada, Arizona, Colorado, Utah and New Mexico. In 1821 Mexico achieved its independence from Spain and shortly after, in 1824, developed its constitution , which established the Alta California territory, which was the same geographic area as the earlier Spanish province. In 1825, Arizona

4815-404: The Rio Grande into the Trans-Pecos region of Texas. The fourth subregion Meinig calls the "Northern Corridor and Navajolands," a major highway and railway trunk which connects Albuquerque and Flagstaff . Just north of the transportation trunk are large blocks of American Indian land. As the US expanded westward , the country's western border also shifted westward, and consequently, so did

4922-411: The Sonora Desert which lies in the Southwestern United States is the most populated area within the region. Six of the top ten major population centers of the region are found within its borders: Phoenix, Tucson , Mesa , Chandler , Glendale , and Scottsdale , all in Arizona. Also within its borders are Yuma and Prescott, Arizona . The most northwest portion of the American Southwest is covered by

5029-405: The Sonoran Desert to the west. The Chihuahuan Desert spreads across the southeastern portion of the region, covering from southeastern Arizona, across southern New Mexico, and the portion of western Texas included in the Southwest. While it is the second largest desert in the United States, only a third of the desert is within the United States, with the rest in Mexico. El Paso and Albuquerque are

5136-410: The Southwest as being only the states of Arizona, New Mexico, with parts of California, Nevada, Texas, and Utah; although they include all of those six states in their map of the region, solely for ease of defining the border. Lawrence Clark Powell, a major bibliographer whose emphasis is on the Southwest, defined the American Southwest in a 1958 Arizona Highways article as, "the lands lying west of

5243-411: The Southwest became embroiled in the Mexican–American War , partly as a result of the United States' annexation of Texas. On August 18, 1846, an American force captured Santa Fe, New Mexico. On December 16 of the same year, American forces captured Tucson, Arizona, marking the end of hostilities in the Southwest United States. When the war ended with the Treaty of Guadalupe Hidalgo on February 2, 1848,

5350-407: The Southwest began to decline for unknown reasons, although severe drought and encroachment from other peoples have been postulated. By the end of the 15th century, all three cultures had disappeared. The modern Puebloan tribes of the Isleta , Sandia , Cochiti , Kewa , Santa Ana , Taos , Jemez , Acoma , Laguna , and Zia , as well as the Hopi and Zuni peoples , trace their ancestry back to

5457-494: The Southwest in a very similar fashion to Reed: the portion of New Mexico west of the Llano Estacado and the portion of Arizona east of the Mojave - Sonoran Desert and south of the "canyon lands" and also including the El Paso district of western Texas and the southernmost part of Colorado. Meinig breaks the Southwest down into four distinct subregions. He calls the first subregion " Northern New Mexico ," and describes it as focused on Albuquerque and Santa Fe . It extends from

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5564-494: The Southwest. Around AD 1100 their culture began to develop in the Four Corners area of the region. The Navajos migrated from northwestern Canada and eastern Alaska , where the majority of Athabaskan speakers reside. The Ute were found over most of modern-day Utah and Colorado, as well as northern New Mexico and Arizona. The Paiutes roamed an area which covered over 45,000 square miles of southern Nevada and California, south-central Utah, and northern Arizona. The Hopi settled

5671-446: The United States gained control of all of present-day California, Nevada and Utah, as well as the majority of Arizona, and parts of New Mexico and Colorado (the rest of present-day Colorado, and most of New Mexico had been gained by the United States in their annexation of the Republic of Texas). The final portion of the Southwestern United States came about through the acquisition of the southernmost parts of Arizona and New Mexico through

5778-565: The ancestral Puebloans. The modern-day Zuni established a culture along the Zuni River in far-eastern Arizona and western New Mexico. Both major tribes of the O'odham tribe settled in the southern and central Arizona, in the lands once controlled by their ancestors, the Hohokam. The first European intrusion into the region came from the south. In 1539, a Jesuit Franciscan named Marcos de Niza led an expedition from Mexico City which passed through eastern Arizona. The following year Francisco Vázquez de Coronado , based on reports from survivors of

5885-414: The area, namely the Animas , San Andres , and Doña Ana Mountains in New Mexico; and the Franklin , Hueco , and Davis Mountains in Texas. It also reaches up into the foothills of the higher ranges such as the Black Range and Oscura Mountains in New Mexico. High above the desert, these forest-covered and sometimes snow-capped mountains form sky islands , with radically different flora and fauna than

5992-408: The area, while the plateau (which is largely made up of high desert) is the main feature north of the Mogollon Rim . The two major rivers of the region are the Colorado River , running in the northern and western areas, and the Rio Grande , running in the east, north to south. Formed approximately 8000 years ago, the Chihuahuan Desert is a relatively dry desert, although it is slightly wetter than

6099-420: The area. The Chihuahuan Desert is considered the "most biologically diverse desert in the Western Hemisphere and one of the most diverse in the world," and includes more species of cacti than any other desert in the world. The most prolific plants in this region are agave , yucca and creosote bushes , in addition to the ubiquitous presence of various cacti species. When people think of the desert southwest,

6206-403: The arrival of Europeans, the Southwestern United States was inhabited by a very large population of American Indian tribes. The area once occupied by the ancestral Puebloans became inhabited by several American Indian tribes, the most populous of which were the Navajo , Ute , Southern Paiute , and Hopi. The Navajo, along with the Hopi, were the earliest of the modern Indian tribes to develop in

6313-400: The atmosphere which will then flow into Arizona and New Mexico. Finally, if the southern Plains of the U.S. are unusually wet and green during the early summer months, that area can also serve as a moisture source. As precipitable water values rise in early summer, brief but often torrential thunderstorms can occur, especially over mountainous terrain. This activity is occasionally enhanced by

6420-507: The atmosphere; nevertheless, local topographic effects are critical to the geographic and even temporal distribution of convective activity. The monsoon ridge is almost as strong as the one which develops over Asia during the summer. However, since the lower level moisture flow is not as persistent as in the Indian monsoon , the upper level steering pattern and disturbances around the ridge are critical for influencing where thunderstorms develop on any given day. The exact strength and position of

6527-449: The basic characteristics of its Indian counterpart. In the monsoon area, the late spring period is very hot and dry, because the dry western side subtropical high pressure ridge and dry continental air have not begun to 'shift' northwards yet. During this period, inland areas have extremely low relative humidity, and characteristically very low dew points , which are frequently well below the freezing mark. In some years, this delayed effect

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6634-434: The classic "Old South" or Southeast , these features are strong enough to give it a separate southwestern identity quite different in nature from that of the interior southwestern states to the west. Tropical waves West-moving waves can also form from the tail end of frontal zones in the subtropics and tropics, and may be referred to as easterly waves, but the waves are not properly called tropical waves. They are

6741-457: The command of Lt. Colonel John Robert Baylor forced the surrender of the small Union garrison stationed at Fort Fillmore , near Mesilla, New Mexico . On August 1, 1861, Baylor declared the creation of the Arizona Territory , and claimed it for the Confederacy, with Mesilla as its capital. The territory, which had been formed by the portion of the existing New Mexico Territory below the 34th parallel, became official on February 14, 1862. Nevada

6848-423: The complex interactions between atmospheric circulation features at both the synoptic (100 to 1000 km spatially, 1 day to 1 week, temporally) and mesoscale (several km to 100 km, hours to one day temporally) and the extremely varied topography. The larger-scale atmospheric motions may control the distribution of water vapor and the general stability or instability (that is, the tendency to form storms) in

6955-568: The continent into the Atlantic Ocean . These are generated or enhanced by the African Easterly Jet . The clockwise circulation of the large transoceanic high-pressure cell or anticyclone centered near the Azores islands (known as the Azores High ) impels easterly waves away from the coastal areas of Africa towards North America . Tropical waves are the origin of approximately 60% of Atlantic tropical cyclones and of approximately 85% of intense Atlantic hurricanes ( Category 3 and greater). Tropical cyclones can sometimes degenerate back into

7062-482: The daily development of thunderstorms. Thus much of the monsoon rainfall occurs in mountainous terrain. For example, monsoon rainfall in the Sierra Madre Occidental typically ranges from 10 to 15 inches. Since the southwest U.S. is at the northern fringe of the monsoon, precipitation is less and tends to be more variable. Areas farther west of the core monsoon region, namely California and Baja California, typically receive only spotty monsoon-related rainfall. In those areas,

7169-479: The establishment of Alta Ski Area , Utah's skiing began to be developed. Due to the ski conditions in the state, during WWII, the 10th Mountain Division established Camp Hale in Colorado to train elite ski troops. While this article deals with the core definition for the American Southwest, there are many others. The various definitions can be broken down into four main categories: Historical/Archeological; Geological/Topographical; Ecological; and Cultural. In

7276-415: The heart of the Southwest, called the "Santa Fe Route." It ran from Chicago, down through Topeka, then further south to Albuquerque, before heading almost due west through northern Arizona to Los Angeles. The repeal of the Sherman Silver Purchase Act in 1893 led to the decline of the silver mining industry in the region. In 1901, the Santa Fe Railroad reached the South Rim of the Grand Canyon, opening

7383-428: The intense solar heating is not strong enough to overcome a continual supply of cold water from the North Pacific Ocean moving down the west coast of North America . Winds do turn toward the land in these areas, but the cool moist air actually stabilizes the atmosphere. The monsoon pushes as far west as the Peninsular Ranges and Transverse Ranges of Southern California, but rarely reaches the coastal strip. As shown in

7490-452: The intermountain region of the U.S. The controversy continues in part because of the incomplete reversal of the winds during the NAM. The prevailing winds shift from westerly before to southerly during the NAM. Because this is not a complete 180-degree reversal, some climatologists claim the weather pattern is not a true monsoon. Other climatologists disagree. Southwestern United States The Southwestern United States , also known as

7597-428: The land within the old Spanish and Mexican borders of the Nuevo México Province or the later American New Mexico Territory . Distinct elements of the Western lifestyle thrive in the region, such as Western wear and Southwestern cuisines , including Native American , New Mexican , and Tex-Mex , or various genres of Western music like Indigenous , New Mexico , and Tejano music styles. Likewise with

7704-708: The lands of the central and western portions of northern Arizona. Their village of Oraibi , settled in approximately AD 1100, is, along with Acoma Sky City in New Mexico, one of the oldest continuously occupied settlements in the United States. The Mogollon area became occupied by the Apaches and the Zuni. The Apache migrated into the American Southwest from the northern areas of North America at some point between 1200 and 1500. They settled throughout New Mexico, eastern Arizona, northern Mexico, parts of western Texas, and southern Colorado. The Zuni count their direct ancestry through

7811-413: The landscape of the Sonoran Desert is what mostly comes to mind. The Sonoran Desert makes up the southwestern portion of the Southwest; most of the desert lies in Mexico, but its United States component lies on the southeastern border of California, and the western 2/3 of southern Arizona. Rainfall averages between 4 and 12 in (100 and 300 mm) per year, and the desert's most widely known inhabitant

7918-407: The last of the 48 contiguous United States on February 14, 1912. The 1930s saw the beginning of the ski industry in the Southwest. Resorts were established in Colorado in areas such as Estes Park , Gunnison , and on Loveland Pass . New Mexico's oldest ski area is Sandia Peak Ski Area at the eastern edge of Albuquerque , which opened to skiers in 1936. At the end of the decade, in 1939, with

8025-432: The late afternoon and early evening. Typically, these storms dissipate by late night, and the next day starts out fair, with the cycle repeating daily. The cycle typically loses its energy by mid-September when much drier conditions are reestablished over the region. Whether the North American monsoon is a true monsoon remains controversial. The North American monsoon is a complex weather process that brings moisture from

8132-803: The location of the Southwestern and Northwestern United States . In the early years of the United States, newly colonized lands lying immediately west of the Appalachian Mountains were detached from North Carolina and given the name Southwest Territory . During the decades that followed, the region known as "the Southwestern United States" covered much of the Deep South east of the Mississippi River. However, as territories and eventual states to

8239-676: The major US cities in this desert, with other smaller cities being Las Cruces and Roswell in New Mexico and Willcox in Arizona. The elevation in the Chihuahuan varies from about 1,750 to 6,000 feet (500 to 1,800 meters), as there are several larger mountain ranges, such as the Organ Mountains , the Guadalupe Mountains , and the Chiracahua Mountains , plus many smaller mountain ranges contained in

8346-709: The middle of the 15th century AD: the Basketmaker I , II , and III phases followed by the Pueblo I , II , III , and IV . As the Puebloans transitioned from a nomadic lifestyle to one based on both dry land and irrigated agriculture, their first domiciles were pithouses. The Mogollon culture developed later than the Puebloan, arising in the eastern area of the region at around 300 BC. Their range would eventually extend deep into what would become Mexico, and dominate

8453-600: The monsoon or subtropical ridge , develops in the upper atmosphere over the Four Corners region, creating wind flow aloft from the east or southeast. At the same time, a thermal low (a trough of low pressure from intense surface heating) develops over the Mexican Plateau and the Desert Southwest of the United States. The thermal low sets up circulation that brings pulses of low level moisture from

8560-708: The monsoons, the Sonoran and Mojave are considered relatively "wet" when ranked among other deserts such as the Sahara , and helps fuel the Chihuahuan Desert 's extreme diversity. Monsoons often play a role in reducing wildfire threats by providing moisture at higher elevations during the wildfire season. Heavy monsoon rain can lead to excess winter plant growth, in turn a summer wildfire risk. A lack of monsoon rain can hamper summer seeding, reducing excess winter plant growth but worsening drought. Flash flooding

8667-549: The original wave had winds of 45 mph (72 km/h) before developing a closed low-level circulation. It has been suggested that some eastern Pacific Ocean tropical cyclones are formed out of tropical easterly waves that originate in North Africa as well. After developing into a tropical cyclone, some of those systems can then reach the Central Pacific Ocean, such as Hurricane Lane in 2018. During

8774-459: The panorama below, a wall of thunderstorms, only a half-hour's drive away, is a common sight from the sunny skies along the coast during the monsoon. Rainfall during the monsoon is not continuous. It varies considerably, depending on a variety of factors. There are usually distinct "burst" periods of heavy rain during the monsoon, and "break" periods with little or no rain. The variability is difficult to understand and predict, because it results from

8881-402: The passage of tropical waves and the entrainment of the remnants of tropical cyclones . Monsoon precipitation accounts for a substantial portion of annual precipitation in northwest Mexico and the Southwestern United States. Most of these areas receive over half their annual precipitation from the monsoon. Many desert plants are adapted to take advantage of this brief wet season. Because of

8988-477: The revolt was unsuccessful. In fact, it had the exact opposite effect, for the result of the rebellion was the establishment of the presidio at Tubac , the first permanent European settlement in Arizona. In 1768, the Spanish created the Provincia de las Californias , which included California and the Southwest US. Over approximately the next 50 years, the Spanish continued to explore the Southwest, and in 1776

9095-403: The ridge sets up in a few key locations, widespread and potentially severe thunderstorms can develop. Monsoon variability from one summer to the next is substantial, and exceeds the normal monsoon seasonal precipitation at most locations. For example, the normal monsoon precipitation at Tucson, Arizona is 6.06 inches (154 mm). The driest monsoon season measured 1.59 inches (40 mm), and

9202-680: The showers gradually diminish. An exception to the association of convection can occur in the Atlantic. Sometimes, a surge of dry air called the Saharan Air Layer (SAL) follows a tropical wave, leaving cloudless skies, as convection is capped by the dry layer inversion. Additionally, any dust in the SAL reflects sunlight, cooling the air below it. Tropical waves in the Atlantic basin develop from low-pressure disturbances, which develop as far east as Sudan in east Africa , and drift across

9309-402: The sought-after Southwestern architectural styles in the region inspired by blending Pueblo and Territorial styles, with Mediterranean Revival , Spanish Colonial architecture , Mission Revival architecture , Pueblo Deco , and Ranch-style houses in the form of the amalgamated Pueblo Revival and Territorial Revival architectures. This is due to the region's caballero heritage of

9416-468: The south the 37th parallel . In 1862 Nevada's eastern border shifted to the 38th meridian west from Washington , and finally to its current position at the 37th meridian west from Washington in 1866. The boundary modification in 1866 also included adding the southern triangular tip of the present-day state, taken from the Arizona Territory. From July 24–27, 1861 a Confederate force under

9523-402: The southeastern portion of the Southwest. Their settlements would evolve over time from pit-dwellings through pueblos and finally also incorporating cliff-dwellings. The Hohokam were the last of these ancestral cultures to develop, somewhere around AD 1, but they would grow to be the most populous of the three by AD 1300, despite being the smallest of the three in terms of area, covering most of

9630-492: The southernmost sections of Oregon, Idaho, and Wyoming, as well as parts of southwest Nebraska, western Kansas, Oklahoma, and Texas. By 1977, the Society's definition had narrowed to only the four states of Utah, Arizona, Colorado, and New Mexico; and by 1982 the portion of the Southwest in the United States, as defined by the Society, had shrunk to Arizona and New Mexico, with the southernmost strip of Utah and Colorado, as well as

9737-467: The southwest U.S. warm under intense solar heating. The prevailing winds start to flow from somewhat cooler moist ocean areas into hotter, dry land areas. Precipitation increases in late May to early June in southern Mexico and spreads along the western slopes of the Sierra Madre Occidental, reaching New Mexico and southeast Arizona in early July. It extends into the southwest United States as it matures in mid-July, when an area of high pressure , called

9844-509: The southwest portion. Beginning in approximately AD 600, the Hohokam began to develop an extensive series of irrigation canals; of the three major cultures in the Southwest, only the Ancestral Puebloans of the Chaco culture and the Hohokam developed irrigation as a means of watering their agriculture. Not long after the Hohokam reached the height of their culture, all three major cultures in

9951-421: The subtropical ridge also governs how far north the tropical easterly winds aloft can spread. If the ridge is too close to a particular area, the sinking air at its center suppresses thunderstorms and can result in a significant monsoon "break." If the ridge is too far away or too weak, the east winds around the high are inadequate to bring tropical moisture into the mountains of Mexico and southwest U.S. However, if

10058-419: The summer months, tropical waves can extend northward as far as the desert of the southwestern United States, producing spells of intensified shower activity embedded within the prevailing monsoon regime. A screaming eagle is a tropical wave with a convective pattern that loosely resembles the head of an eagle. This phenomenon is caused by shearing from either westerly winds aloft or strong easterly winds at

10165-408: The surface. These systems are typically located within 25 degrees latitude of the equator. Rain showers and surface winds gusting to 29 mph (47 km/h) are associated with these waves. They move across the ocean at a rate of 15 mph (24 km/h). Strong thunderstorm activity can be associated with the features when located east of a tropical upper tropospheric trough . The term

10272-481: The surrounding desert below. The sky islands also supply the surrounding desert foothills with flowing water during the spring runoff and after the summer storms of the New Mexican monsoon season . The Chihuahuan is a "rain shadow" desert, formed between two mountain ranges (the Sierra Madre Occidental on the west and the Sierra Madre Oriental on the east) which block oceanic precipitation from reaching

10379-533: The very southern tip of Nevada; while the Utah Territory consisted of Utah, most of Nevada, and portions of Wyoming and Colorado. The New Mexico Territory was expanded along its southern extent, to its current border, with the signing of the Gadsden Purchase Treaty on December 30, 1853, which was ratified by the U.S. Congress, with some slight alterations, in April 1854. The Colorado Territory

10486-474: The very southernmost part of Utah, southwestern Colorado, the very tip of west Texas, and triangle formed by the southern tip of Nevada. This will be the defined scope that is used in this article unless otherwise specified in a particular area. Parts of the other states make up the various areas that can be included in the Southwest, depending on the source. The Learning Center of the American Southwest (LCAS) does not rely on current state boundaries, and defines

10593-448: The way for a tourism boom, a trend led by restaurant and hotel entrepreneur Fred Harvey . The last two territories within the Southwest to achieve statehood were New Mexico and Arizona. By 1863, with the splitting off of the Arizona Territory, New Mexico reached its modern borders. They became states within forty days of one another. On January 6, 1912, New Mexico became the 47th state in the Union. Arizona would shortly follow, becoming

10700-575: The west to Las Vegas, New Mexico in the East. Reed's definition is roughly equivalent to the western half of the Learning Center of the American Southwest's definition, leaving out any portion of Kansas and Oklahoma, and much of Texas, as well as the eastern half of New Mexico. Since this article is about the Southwestern United States, the areas of Sonora and Chihuahua in Mexico will be excluded. The portion left includes Arizona and western New Mexico,

10807-543: The west were added after the Mexican–American War , the geographical "Southwest" expanded, and the relationship of these new acquisitions to the South itself became "increasingly unclear." However, archeologist, Erik Reed, gives a description which is the most widely accepted as defining the American Southwest, which runs from Durango, Colorado in the north, to Durango, Mexico, in the south, and from Las Vegas, Nevada in

10914-510: The westernmost metropolitan areas in the Southwest, while Albuquerque - Santa Fe and El Paso - Las Cruces dominate the easternmost metropolitan areas. Human history in the Southwest begins with the arrival of the Clovis culture , a Paleo-Indian hunter-gatherer culture which arrived sometime around 9000 BC. This culture remained in the area for several millennia. At some point they were replaced by three great Pre-Columbian Indian cultures:

11021-435: The wettest measured 13.84 inches (352 mm). Research since 2010 has investigated the possible causes behind North American monsoon variability. The following factors affect the North American monsoon: None of these factors can perfectly predict the variability. These factors are related to each other and are not independent. For example, sea surface temperatures affect all the other factors to some extent. In some years,

11128-423: Was admitted to the Union on October 31, 1864, becoming the 36th state. This was followed by the admittance to the Union of Colorado, which became the 38th state on August 1, 1876. Confederate Arizona was short-lived, however. By May 1862, Confederate forces had been driven out of the region by union troops. That same month a bill was introduced into the U.S. Congress, and on February 24, 1863 Abraham Lincoln signed

11235-463: Was almost non-existent outside of Nuevo México's Pueblos and Spanish or Mexican municipalities . Much of the area had been a part of New Spain and Mexico until the United States acquired the area through the Treaty of Guadalupe Hidalgo in 1848 and the smaller Gadsden Purchase in 1854. While the region's boundaries are not officially defined, there have been attempts to do so. One such definition

11342-485: Was organized on February 28, 1861, created out of lands then currently in the Utah, Kansas, Nebraska, and New Mexico territories. The Nevada Territory was also organized in 1861, on March 2, with land taken from the existing Utah Territory. Initially, only the western 2/3 of what is currently the State of Nevada was included in the territory, with its boundary to the east being the 39th meridian west from Washington , and to

11449-565: Was visited by its first non-Spanish Europeans, English trappers. In 1836, the Republic of Texas , which contained the easternmost of the Southwest United States, won its independence from Mexico. In 1845 the Republic of Texas was annexed by the United States and immediately became a state, bypassing the usual territory phase. The new state still contained portions of what would eventually become parts of other states. In 1846,

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