Colorado is a state of the Western United States encompassing most of the southern Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. It is the 8th most extensive and 21st most populous U. S. state. The estimated population of Colorado was 5,695,564 on July 1, 2018, an increase of 13.25% since the 2010 United States Census. The state was named for the Colorado River, which early Spanish explorers named the Río Colorado for the ruddy silt the river carried from the mountains; the Territory of Colorado was organized on February 28, 1861, on August 1, 1876, U. S. President Ulysses S. Grant signed Proclamation 230 admitting Colorado to the Union as the 38th state. Colorado is nicknamed the "Centennial State" because it became a state one century after the signing of the United States Declaration of Independence. Colorado is bordered by Wyoming to the north, Nebraska to the northeast, Kansas to the east, Oklahoma to the southeast, New Mexico to the south, Utah to the west, touches Arizona to the southwest at the Four Corners.
Colorado is noted for its vivid landscape of mountains, high plains, canyons, plateaus and desert lands. Colorado is part of the western and southwestern United States, is one of the Mountain States. Denver is most populous city of Colorado. Residents of the state are known as Coloradans, although the antiquated term "Coloradoan" is used. Colorado is notable for its diverse geography, which includes alpine mountains, high plains, deserts with huge sand dunes, deep canyons. In 1861, the United States Congress defined the boundaries of the new Territory of Colorado by lines of latitude and longitude, stretching from 37°N to 41°N latitude, from 102°02'48"W to 109°02'48"W longitude. After 158 years of government surveys, the borders of Colorado are now defined by 697 boundary markers and 697 straight boundary lines. Colorado and Utah are the only states that have their borders defined by straight boundary lines with no natural features; the southwest corner of Colorado is the Four Corners Monument at 36°59'56"N, 109°2'43"W.
This is the only place in the United States where four states meet: Colorado, New Mexico and Utah. The summit of Mount Elbert at 14,440 feet elevation in Lake County is the highest point in Colorado and the Rocky Mountains of North America. Colorado is the only U. S. state that lies above 1,000 meters elevation. The point where the Arikaree River flows out of Yuma County and into Cheyenne County, Kansas, is the lowest point in Colorado at 3,317 feet elevation; this point, which holds the distinction of being the highest low elevation point of any state, is higher than the high elevation points of 18 states and the District of Columbia. A little less than half of Colorado is flat and rolling land. East of the Rocky Mountains are the Colorado Eastern Plains of the High Plains, the section of the Great Plains within Nebraska at elevations ranging from 3,350 to 7,500 feet; the Colorado plains are prairies but include deciduous forests and canyons. Precipitation averages 15 to 25 inches annually. Eastern Colorado is presently farmland and rangeland, along with small farming villages and towns.
Corn, hay and oats are all typical crops. Most villages and towns in this region boast both a grain elevator. Irrigation water is available from subterranean sources. Surface water sources include the South Platte, the Arkansas River, a few other streams. Subterranean water is accessed through artesian wells. Heavy use of wells for irrigation caused underground water reserves to decline. Eastern Colorado hosts considerable livestock, such as hog farms. 70% of Colorado's population resides along the eastern edge of the Rocky Mountains in the Front Range Urban Corridor between Cheyenne and Pueblo, Colorado. This region is protected from prevailing storms that blow in from the Pacific Ocean region by the high Rockies in the middle of Colorado; the "Front Range" includes Denver, Fort Collins, Castle Rock, Colorado Springs, Pueblo and other townships and municipalities in between. On the other side of the Rockies, the significant population centers in Western Colorado are the cities of Grand Junction and Montrose.
The Continental Divide of the Americas extends along the crest of the Rocky Mountains. The area of Colorado to the west of the Continental Divide is called the Western Slope of Colorado. West of the Continental Divide, water flows to the southwest via the Colorado River and the Green River into the Gulf of California. Within the interior of the Rocky Mountains are several large parks which are high broad basins. In the north, on the east side of the Continental Divide is the North Park of Colorado; the North Park is drained by the North Platte River, which flows north into Nebraska. Just to the south of North Park, but on the western side of the Continental Divide, is the Middle Park of Colorado, drained by the Colorado River; the South Park of Colorado is the region of the headwaters of the South Platte River. In southmost Colorado is the large San Luis Valley, where the headwaters of the Rio Grande are located; the valley sits between the Sangre De Cristo Mountains and San Juan Mountains, consists of large desert lands that run into the mountains.
The Rio Grande drains due south into New Mexico and Texas. Across the Sangre de Cristo Range to the east of the S
Course of the Colorado River
The Colorado River is a major river of the western United States and northwest Mexico in North America. Its headwaters are in the Rocky Mountains. Located in north central Colorado it flows southwest through the Colorado Plateau country of western Colorado, southeastern Utah and northwestern Arizona where it flows through the Grand Canyon, it turns south near Las Vegas, forming the Arizona–Nevada border in Lake Mead and the Arizona–California border a few miles below Davis Dam between Laughlin and Needles, California California before entering Mexico in the Colorado Desert. Most of its waters are diverted into the Imperial Valley of Southern California. In Mexico its course forms the boundary between Sonora and Baja California before entering the Gulf of California; this article describes most of the major features along the river. The Colorado River rises on the Continental Divide at La Poudre Pass, in Rocky Mountain National Park, about 40 km north of Lake Granby, as a tiny stream draining a wet meadow.
At the river's headwater, the Continental Divide forms the boundary between the Gulf of Mexico and Pacific Ocean watersheds of North America, between Colorado's Grand and Larimer counties, the northern boundary of Rocky Mountain National Park. The river's first diversion is here at its headwater; the Grand Ditch redirects water from the Never Summer Mountains, which would have flowed into the Colorado River, to instead flow across the divide through La Poudre Pass to irrigate farmland to the east. About a mile downstream from its source, the Colorado River has carved its first canyon, the narrow, deep Little Yellowstone Canyon, it flows through the broad Kawuneeche Valley, where it is joined by U. S. Highway 34, which will parallel it to the town of Granby, it exits Rocky Mountain National Park, flowing into Shadow Mountain Lake and into Lake Granby, which are portions of the Colorado-Big Thompson Project, a large trans-basin water storage and delivery project that diverts water from the Colorado River under the Front Range mountains to provide an agricultural and municipal water supply for the northern Front Range and plains of Colorado.
Starting in Granby, the river is paralleled by U. S. Highway 40 to the town of Kremmling, by the tracks of the Union Pacific Railroad until about the Utah border, carrying the Amtrak California Zephyr passenger train; the canyons and valleys of the Upper Colorado River are among the scenic attractions for passengers on this rail route. Just downstream from Granby, the Colorado is joined by the Fraser River and flows through Windy Gap Reservoir, where more water is diverted to the Front Range via the Windy Gap Project. At Hot Sulphur Springs the river flows through Byers Canyon and is joined by the Williams Fork from the left and Muddy Creek from the right shortly thereafter. Just below Kremmling it is joined by the Blue River from the left before flowing through Gore Canyon, famous for its challenging rapids for the sport of whitewater rafting, where it drops until State Highway 131 crosses at the village of State Bridge, where the Piney River joins from the left; the Eagle River joins from the left in the town of Dotsero, from where Interstate 70 will parallel the Colorado until it enters Utah.
Below Dotsero the Colorado flows through Glenwood Canyon, emerging at the city of Glenwood Springs where the swift flowing Roaring Fork River, its second largest tributary in Colorado joins from the left. West of Glenwood Springs, the Colorado runs through a wider valley along the northern foothills of the Grand Mesa, passing the towns of New Castle, Rifle and De Beque, it flows through De Beque Canyon, where it is joined by Plateau Creek. The Colorado enters the Grand Valley, where its waters are used to irrigate over 40,000 acres of agricultural land. Here it passes Grand Junction, the largest town on the upper Colorado, where it is joined by the Gunnison River, its largest tributary within Colorado and second largest overall; the Gunnison drains from the northern San Juan Mountains, Elk Mountains and Sawatch Range – which includes Colorado's highest peak, 14,440-foot Mount Elbert – and carves the Black Canyon of the Gunnison before joining the Colorado. In the Grand Valley the Colorado becomes a meandering river in contrast to the steep mountain canyons above Grand Junction.
It ranges from 6 to 30 ft in depth with occasional deeper areas. From there the Colorado turns northwest, past Fruita and entering Ruby Canyon as it approaches the Colorado Plateau, it turns southwest once again just before entering Utah. In Utah the Colorado enters the high desert canyon country of the Colorado Plateau, flowing swiftly southwest through Westwater Canyon. Near Dewey it picks up the Dolores River, which together with its tributary the San Miguel drains the western slope of the San Juan Mountains, it passes the Fisher Towers and forms part of the southern border of Arches National Park before entering the Moab Valley at Moab. Just below Moab it carves through a 1,000-foot deep mountain pass known as "The Portal"; the Colorado passes by Dead Horse Point State Park before entering the backcountry of Canyonlands National Park where it is joined from the north by the Green River, its biggest tributary. The Green, flowing from the Wind River Range of western Wyoming, drains 48,000 square miles in southwest Wyoming, northeast Utah and northwest Colorado.
It is much longer than the Colorado above their confluence and carries a larger load of silt, though the Colorado has a greater flow. Before an act of Congress changed the name in 1921 this confluence marked the official beginning of the Colorado River prop
Berthoud Pass is a high mountain pass in the Rocky Mountains of central Colorado in the United States. The pass is located west of Denver, provides a high route between upper Clear Creek Canyon to the upper valley of the Fraser River in Middle Park to the north; the pass traverses the continental divide at the Front Range, on the border between Clear Creek County and Grand County. The pass is named for Edward L. Berthoud, the chief surveyor of the Colorado Central Railroad during the 1870s. Accompanied by Jim Bridger, Berthoud discovered the pass in July 1861 while surveying a possible route for the railroad. Berthoud concluded that the pass was suitable as a wagon road, but not as a railroad, was hired by the Central Overland California and Pikes Peak Express Company to survey a route over the pass to Salt Lake; the pass is the route of U. S. Highway 40, north of its junction with Interstate 70 in Clear Creek Canyon, it provides the fastest road access to Winter Park and a secondary route to Steamboat Springs from Denver and the Colorado Front Range.
However, the pass is one of the most notoriously difficult passes in Colorado for motorists, based on its height as well as the steep grades on both sides and the large number of switchbacks on the southern side of the pass. At least 55 avalanche paths have been mapped on Berthoud Pass. S. Highway 40, a smaller subset of paths intersecting the roadway at multiple points on the pass. In 2015, CDOT installed an automated propane-fueled avalanche mitigation system consisting of five units that create concussive blasts to mitigate snow slab buildup on avalanche path #5, Stanley. In 1902, the 3.5 mile Berthoud Pass Ditch began diverting water from the headwaters of the Fraser River over the continental divide into the basin of Clear Creek. This water was used for irrigation, but the cities of Northglenn and Golden purchased the ditch in the mid-1980s; the ditch has a capacity of 53.4 cubic feet per second, The ditch was blocked in 1999 by the collapse of the tunnel under the parking lot at the summit of the pass, but it was repaired the next year.
In the decade since the repairs, the ditch has diverted on the order of 500 acre-feet per year. Once home to the now-defunct Berthoud Pass Ski Area, the pass is a destination for local backcountry skiers and snowshoers due to its abundance of steep and challenging terrain and plentiful snow averaging 500 inches annually; the twisting road on both sides of the pass makes "car shuttles" possible, eliminating the need for skiers and snowboarders to hike back to the top of the pass after each run. The ski resort was closed in 2002 due to financial problems caused by lack of water and sewage at the top of the pass. In 2003 the lifts were taken down, while some people continued to ski using snowcats for lift transportation. In 2005 the Colorado DOT began using a fund to restore the area to its natural state. First on the list was the demolition of the historic lodge. A new warming hut was opened at the top of the pass in May 2008, along with an expanded parking area, two scenic viewing areas and a new summit marker sign.
The ski lodge and facilities had been in use since the early 1950s and the new warming hut includes modern features such as composting toilets, radiant floor heating and green construction. Berthoud Ski resort is claimed by some to lift in Colorado; some say it was the first resort to welcome snowboarders. The summit of Berthoud Pass is located at 39°47′53.70″N 105°46′36.88″W. Founded in 2003, Friends of Berthoud Pass is a grassroots collective of backcountry enthusiasts committed to preserving the legacy of public recreation at Berthoud Pass, they are a non-profit 501c tax exempt organization managed by a volunteer executive board and supported by a diverse and active member base. Berthoud Pass is a unique environment, where a major highway crosses the Continental Divide in a topographically and climatically ideal location that lends itself to a lengthy season of challenging deep powder skiing; this combination of elements at Berthoud Pass creates a unique set of circumstances for land managers, FOBP has played a pivotal role in giving public voice to the policy process.
In its short history Friends of Berthoud Pass has endeavored to fashion a new paradigm in winter recreation on public land. They have mobilized public involvement in lobbying the US Forest Service to incorporate the needs and wishes of winter backcountry users in redevelopment plans and positioned themselves as a key stakeholder in the public policy process; the Friends of Berthoud Pass avalanche education curriculum has expanded from two classroom sessions in 2004 that reached 100 people, to a 2008 roster of eight classroom lectures educating more than 1,000 individuals in basic avalanche awareness and more than 150 participants in an on-snow practical course. 9. Jack Kerouac. Berthoud Pass, Colorado USGS TopoZone listing Friends of Berthoud Pass Berthoud Pass Ski Area's History
The Mojave Desert is an arid rain-shadow desert and the driest desert in North America. It is in the southwestern United States within southeastern California and southern Nevada, it occupies 47,877 sq mi. Small areas extend into Utah and Arizona, its boundaries are noted by the presence of Joshua trees, which are native only to the Mojave Desert and are considered an indicator species, it is believed to support an additional 1,750 to 2,000 species of plants. The central part of the desert is sparsely populated, while its peripheries support large communities such as Las Vegas, Lancaster, Victorville, St. George; the Mojave Desert is bordered by the Great Basin Desert to its north and the Sonoran Desert to its south and east. Topographical boundaries include the Tehachapi Mountains to the west, the San Gabriel Mountains and San Bernardino Mountains to the south; the mountain boundaries are distinct because they are outlined by the two largest faults in California – the San Andreas and Garlock faults.
The Mojave Desert displays typical range topography. Higher elevations above 2,000 ft in the Mojave are referred to as the High Desert; the Mojave Desert occupies less than 50,000 sq mi, making it the smallest of the North American deserts. The Mojave Desert is referred to as the "high desert", in contrast to the "low desert", the Sonoran Desert to the south; the Mojave Desert, however, is lower than the Great Basin Desert to the north. The spelling Mojave originates from the Spanish language while the spelling Mohave comes from modern English. Both are used today, although the Mojave Tribal Nation uses the spelling Mojave; the Mojave Desert receives less than 2 inches of rain a year and is between 2,000 and 5,000 feet in elevation. The Mojave Desert contains the Mojave National Preserve, as well as the lowest and hottest place in North America: Death Valley at 282 ft below sea level, where the temperature surpasses 120 °F from late June to early August. Zion National Park in Utah lies at the junction of the Mojave, the Great Basin Desert, the Colorado Plateau.
Despite its aridity, the Mojave has long been a center of alfalfa production, fed by irrigation coming from groundwater and from the California Aqueduct. The Mojave is a desert of two distinct seasons. Winter months bring comfortable daytime temperatures, which drop to around 25 °F on valley floors, below 0 °F at the highest elevations. Storms moving from the Pacific Northwest can bring rain and in some places snow. More the rain shadow created by the Sierra Nevada as well as mountain ranges within the desert such as the Spring Mountains, bring only clouds and wind. In longer periods between storm systems, winter temperatures in valleys can approach 80 °F. Spring weather continues to be influenced by Pacific storms, but rainfall is more widespread and occurs less after April. By early June, it is rare for another Pacific storm to have a significant impact on the region's weather. Summer weather is dominated by heat. Temperatures on valley floors can soar above 130 °F at the lowest elevations. Low humidity, high temperatures, low pressure, draw in moisture from the Gulf of Mexico creating thunderstorms across the desert southwest known as the North American monsoon.
While the Mojave does not get nearly the amount of rainfall the Sonoran desert to the south receives, monsoonal moisture will create thunderstorms as far west as California's Central Valley from mid-June through early September. Autumn is pleasant, with one to two Pacific storm systems creating regional rain events. October is one of the sunniest months in the Mojave. After temperature, wind is the most significant weather phenomenon in the Mojave. Across the region windy days are common. During the June Gloom, cooler air can be pushed into the desert from Southern California. In Santa Ana wind events, hot air from the desert blows into the Los Angeles basin and other coastal areas. Wind farms in these areas generate power from these winds; the other major weather factor in the region is elevation. The highest peak within the Mojave is Charleston Peak at 11,918 feet, while the Badwater Basin in Death Valley is 279 feet below sea level. Accordingly and precipitation ranges wildly in all seasons across the region.
The Mojave Desert has not supported a fire regime because of low fuel loads and connectivity. However, in the last few decades, invasive annual plants such as some within the genera Bromus and Brassica have facilitated fire; this has altered many areas of the desert. At higher elevations, fire regimes are infrequent; the Mojave Desert is defined by numerous mountain ranges creating its xeric conditions. These ranges create valleys, endorheic basins, salt pans, seasonal saline lakes when precipitation is high enough. These
Arizona is a state in the southwestern region of the United States. It is part of the Western and the Mountain states, it is the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona shares the Four Corners region with Utah and New Mexico. Arizona is the 48th state and last of the contiguous states to be admitted to the Union, achieving statehood on February 14, 1912, coinciding with Valentine's Day. Part of the territory of Alta California in New Spain, it became part of independent Mexico in 1821. After being defeated in the Mexican–American War, Mexico ceded much of this territory to the United States in 1848; the southernmost portion of the state was acquired in 1853 through the Gadsden Purchase. Southern Arizona is known for its desert climate, with hot summers and mild winters. Northern Arizona features forests of pine, Douglas fir, spruce trees. There are ski resorts in the areas of Flagstaff and Tucson. In addition to the Grand Canyon National Park, there are several national forests, national parks, national monuments.
About one-quarter of the state is made up of Indian reservations that serve as the home of 27 federally recognized Native American tribes, including the Navajo Nation, the largest in the state and the United States, with more than 300,000 citizens. Although federal law gave all Native Americans the right to vote in 1924, Arizona excluded those living on reservations in the state from voting until the state Supreme Court ruled in favor of Native American plaintiffs in Trujillo v. Garley; the state's name appears to originate from an earlier Spanish name, derived from the O'odham name alĭ ṣonak, meaning "small spring", which applied only to an area near the silver mining camp of Planchas de Plata, Sonora. To the European settlers, their pronunciation sounded like "Arissona"; the area is still known as alĭ ṣonak in the O'odham language. Another possible origin is the Basque phrase haritz ona, as there were numerous Basque sheepherders in the area. A native Mexican of Basque heritage established the ranchería of Arizona between 1734 and 1736 in the current Mexican state of Sonora, which became notable after a significant discovery of silver there, c.
1737. There is a misconception. For thousands of years before the modern era, Arizona was home to numerous Native American tribes. Hohokam and Ancestral Puebloan cultures were among the many that flourished throughout the state. Many of their pueblos, cliffside dwellings, rock paintings and other prehistoric treasures have survived, attracting thousands of tourists each year; the first European contact by native peoples was with Marcos de Niza, a Spanish Franciscan, in 1539. He explored parts of the present state and made contact with native inhabitants the Sobaipuri; the expedition of Spanish explorer Coronado entered the area in 1540–1542 during its search for Cíbola. Few Spanish settlers migrated to Arizona. One of the first settlers in Arizona was José Romo de Vivar. Father Kino was the next European in the region. A member of the Society of Jesus, he led the development of a chain of missions in the region, he converted many of the Indians to Christianity in the Pimería Alta in the 1690s and early 18th century.
Spain founded presidios at Tubac in 1752 and Tucson in 1775. When Mexico achieved its independence from the Kingdom of Spain and its Spanish Empire in 1821, what is now Arizona became part of its Territory of Nueva California known as Alta California. Descendants of ethnic Spanish and mestizo settlers from the colonial years still lived in the area at the time of the arrival of European-American migrants from the United States. During the Mexican–American War, the U. S. Army occupied the national capital of Mexico City and pursued its claim to much of northern Mexico, including what became Arizona Territory in 1863 and the State of Arizona in 1912; the Treaty of Guadalupe Hidalgo specified that, in addition to language and cultural rights of the existing inhabitants of former Mexican citizens being considered as inviolable, the sum of US$15 million dollars in compensation be paid to the Republic of Mexico. In 1853, the U. S. acquired the land south below the Gila River from Mexico in the Gadsden Purchase along the southern border area as encompassing the best future southern route for a transcontinental railway.
What is now known as the state of Arizona was administered by the United States government as part of the Territory of New Mexico until the southern part of that region seceded from the Union to form the Territory of Arizona. This newly established territory was formally organized by the Confederate States government on Saturday, January 18, 1862, when President Jefferson Davis approved and signed An Act to Organize the Territory of Arizona, marking the first official use of the name "Territory of Arizona"; the Southern territory supplied the Confederate government with men and equipment. Formed in 1862, Arizona scout companies served with the Confederate States Army duri
Sonora Estado Libre y Soberano de Sonora, is one of 31 states that, with Mexico City, comprise the 32 federal entities of United Mexican States. It is divided into 72 municipalities. Sonora is bordered by the states of Chihuahua to the east, Baja California to the northwest and Sinaloa to the south. To the north, it shares the U. S.–Mexico border with the states of Arizona and New Mexico, on the west has a significant share of the coastline of the Gulf of California. Sonora's natural geography is divided into three parts: the Sierra Madre Occidental in the east of the state, it is arid or semiarid deserts and grasslands, with only the highest elevations having sufficient rainfall to support other types of vegetation. Sonora is home to eight indigenous peoples, including the Mayo, the O’odham, the Yaqui, Seri, it has been economically important for its agriculture and mining since the colonial period, for its status as a border state since the Mexican–American War. With the Gadsden Purchase, Sonora lost more than a quarter of its territory.
From the 20th century to the present, industry and agribusiness have dominated the economy, attracting migration from other parts of Mexico. Several theories exist as to the origin of the name "Sonora". One theory states that the name was derived from Nuestra Señora, the name given to the territory when Diego de Guzmán crossed the Yaqui River on the day of Nuestra Señora del Rosario, which falls on 7 October with the pronunciation changing because none of the indigenous languages of the area have the ñ sound. Another theory states that Álvar Núñez Cabeza de Vaca and his companions, who had wrecked off the Florida coast and made their way across the continent, were forced to cross the arid state from north to south, carrying an image of Nuestra Señora de las Angustias on a cloth, they encountered the Opata, who could not pronounce Señora, instead saying Sonora. A third theory, written by Father Cristóbal de Cañas in 1730, states that the name comes from the word for a natural water well, which the Spaniards modified to "Sonora".
The first record of the name Sonora comes from explorer Francisco Vásquez de Coronado, who passed through the state in 1540 and called part of the area the Valle de la Sonora. Francisco de Ibarra traveled through the area in 1567 and referred to the Valles de Señora; the literal meaning of "sonora" in Spanish is "sonorous" or "loud." Evidence of human existence in the state dates back over 10,000 years, with some of the best-known remains at the San Dieguito Complex in the El Pinacate Desert. The first humans were nomadic hunter gatherers who used tools made from stones and wood. During much of the prehistoric period, the environmental conditions were less severe than they are today, with similar but more dense vegetation spread over a wider area; the oldest Clovis culture site in North America is believed to be El Fin del Mundo in northwestern Sonora. It was discovered during a 2007 survey, it features occupation dating around 13,390 calibrated years BP. In 2011, remains of Gomphothere were found.
Agriculture first appeared around 400 200 CE in the river valleys. Remains of ceramics have been found dating from 750 CE with diversification from 800 and 1300 CE Between 1100 and 1350, the region had complex small villages with well-developed trade networks; the lowland central coast, seems never to have adopted agriculture. Because Sonora and much of the northwest does not share many of the cultural traits of that area, it is not considered part of Mesoamerica. Though evidence exists of trade between the peoples of Sonora and Mesoamerica, Guasave in Sinaloa is the most north-westerly point considered Mesoamerican. Three archaeological cultures developed in the low, flat areas of the state near the coast: the Trincheras tradition, the Huatabampo tradition, the Central Coast tradition; the Trincheras tradition is dated to between 750 and 1450 CE and known from sites in the Altar and Concepción valleys, but its range extended from the Gulf of California into northern Sonora. The tradition is named after trenches found in a number of sites, the best known of, the Cerro de Trincheras.
The Huatabampo tradition is centered south of the Trincheras along the coast, with sites along extinct lagoons and river valleys. This tradition has a distinctive ceramic complex. Huatabampo culture shows similarities with the Chametla to the Hohokam to the north; this ended around 1000 CE. Unlike the other two traditions, the Central Coast remained a hunter-gatherer culture, as the area lacks the resources for agriculture; the higher elevations of the state were dominated by the Casas Grandes and Río Sonora tradition. The Río Sonora culture is located in central Sonora from the border area to modern Sinaloa. A beginning date for this culture has not been determined but it disappeared by the early 14th century; the Casas Grandes tradition in Sonora was an extension of the Río Sonora tradition based in the modern state of Chihuahua, which exterted its influence down to parts of the Sonoran coast. Climatic changes in the middle of the 15th century resulted in the increased desertification of northwest Mexico in general.
This is the probable cause for the drastic decrease in the number and size of settlements starting around this time. The peoples that remained in the area reverted to a less complex social organiz