Angeles National Forest
The Angeles National Forest of the U. S. Forest Service is located in the San Gabriel Mountains and Sierra Pelona Mountains within Los Angeles County in southern California; the ANF manages a majority of the San Gabriel Mountains National Monument. The national forest was established in 1908, incorporating the first San Bernardino National Forest and parts of the former Santa Barbara and San Gabriel National Forests. Angeles National Forest headquarters are located in California; the Angeles National Forest covers a total of 700,176 acres, protecting large areas of the San Gabriel Mountains and Sierra Pelona Mountains. It is located just north of the densely inhabited metropolitan area of Greater Los Angeles. While within Los Angeles County, a small part extends eastward into southwestern San Bernardino County, in the Mount San Antonio area, a tiny section extends westward into northeastern Ventura County, in the Lake Piru area; the San Gabriel Mountains National Monument, established in 2014 and managed by the U.
S. Forest Service, is within the Angeles National Forest; the John D. Dingell, Jr. Conservation and Recreation Act of 2019 established the Saint Francis Dam Disaster National Memorial and Saint Francis Dam Disaster National Monument at and around the ruins of the St. Francis Dam in the Forest's San Francisquito Canyon; the Angeles National Forest contains five nationally designated wilderness areas. Two of these extend into neighboring San Bernardino National Forest: Cucamonga Wilderness — in San Bernardino NF Magic Mountain Wilderness Pleasant View Ridge Wilderness San Gabriel Wilderness Sheep Mountain Wilderness — in San Bernardino NF The San Gabriel Forest Reserve was established on December 20, 1892, the San Bernardino Forest Reserve was established on February 25, 1893, the Santa Barbara Forest Reserve was established on December 22, 1903. Together, they became National Forests on March 4, 1907, they were combined on July 1, 1908, with all of the San Bernardino forest and portions of San Gabriel forest and Santa Barbara forest composing the new Angeles National Forest.
On September 30, 1925, portions of the Angeles National Forest and the Cleveland National Forest were detached to re-establish the San Bernardino National Forest. Angeles National Forest is registered as California Historical Landmark #717, for being the first National Forest in the state; the campgrounds at Broken Blade, Twisted Arrow and Pima Loops were closed on July 26, 2013 after squirrel infected with bubonic plague was discovered. Station FireIn the Station Fire, more than 161,000 acres of the forest were burned by an arson fire that began on August 26, 2009, near Angeles Crest Highway in La Cañada and spread, fueled by dry brush that had not burned for over 150 years; the fire burned for more than a month and was the worst in Los Angeles County history, charring one-fourth of the forest, displacing wildlife, destroying 91 homes and outbuildings and the family-owned Hidden Springs Cafe. During the fire, two firefighters died after driving off the Mt. Gleason County Road looking for an alternate route to get the inmates out at Camp 16.
The Station Fire threatened the Mount Wilson Observatory atop Mt. Wilson; the site includes two telescopes, two solar towers, transmitters for 22 television stations, several FM radio stations, police and fire department emergency channels. Although the fire scorched one side of the outhouse at amateur-owned Stony Ridge Observatory, six miles northeast of Mt. Wilson, aside from minor damage from smoke and ash infiltration, the remainder of the observatory and its historic 30-inch Carroll telescope survived. 2012 firesSeveral 2012 wildfires occurred, burning hundreds of acres across the forest-covered mountain range. The Angeles National Forest manages the habitats and fauna ecosystems, watersheds; some of the rivers with watersheds within its boundaries provide valuable non-groundwater recharge water for Southern California. The existing protected and restored native vegetation absorb and slow surface runoff of rainwater to minimize severe floods and landslides in adjacent communities; the land within the forest is diverse, both in terrain.
Elevations range from 1,200 to 10,064 ft. The Pacific Crest Trail crosses the forest. Much of this National Forest is covered with dense chaparral shrub forests with oak woodlands, which changes to pine and fir-covered slopes in the higher elevations. Subsequent to the fire there was a heavy growth of poodle-dog bush triggered by the fire's effect on dormant seeds, that lasted for several years; the plant produces prolific lavender flowers. As visitors to the Forest discovered, contact with it may cause a poison-oak-like rash. Tree species for which the forest is important include bigcone Douglas-fir, Coulter pine, California walnut; the National Forest contains some 29,000 acres of old growth, with: Jeffrey pine forests and mixed conifer forests, lodgepole pine the most abundant types. This forest is home to black bears, gray foxes, bobcats and coyotes. A National Forest Adventure Pass is required for parking at many locations in the Angeles National Forest and other National Forests in Southern California, this can be obtained online or from visitor centers and local merchants.
Los Angeles County has declared. There are many other areas that do not requi
Barack Hussein Obama II is an American attorney and politician who served as the 44th president of the United States from 2009 to 2017. A member of the Democratic Party, he was the first African American, he served as a U. S. senator from Illinois from 2005 to 2008. Obama was born in Hawaii. After graduating from Columbia University in 1983, he worked as a community organizer in Chicago. In 1988, he enrolled in Harvard Law School, where he was the first black president of the Harvard Law Review. After graduating, he became a civil rights attorney and an academic, teaching constitutional law at the University of Chicago Law School from 1992 to 2004, he represented the 13th district for three terms in the Illinois Senate from 1997 until 2004 when he ran for the U. S. Senate, he received national attention in 2004 with his March primary win, his well-received July Democratic National Convention keynote address, his landslide November election to the Senate. In 2008, he was nominated for president a year after his campaign began and after a close primary campaign against Hillary Clinton.
He was elected over Republican John McCain and was inaugurated on January 20, 2009. Nine months he was named the 2009 Nobel Peace Prize laureate. Regarded as a centrist New Democrat, Obama signed many landmark bills into law during his first two years in office; the main reforms that were passed include the Patient Protection and Affordable Care Act, the Dodd–Frank Wall Street Reform and Consumer Protection Act, the Don't Ask, Don't Tell Repeal Act of 2010. The American Recovery and Reinvestment Act of 2009 and Tax Relief, Unemployment Insurance Reauthorization, Job Creation Act of 2010 served as economic stimulus amidst the Great Recession. After a lengthy debate over the national debt limit, he signed the Budget Control and the American Taxpayer Relief Acts. In foreign policy, he increased U. S. troop levels in Afghanistan, reduced nuclear weapons with the United States–Russia New START treaty, ended military involvement in the Iraq War. He ordered military involvement in Libya in opposition to Muammar Gaddafi.
He ordered the military operations that resulted in the deaths of Osama bin Laden and suspected Yemeni Al-Qaeda operative Anwar al-Awlaki. After winning re-election by defeating Republican opponent Mitt Romney, Obama was sworn in for a second term in 2013. During this term, he promoted inclusiveness for LGBT Americans, his administration filed briefs that urged the Supreme Court to strike down same-sex marriage bans as unconstitutional. He advocated for gun control in response to the Sandy Hook Elementary School shooting, indicating support for a ban on assault weapons, issued wide-ranging executive actions concerning climate change and immigration. In foreign policy, he ordered military intervention in Iraq in response to gains made by ISIL after the 2011 withdrawal from Iraq, continued the process of ending U. S. combat operations in Afghanistan in 2016, promoted discussions that led to the 2015 Paris Agreement on global climate change, initiated sanctions against Russia following the invasion in Ukraine and again after Russian interference in the 2016 United States elections, brokered a nuclear deal with Iran, normalized U.
S. relations with Cuba. During his term in office, America's reputation in global polling improved. Evaluations of his presidency among historians, political scientists, the general public place him among the upper tier of American presidents. Obama left office and retired in January 2017 and resides in Washington, D. C. A December 2018 Gallup poll found Obama to be the most admired man in America for an unprecedented 11th consecutive year, although Dwight D. Eisenhower was selected most admired in twelve non-consecutive years. Obama was born on August 4, 1961, at Kapiolani Medical Center for Women and Children in Honolulu, Hawaii, he is the only president, born outside of the contiguous 48 states. He was born to a black father, his mother, Ann Dunham, was born in Kansas. His father, Barack Obama Sr. was a Luo Kenyan from Nyang'oma Kogelo. Obama's parents met in 1960 in a Russian language class at the University of Hawaii at Manoa, where his father was a foreign student on a scholarship; the couple married in Hawaii, on February 2, 1961, six months before Obama was born.
In late August 1961, Barack and his mother moved to the University of Washington in Seattle, where they lived for a year. During that time, the elder Obama completed his undergraduate degree in economics in Hawaii, graduating in June 1962, he left to attend graduate school on a scholarship at Harvard University, where he earned an M. A. in economics. Obama's parents divorced in March 1964. Obama Sr. returned to Kenya in 1964, where he married for a third time and worked for the Kenyan government as the Senior Economic Analyst in the Ministry of Finance. He visited his son in Hawaii only once, at Christmas time in 1971, before he was killed in an automobile accident in 1982, when Obama was 21 years old. Recalling his early childhood, Obama said, "That my father looked nothing like the people around me – that he was black as pitch, my mother white as milk – registered in my mind." He described his struggles as a young adult to reconcile social perceptions of his multira
Newhall Pass is a low mountain pass in Los Angeles County, California. Called Fremont Pass and San Fernando Pass, with Beale's Cut, it separates the Santa Susana Mountains from the San Gabriel Mountains. Although the pass was discovered in August 1769 by Catalan explorer Gaspar de Portolà, it was named for Henry Newhall, a significant businessman in the area during the 19th century. Newhall Pass links the San Fernando Valley to the Santa Clarita Valley and is a main entry to the Greater Los Angeles area; the pass is known for the historic San Fernando Tunnel. In the pass weather can vary from triple-digit heat in the summer to below zero in winter. Snow is possible in December to February, but is rare, when it does occur can lead to heavy traffic and accidents; the pass can have heavy flooding in La Niña and El Niño events. Wildfires nearby have occasionally closed down the pass and California State Route 14. Newhall Pass was named'Fremont Pass' for General John C. Frémont, thought to have passed through it in 1847 on his way to sign the Treaty of Cahuenga, but he went east of the pass on the El Camino Viejo.
In 1853, a Los Angeles businessman, Henry Clay Wiley installed a windlass atop the Fremont Pass to speed and ease the ascent and descent of the steep Santa Clara Divide. He built a tavern and stable nearby. In 1854, Wiley sold out to Sanford and Cyrus Lyon and it began to be called Lyons Station. At the same time, Phineas Banning obtained the business of supplying Fort Tejon; the steep pass was made easier to cross with a deep slot-like road cut by Charles H. Brindley, Andrés Pico, James R. Vineyard, to whom the State of California awarded a twenty-year contract to maintain the turnpike and collect tolls. Thus, the "San Fernando Mountain," the most daunting obstacle along the Fort Tejon Road, the main inland route from Los Angeles to the north, was cut through. Butterfield Overland Mail, a stagecoach that operated mail between St. Louis and San Francisco began using it directly. In 1861, a landowner and surveyor named Edward Beale was appointed by President Abraham Lincoln as the federal Surveyor General of California and Nevada.
Beale challenged General Pico's loyalty to the new president and in 1863, Beale was awarded the right to collect the toll in the pass. Beale maintained rights to the cut for the next twenty years and so it became known as "Beale's Cut."Beale's Cut was deepened to 90 feet. It lasted as a transportation passage in the neighborhood of present-day Newhall Pass until construction of the Newhall Tunnel was completed in 1910. Beale's Cut appeared in many silent western movies; the location became a favorite of movie producers like D. W. Griffith. In Ford's 1923 film Three Jumps Ahead, American film actor Tom Mix is filmed jumping over the pass. John Ford used the location in at least four films over a twenty-year period beginning as early as 1917. Still in existence today, it is no longer passable by automobiles, it suffered a partial collapse during the Northridge Earthquake, on January 17, 1994, now is about 30 feet deep. It is visible from the Sierra Highway about one mile north from the intersection of The Old Road and Sierra Highway, just after the first bridge under SR 14.
It lies between Sierra Highway and the new freeway, about a quarter mile to the northeast of a stone marker. Beale's Cut is difficult to find today because it is fenced off and not close enough to the Sierra Highway to be seen. Newhall Pass is named after businessman Henry Newhall, whose land holdings formed the basis of the city of Santa Clarita. Newhall came to California from Saugus, Massachusetts during the California Gold Rush in 1850. Over time he purchased a number of properties in the state, the most significant being the 46,460-acre Rancho San Francisco in northern Los Angeles County. Within this territory, he granted a right-of-way to Southern Pacific through what is now Newhall Pass, he sold them a portion of the land, upon which the company built a town they named after him: Newhall; the first station built on the line he named for Saugus. After his death in 1882 his family incorporated the Newhall Farming Company. Newhall Pass remains a main traffic route, as the Newhall Pass interchange of Interstate 5 and State Route 14, as well as Sierra Highway, Foothill Boulevard, San Fernando Road travel through the pass.
The Sierra Highway crossing was once the Newhall Tunnel, built by Los Angeles County in 1910 to replace Beale's Cut. Metrolink's Antelope Valley Line and the Union Pacific Railroad go through the pass via the San Fernando Tunnel; the 6,940-foot-long railroad tunnel took a half to complete. Over 1,500 Chinese laborers took part in the tunnel construction, which began at the south end of the mountain on March 22, 1875. Many of them had prior experience working on Southern Pacific's tunnels in the Tehachapi Pass. Due to the sandstone composition of the mountain, saturated with water and oil, frequent cave-ins occurred and the bore had to be shored up by timbers during excavation; the initial location for the north end of the tunnel was near Lyons Station Stagecoach Stop, abandoned due to frequent cave-ins caused by oil-soaked rock. The north end was moved a little further west towards the present town of California; the north end of the tunnel excavation commenced in June 1875. Water was a constant problem during construction and pumps were utilized to keep the tunnel from flooding.
Workers digging from both the north and south ends of the tun
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
Antenna farm or satellite dish farm or just dish farm are terms used to describe an area dedicated to television or radio telecommunications transmitting or receiving antenna equipment, such as C, Ku or Ka band satellite dish antennas, UHF/VHF/AM/FM transmitter towers or mobile cell towers. The history of the term "antenna farm" is uncertain. In telecom circles, any area with more than three antennas could be referred to as an antenna farm. In the case of an AM broadcasting station, the multiple mast radiators may all be part of an antenna system for a single station, while for VHF and UHF the site may be under joint management. Alternatively, a single tower with many separate antennas is called a "candelabra tower". Commercial antenna farms are managed by radio stations, television stations, satellite teleports or military organizations and are very secure facilities with access limited to broadcast engineers, RF engineers or maintenance technicians; this is not only for the physical security of the location, but for safety, as there may be a radiation hazard unless stations are powered-down.
Where terrain and road access allows, mountaintop sites are attractive for non-AM broadcast stations and others, because it increases the stations' height above average terrain, allowing them to reach further by avoiding obstructions on the ground, by increasing the radio horizon. With a clearer line of sight in both cases, more signal can be received. While the same is true of a tall tower, like Paris’ Eiffel tower, such towers are expensive and difficult to access the top of, may collect and drop large amounts of ice in winter, or collapse in a severe ice storm and/or high winds. Multiple small towers allow stations to have backup facilities co-located on each other's towers for redundancy. Satellite antenna farms are located at remote locations, far away from urban development high rise buildings or airplane flight paths, to avoid and minimize disruption to transmission and reception, so as to not be an eyesore. Although most radio and TV stations are in fierce competition with each other in their broadcast markets, they will locate their broadcasting antennas near each other, in some cases, will share land or towers with each other, in the interests of space, land availability, the cost of putting a transmission building on top of a mountain.
Most metropolitan areas have at least one antenna farm, such as Mount Wilson in greater Los Angeles, Sweat Mountain in metro Atlanta, Farnsworth Peak for the Salt Lake Valley, Riverview in Tampa, Baltimore's Television Hill and Slide Mountain in the Reno/Tahoe area. Some cities instead have combined many stations onto one tower through diplexers into just one or two antennas, such as atop the Empire State Building in New York, the landmark Sutro Tower of San Francisco, or the huge Miami Gardens tower serving the Miami and Fort Lauderdale region. Cleveland, Ohio has its antenna farm in the suburb of Ohio due to Parma's high elevation. In central Oklahoma City most of the city's media outlets transmitter and tower facilities are located between the Kilpatrick Turnpike to the south and Interstate 44 to the north, Broadway Extension to the west and Interstate 35 to the east with Britton Road being the central thoroughfare. In addition, all three network affiliates and one of the 3 major radio groups have their studio facilities located within the Oklahoma City tower farm.
In the Appalachian Mountains of the Eastern United States, Poor Mountain serves most of the FM and TV stations in the Roanoke/Lynchburg market. Holston Mountain in upper East Tennessee is home to most of the FM and TV stations in the Tri-Cities DMA. Other examples are Signal Mountain near Chattanooga, Sharp's Ridge in Knoxville and Paris Mountain in Greenville, South Carolina. Other examples of co-located towers on mountain peaks in the United States are on Red Mountain in Birmingham, Alabama; the most famous broadcast antenna farm of all is the World Trade Center Tower One, on which many of the New York City television and several FM stations had their antennas. All were lost when Twin Towers One and Two collapsed after the September 11 attacks in 2001. Most of those stations reverted to broadcasting from their previous home, 200 feet lower, on the Empire State Building. Antenna farms have been the source of complaints from local neighborhoods when a new tower is added; this has been so for TV stations, which have been pursuing with alacrity the construction of new digital television antennas.
Because many of these towers are full, or were built well before there was the expectation of DTV, many stations have been forced to go through the greater expense of constructing a new tower. One such situation was in the late 1990s and early to mid-2000s. Many of the Denver metropolitan area TV stations transmitted analog TV from Lookout Mountain, but needed the extra space for more antennas. Additionally, since many people live on Lookout Mountain, there was the concern about safety, not only from falling ice or the slight risk of a tower collapse, but ongoing from the additional RF that it would create. Residents and the city of Gol
Alluvial fans are triangular-shaped deposits of water-transported material referred to as alluvium. They are an example of an unconsolidated sedimentary deposit and tend to be larger and more prominent in arid to semi-arid regions; these alluvial fans form in elevated or mountainous regions where there is a rapid change in slope from a high to low gradient. The river or stream carrying the sediment flows at a high velocity due to the high slope angle, why coarse material is able to remain in the flow; when the slope decreases into a plain or plateau, the stream loses the energy it needs to move its sediment. Deposition subsequently occurs and the sediment spreads out, creating an alluvial fan. Three primary zones occur within an alluvial fan which includes the proximal fan, medial fan, the distal fan. Alluvial fans can exist on a wide spectrum of size scale. For example, alluvial fans can be on the order of only a few meters at its base and can be as large as 150 kilometers with a slope of 1.5-25 degrees.
When numerous rivers/streams converge into a single plain, the fans can combine to form a continuous apron. In arid to semi-arid environments, this is referred to as a bajada and in humid climates the continuous fan apron is called piedmont alluvial fans; as a stream's gradient decreases, it drops coarse-grained material. It makes swagger of the channel and forces it to change direction and build up a mounded or shallow conical fan shape; the deposits are poorly sorted. This fan shape can be explained with a thermodynamic justification: the system of sediment introduced at the apex of the fan will tend to a state which minimizes the sum of the transport energy involved in moving the sediment and the gravitational potential of material in the fan. There will be iso-transport energy lines forming concentric arcs about the discharge point at the apex of the fan, thus the material will tend to be deposited about these lines, forming the characteristic fan shape. The sediment that results from erosion in elevated or mountainous regions flows into the primary streams in the region where the streams act as a drainage system and carries the sediment to the alluvial plain.
Due to the high degree of slope, the river/streams are classified as straight channels. Directly at the mouth of the feeder stream in the alluvial plain, the fan is narrow and is still subjected to high energy from the high degree of slope. Once the sediment exits the feeder stream, the sediment is no longer confined to the channel walls. With this unconfinement, the sediments begin to fan out; the alluvial fan becomes wider with increasing distance from the mouth of the canyon. When there is enough space in the alluvial plain for all of the sediment deposits to fan out without contacting other valleys walls or rivers, an unconfined alluvial fan develops. Unconfined alluvial fans allow sediments to fan out and the shape of the fan is not influenced by other topological features; when the alluvial plain is narrow or short parallel to depositional flow, the fan shape is affected. The biggest natural hazard on alluvial fans are floods and debris flows. Floods on alluvial fans are flash floods: they occur with little to no warning have high velocities and sediment-transporting capability, are of short duration.
Debris flows are a type of landslide, defined as a spatially continuous moving mass of water and material, composed of coarse debris. A modern occurrence of an alluvial fan is photographed in Figure 1 in the semi-arid region between the Kunlun and Altun mountain ranges that form the southern border of the Taklamakan Desert in northwest China; this particular fan is 60 kilometers in total length and is of significance because one part of the alluvial fan is still considered active. An alluvial fan is considered active when there is still a sediment source continually feeding the fan sediment. One portion of the fan has flowing streams that are continually depositing sediment and the fan is still prograding into the alluvial plain; the feeder channels consist of straight channels as well as instances of braided channels because of the large volume of sediment sourced from the local uplands. Various environmental and geologic factors exhibit control on the deposition of alluvial fan deposits; the primary factor in alluvial fan environments is sediment supply.
The sediment that comprise the bedload and suspended load of the regional streams is sourced from the erosion of the associated highlands in the area. Therefore, a high erosion rate corresponds to an increase in sediment in the streams which affects stream morphology. For example, a high sediment load is associated with braided streams entering and within the alluvial plain. Medium to low sediment loads in the feeder stream results in straight channels.4 Alluvial fans are built in response to erosion induced by tectonic uplift to create nearby mountain ranges/highlands. This uplift is necessary for a source of erosion where the sediments are deposited in an alluvial fan regime in the alluvial plain. Tectonics can affect the degree of stream gradients and cause changes in base level which may lead to incision into fan surfaces in the distal zone of the deposit. An increase in precipitation would allow a higher water level in the streams which would allow for a greater amount of sediment to be carried along with it to be deposited in the alluvial plain.
There are three primary zones, or facies, that exist within an alluvial fan deposit which include the proximal fan, medial fan, distal fan with an overal
Mount San Antonio
Mount San Antonio, colloquially referred to as Mount Baldy, is the highest peak of the San Gabriel Mountains, the highest point in Los Angeles County, California. The peak is within Angeles National Forest, it is the tallest mountain in the Los Angeles metropolitan area. Mount San Antonio's sometimes snow-capped peaks are visible on clear days and dominate the view of the Los Angeles Basin skyline; the peak is pyramid shaped, with a shallower north face. The summit is accessible via a number of connecting ridges along hiking trails from the north, east and southwest; the mountain is always referred to as "Mount Baldy" by locals, to the point where many may not recognize the name "Mount San Antonio." The mountain was named by a local rancher after Saint Anthony of Padua. When American settlers arrived and surveyed the land, "Baldy," a reference to the bare fell-field of Baldy Bowl that dominates the south face visible from Los Angeles, became the predominant name, it has stuck. Nonetheless, "Mount San Antonio" is the official name according to the GNIS, is still used by a number of institutions.
The summit has two peaks: the main peak, elevation 10,064 feet, a sub-peak, West Baldy, at 9,988 feet. The main peak marks the boundary between Los Angeles County; the mountain is in the Angeles National Forest. The mountain's southern watershed drains into San Antonio Creek, the north side into Lytle Creek and the Fish Fork of the San Gabriel River. San Antonio and Lytle Creeks are part of the Santa Ana River watershed. San Antonio Creek descends through a deep canyon which has several waterfalls, the last about 75 feet high. East of the summit is Mount Harwood, in turn connected by a narrow ridge, "The Devil's Backbone," to a pass known as the Baldy Notch. At the Notch there is the closest one to Los Angeles. South of the resort, connected to its ski lift by an asphalt road, lies Mt Baldy Village. There are no roads or maintained trails connecting the mountain to the less populated region to its north, but a use trail leads over Dawson and Pine Mountains to Wright Mountain and the Pacific Crest Trail, overlooking the town of Wrightwood.
Mount San Antonio lies in the front range of the San Gabriel Mountains, one of the Transverse Ranges of Southern California, formed around the San Andreas Fault system. The Transverse Ranges were formed because of a dog-leg bend in the San Andreas, a transform fault; the bend makes it difficult for the two plates to move smoothly past one another, mountains were raised as a result. The prehistoric Hog Back landslide lies in the canyon of San Antonio Creek at 4000' elevation; when the slide occurred, it dammed the river, whose depth built up until the water was released catastrophically, forming a slot canyon which now holds some of the area's few good rock climbing routes. In modern times, notable floods have occurred in 1938 and 1969; the San Antonio Dam was completed in 1956, after a pause due to World War II, in an effort to prevent future floods as severe as the one in 1938, which damaged the low-elevation populated areas below. The dam succeeded in reducing the damage done by the 1969 flood.
Hydroelectric plants along San Antonio Creek are tied to the electric grid. The lower land area of the mountain consists of an ecological community known as yellow pine forest. Tree species include lodgepole pine, Jeffrey pine, white fir, some sugar pine. Limber pine occurs at the higher elevations; these forests are sparse, are intermixed with chaparral and oak savannah. Higher up, the yellow pine forest community gives way to a pure lodgepole forest. Mountain mahogany trees grow on the slopes above San Antonio Creek. Near 9000 ft these become krummholzed, beyond about 9500 ft lies an unforested subalpine zone; the dominant shrubs at the higher elevations are bush chinquapin. As the elevation increases, there is a higher ratio of chinquapin to manzanita. Other shrubs on the mountain include mountain whitethorn and mountain gooseberry. Wildflower species include Galium parishii, San Gabriel alumroot, gray monardella, pumice alpinegold, Parry's pussypaws, Nuttall's sandwort, caulanthus. There are Ross's sedge and rockcress.
Oreonana vestita, a type of mountainparsley, is adapted to talus. Desert bighorn sheep are found in the area above 7000', they lamb in the area, their population is less threatened than those of other subspecies in California. Unlike animals of this subspecies in the Mojave Desert, those in the San Gabriel Mountains cannot be hunted and need not compete with aggressive feral burros for food or water. Grizzly bears, featured on the state flag, were once common in the Transverse Ranges, but were driven to extinction in California in the late 19th century, with one of the last animals in the San Gabriels being shot in 1894 by Walter L. Richardson. Black bears did not exist in the San Gabriel Mountains, but in 1933 eleven black bears from Yosemite Valley that had shown problematic behavior were moved to Southern California and released near Crystal Lake. All black bears in the San Gabriels are believed to be descended from this group. Black bears are shy and are never known to harm humans. Rabbits and coyotes are found near San Antonio Creek at low elevations below 2000'.
The most common species of rabbits are the black-tailed jackrabbit and the desert cottontail, the jackrabbit being distinguished by its huge ears. Western gray s