The San Gabriel Wilderness is a wilderness area created in 1968 of more than 36,118 acres (150 km) within the Angeles National Forest and San Gabriel Mountains National Monument .
68-1053: The area lies on the southern slopes of the San Gabriel Mountains , between the Angeles Crest and the West Fork of the San Gabriel River . The area was originally set aside as the Devils Canyon-Bear Canyon Primitive Area of 35,000 acres (140 km). The San Gabriel Mountains were first preserved by the federal government in 1892 as the San Gabriel Timberland Reserve , established by U.S. President Benjamin Harrison and influenced by California conservationists, Abbot Kinney and John Muir . This forest reserve would later become part of
136-500: A fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth 's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults . Energy release associated with rapid movement on active faults
204-511: A $ 45 million project to reconstruct the roadway, construct soldier pile retaining walls, repair drainage systems, install rockfall protection, and provide asphalt concrete overlay and traffic striping, should begin in fall 2010." In 2011, the planned repair of the road was abruptly terminated, due to concern of high future maintenance costs, and potential impact on the local bighorn sheep population. However, in October 2016, Caltrans announced it
272-405: A fault as oblique requires both dip and strike components to be measurable and significant. Some oblique faults occur within transtensional and transpressional regimes, and others occur where the direction of extension or shortening changes during the deformation but the earlier formed faults remain active. The hade angle is defined as the complement of the dip angle; it is the angle between
340-582: A fault hosting valuable porphyry copper deposits is northern Chile's Domeyko Fault with deposits at Chuquicamata , Collahuasi , El Abra , El Salvador , La Escondida and Potrerillos . Further south in Chile Los Bronces and El Teniente porphyry copper deposit lie each at the intersection of two fault systems. Faults may not always act as conduits to surface. It has been proposed that deep-seated "misoriented" faults may instead be zones where magmas forming porphyry copper stagnate achieving
408-489: A fault plane, where it becomes locked, are called asperities . Stress builds up when a fault is locked, and when it reaches a level that exceeds the strength threshold, the fault ruptures and the accumulated strain energy is released in part as seismic waves , forming an earthquake . Strain occurs accumulatively or instantaneously, depending on the liquid state of the rock; the ductile lower crust and mantle accumulate deformation gradually via shearing , whereas
476-408: A fault's age by studying soil features seen in shallow excavations and geomorphology seen in aerial photographs. Subsurface clues include shears and their relationships to carbonate nodules , eroded clay, and iron oxide mineralization, in the case of older soil, and lack of such signs in the case of younger soil. Radiocarbon dating of organic material buried next to or over a fault shear
544-427: A hanging wall or foot wall where a thrust fault formed along a relatively weak bedding plane is known as a flat and a section where the thrust fault cut upward through the stratigraphic sequence is known as a ramp . Typically, thrust faults move within formations by forming flats and climbing up sections with ramps. This results in the hanging wall flat (or a portion thereof) lying atop the foot wall ramp as shown in
612-502: A hiker gets lost or stuck on a mountain ledge or may fall downhill. Some of the more extreme cases of emergency search-and-rescue efforts will often be given air time on Los Angeles television and radio newscasts. The Pacific Crest Trail passes along the mountain ridge. During the winter, many Southern California mountaineers climb a variety of snow routes and even some ice routes in the San Gabriel Mountains. Baldy Bowl
680-484: A major fault. Synthetic faults dip in the same direction as the major fault while the antithetic faults dip in the opposite direction. These faults may be accompanied by rollover anticlines (e.g. the Niger Delta Structural Style). All faults have a measurable thickness, made up of deformed rock characteristic of the level in the crust where the faulting happened, of the rock types affected by
748-400: A manner that creates multiple listric faults. The fault panes of listric faults can further flatten and evolve into a horizontal or near-horizontal plane, where slip progresses horizontally along a decollement . Extensional decollements can grow to great dimensions and form detachment faults , which are low-angle normal faults with regional tectonic significance. Due to the curvature of
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#1732772315385816-657: A nearly two-hour trip. Reopening Highway 39 would cut the drive-time to the Waterman Ski Area in half and shorten the trip east to Wrightwood. According to the Caltrans District Seven "Inside Seven" Newsletter, "Two projects that will address those issues and get the highway reopened are scheduled for construction soon. The first, building two retaining walls near the city of Azusa from Old San Gabriel Canyon Road to approximately 4 miles (6.4 km) south of SR-2, could begin in mid-2009. The second,
884-421: A non-vertical fault are known as the hanging wall and footwall . The hanging wall occurs above the fault plane and the footwall occurs below it. This terminology comes from mining: when working a tabular ore body, the miner stood with the footwall under his feet and with the hanging wall above him. These terms are important for distinguishing different dip-slip fault types: reverse faults and normal faults. In
952-464: A reverse fault, the hanging wall displaces upward, while in a normal fault the hanging wall displaces downward. Distinguishing between these two fault types is important for determining the stress regime of the fault movement. Faults are mainly classified in terms of the angle that the fault plane makes with the Earth's surface, known as the dip , and the direction of slip along the fault plane. Based on
1020-627: A steep, rugged and precipitous gorge. The two meet at San Gabriel Reservoir , and turn south, boring through the southern portion of the San Gabriels, emptying of the mountains near Azusa into the urban San Gabriel Valley , and eventually to the Pacific Ocean near Seal Beach . San Gabriel Mountains peaks within the Angeles National Forest include: The climate of the range varies with elevation from continental to
1088-422: Is a horst . A sequence of grabens and horsts on the surface of the Earth produces a characteristic basin and range topography . Normal faults can evolve into listric faults, with their plane dip being steeper near the surface, then shallower with increased depth, with the fault plane curving into the Earth. They can also form where the hanging wall is absent (such as on a cliff), where the footwall may slump in
1156-423: Is a zone of folding close to a fault that likely arises from frictional resistance to movement on the fault. The direction and magnitude of heave and throw can be measured only by finding common intersection points on either side of the fault (called a piercing point ). In practice, it is usually only possible to find the slip direction of faults, and an approximation of the heave and throw vector. The two sides of
1224-603: Is another notable peak, known for the Mount Wilson Observatory and the antenna farm that houses many of the transmitters for local media. The observatory may be visited by the public. On October 10, 2014, Barack Obama designated the area the San Gabriel Mountains National Monument . The Trust for Public Land has protected more than 3,800 acres (1,500 ha) of land in the San Gabriel Mountains, its foothills, and
1292-542: Is by far the most popular route, getting hundreds of climbers per season. There are many other routes, offering a variety of choices. Rock climbing is not as common in the San Gabriel Range as it is in neighboring areas, as this range is famous for loose rock. Various faults crisscross the range, making it one of the steepest and fastest-growing ranges in the world. Plate tectonic activity breaks up most rock, making it unsuitable for rock climbing. Williamson Rock
1360-544: Is defined by the direction of movement of the ground as would be seen by an observer on the opposite side of the fault. A special class of strike-slip fault is the transform fault when it forms a plate boundary. This class is related to an offset in a spreading center , such as a mid-ocean ridge , or, less common, within continental lithosphere , such as the Dead Sea Transform in the Middle East or
1428-622: Is much better, and it is open much of the winter. State Route 39 connected the city of Azusa with the Angeles Crest Highway until it was seriously damaged by landslides, first in 1978, and again in 2005. The highway was opened to emergency crews in February 2003. People heading to Mount Waterman must now travel west to Pasadena and then travel on the Angeles Crest Highway (Highway 2) in La Cañada Flintridge,
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#17327723153851496-543: Is often critical in distinguishing active from inactive faults. From such relationships, paleoseismologists can estimate the sizes of past earthquakes over the past several hundred years, and develop rough projections of future fault activity. Many ore deposits lie on or are associated with faults. This is because the fractured rock associated with fault zones allow for magma ascent or the circulation of mineral-bearing fluids. Intersections of near-vertical faults are often locations of significant ore deposits. An example of
1564-734: Is part of the Transverse Ranges and lies between the Los Angeles Basin and the Mojave Desert , with Interstate 5 to the west and Interstate 15 to the east. The range lies in, and is surrounded by, the Angeles and San Bernardino National Forests, with the San Andreas Fault as its northern border. The highest peak in the range is Mount San Antonio , commonly referred to as Mt. Baldy. Mount Wilson
1632-492: Is particularly clear in the case of detachment faults and major thrust faults . The main types of fault rock include: In geotechnical engineering , a fault often forms a discontinuity that may have a large influence on the mechanical behavior (strength, deformation, etc.) of soil and rock masses in, for example, tunnel , foundation , or slope construction. The level of a fault's activity can be critical for (1) locating buildings, tanks, and pipelines and (2) assessing
1700-775: Is prohibited, as is the use of fire-fighting tools like tractors, Phos-Chek air drops, Tovex Firebreak II explosives, and chainsaws to cut fire lines. Everything must be done by hand, even when fighting fires within the Designated Wilderness. The people who maintain hiking trails within the San Gabriel Designated Wilderness attempt to achieve a passable hiking experience within the wilderness that does not appear to be too greatly unnatural. To achieve such an effect, tree limbs and branches that must be cut back are finished with an effort to appear natural, bucked tree trunks that are removed from
1768-509: Is prohibited, requiring the use of crosscut saws , block-and-tackle chains and ropes to pull trees off of trails, griphoists, and other mechanical tools which do not produce noise or petroleum-based pollutants. In addition, wheeled tools and equipment are not permitted to be used in the Designated Wilderness, neither for trail maintenance nor for recreation, causing the wilderness to be classified for pedestrian and equestrian use only with mountain biking prohibited. Blasting to remove rock outcrops
1836-425: Is the cause of most earthquakes . Faults may also displace slowly, by aseismic creep . A fault plane is the plane that represents the fracture surface of a fault. A fault trace or fault line is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A fault zone is a cluster of parallel faults. However,
1904-762: The Alpine Fault in New Zealand. Transform faults are also referred to as "conservative" plate boundaries since the lithosphere is neither created nor destroyed. Dip-slip faults can be either normal (" extensional ") or reverse . The terminology of "normal" and "reverse" comes from coal mining in England, where normal faults are the most common. With the passage of time, a regional reversal between tensional and compressional stresses (or vice-versa) might occur, and faults may be reactivated with their relative block movement inverted in opposite directions to
1972-623: The Arroyo Seco , a tributary of the Los Angeles River . Southeast of Big Tujunga Canyon, the southern front range of the San Gabriels gradually grows in elevation, culminating in notable peaks such as Mount Wilson at 5,710 feet (1,740 m). On the north the range is abruptly dissected by the canyon of the West Fork San Gabriel River. Even further north the range slopes up into the towering main crest of
2040-554: The Santa Susana Mountains at Newhall Pass (Interstate 5). South and east of Santa Clarita and north of San Fernando , the San Gabriel Mountains crest abruptly up to about 4,000 feet (1,200 m). Pacoima and Big Tujunga Canyons cut through the range just east of San Fernando, carrying runoff into the San Fernando Valley . Little Tujunga Canyon Road bridges the range in this area, connecting
2108-651: The Victor Valley and the western Cajon Valley. Past its junction with Angeles Forest Highway, traveling east, Angeles Crest Highway features blind curves, various bumps, and potholes. This section of the "Crest" is closed during the winter due to rockfall and avalanche hazards. State Route 2, just past Mountain High , is called the Big Pines Highway to the Route 138 junction. Another key county route through,
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2176-657: The seismic shaking and tsunami hazard to infrastructure and people in the vicinity. In California, for example, new building construction has been prohibited directly on or near faults that have moved within the Holocene Epoch (the last 11,700 years) of the Earth's geological history. Also, faults that have shown movement during the Holocene plus Pleistocene Epochs (the last 2.6 million years) may receive consideration, especially for critical structures such as power plants, dams, hospitals, and schools. Geologists assess
2244-550: The Angeles National Forest in which the San Gabriel Wilderness is now located. Permits are not required to enter the San Gabriel wilderness. The following trails provide access: Hiking trails in the Designated Wilderness are built and maintained utilizing hand tools and materials which are strictly limited in terms of environmental impact. The use of chainsaws to remove trees that are down across trails
2312-601: The Angeles National Forest. Much of the range features rolling peaks. The range lacks craggy features, but contains a large number of canyons and is generally very rugged and difficult to traverse. The San Gabriel Mountains are composed of a large fault block between the San Andreas Fault Zone to the north, and the San Gabriel Fault and the Sierra Madre and Cucamonga Fault Zones to
2380-665: The Mediterranean, with mostly dry summers (except for scattered summer thunderstorms) and cold, wet winters. Snow can fall above 4,000 ft (1,200 m) elevation during frontal passages between November and April, but is most common in December through March. Annual precipitation totals are mostly in excess of 25 in (640 mm) on the coastal (southern) slopes above 3,000 ft (900 m) elevation, with up to 45 in (1,100 mm) falling in some areas above 5,000 ft (1,500 m). The coastal (south) side of
2448-472: The Mojave. To the east, the San Andreas Fault cuts across the range, forming a series of long, straight, and narrow depressions, including Swarthout Valley and Lone Pine Canyon. South of Mount San Antonio, San Antonio Creek drains the mountains, cutting the deep San Antonio Canyon. East of San Antonio Canyon, the range gradually loses elevation, and the highest peaks in this section of the mountain range are in
2516-616: The North American west coast. Like nearly all of the other mountains in the Transverse Ranges , the San Gabriels are a series of fault blocks that were uplifted in the Cenozoic . Tectonic uplift rates and erosion rates systematically increase as topography steepens eastward in the San Gabriel Mountains, where the San Andreas and San Jacinto faults meet. Current rates of erosion in the eastern San Gabriel mountains are among
2584-622: The San Andreas Fault produces numerous springs, sag ponds, and wetland areas that are critical habitats for a variety of native species. Larger animals include California mule deer , California black bear , San Pedro Martir coyote and the rarely seen mountain lion or cougar. Smaller mammals include raccoons, opossum, skunk, and bobcats. Golden and bald eagles are found rarely, but hawks are common. Rattlesnakes are common and often encountered on trails by hikers. Critically endangered yellow-legged frogs have declined or vanished from
2652-558: The San Fernando Valley to the Santa Clara River valley in the north. Towering over Big Tujunga Canyon north of Big Tujunga Reservoir , and south of Acton, is Mount Gleason, which at 6,502 feet (1,982 m), is the highest in this region of the San Gabriels. South of the gorge is the southern "foothills" of the mountains, which rise abruptly 4,000 feet (1,200 m) above the Los Angeles Basin and give rise to
2720-418: The San Gabriels, a sweeping arc-shaped massif 30 miles (48 km) in length that includes most of the highest peaks in the range: Waterman Mountain , at 8,038 feet (2,450 m); Mount Islip , at 8,250 feet (2,510 m), Mount Baden-Powell , at 9,399 feet (2,865 m), Pine Mountain , at 9,648 feet (2,941 m), and Mount San Antonio , the highest peak in the range at 10,068 feet (3,069 m). On
2788-403: The brittle upper crust reacts by fracture – instantaneous stress release – resulting in motion along the fault. A fault in ductile rocks can also release instantaneously when the strain rate is too great. Slip is defined as the relative movement of geological features present on either side of a fault plane. A fault's sense of slip is defined as the relative motion of the rock on each side of
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2856-436: The direction of slip, faults can be categorized as: In a strike-slip fault (also known as a wrench fault , tear fault or transcurrent fault ), the fault surface (plane) is usually near vertical, and the footwall moves laterally either left or right with very little vertical motion. Strike-slip faults with left-lateral motion are also known as sinistral faults and those with right-lateral motion as dextral faults. Each
2924-848: The even higher San Bernardino Mountains . The Range is bounded on the north by the Antelope Valley and the Mojave Desert and to the south by the communities of Greater Los Angeles . The south side of the range is almost continuously urbanized and includes the Los Angeles city communities of Sylmar , Pacoima , and Sunland-Tujunga , as well as cities and unincorporated areas of San Fernando , La Crescenta , La Cañada Flintridge , Altadena , Pasadena , Sierra Madre , Arcadia , Monrovia , Bradbury , Duarte , Azusa , Glendora , San Dimas , La Verne , Claremont , Upland , Rancho Cucamonga , Fontana , and Rialto . The north side of
2992-467: The fastest in the continental United States and have accelerated in response to the increased frequency of wildfires over the 1900s. Over future centuries, it remains unclear whether soil and brush ecosystems in the San Gabriel mountains will continue to re-establish soil and vegetation after increasing fire and soil-erosion frequencies, or if increasing fire frequencies and erosion will strip soils and permanently alter soil cover and vegetation types across
3060-456: The fault and of the presence and nature of any mineralising fluids . Fault rocks are classified by their textures and the implied mechanism of deformation. A fault that passes through different levels of the lithosphere will have many different types of fault rock developed along its surface. Continued dip-slip displacement tends to juxtapose fault rocks characteristic of different crustal levels, with varying degrees of overprinting. This effect
3128-402: The fault concerning the other side. In measuring the horizontal or vertical separation, the throw of the fault is the vertical component of the separation and the heave of the fault is the horizontal component, as in "Throw up and heave out". The vector of slip can be qualitatively assessed by studying any drag folding of strata, which may be visible on either side of the fault. Drag folding
3196-576: The fault plane and a vertical plane that strikes parallel to the fault. Ring faults , also known as caldera faults , are faults that occur within collapsed volcanic calderas and the sites of bolide strikes, such as the Chesapeake Bay impact crater . Ring faults are the result of a series of overlapping normal faults, forming a circular outline. Fractures created by ring faults may be filled by ring dikes . Synthetic and antithetic are terms used to describe minor faults associated with
3264-401: The fault plane, the horizontal extensional displacement on a listric fault implies a geometric "gap" between the hanging and footwalls of the fault forms when the slip motion occurs. To accommodate into the geometric gap, and depending on its rheology , the hanging wall might fold and slide downwards into the gap and produce rollover folding , or break into further faults and blocks which fil in
3332-427: The fault-bend fold diagram. Thrust faults form nappes and klippen in the large thrust belts. Subduction zones are a special class of thrusts that form the largest faults on Earth and give rise to the largest earthquakes. A fault which has a component of dip-slip and a component of strike-slip is termed an oblique-slip fault . Nearly all faults have some component of both dip-slip and strike-slip; hence, defining
3400-475: The gap. If faults form, imbrication fans or domino faulting may form. A reverse fault is the opposite of a normal fault—the hanging wall moves up relative to the footwall. Reverse faults indicate compressive shortening of the crust. A thrust fault has the same sense of motion as a reverse fault, but with the dip of the fault plane at less than 45°. Thrust faults typically form ramps, flats and fault-bend (hanging wall and footwall) folds. A section of
3468-495: The mountain ecosystem. There are both areas of conifer as well as broadleaf forestation, including the presence of some endemic taxa. Conifer (pine, fir, cedar) and oak forests are most widespread above 5,000 feet (1,500 m) where the precipitation is above 30 inches (760 mm) (the central and eastern high San Gabriels). In the wetter areas, madrone and bay laurel trees also occur in places, and ferns are common. Trees like willow, alder, and cottonwood are also found throughout
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#17327723153853536-566: The mountains during big storms often produces flooding in adjacent foothill communities (especially in areas denuded by wildfires). The range is mostly smog-free above 5,000 ft (1,500 m) elevation, above the inversion layer. The large telescope installation at Mt. Wilson is a testimony to the clear atmospheric conditions that prevail, although light pollution from the L.A. basin below has hindered telescope activities in recent decades. The San Gabriel Mountains see wildfires frequently. The fires are often driven by dry Santa Ana wind events in
3604-425: The mountains is Angeles Forest Highway . Angeles Forest Highway begins 11 miles northeast of La Cañada Flintridge at its Angeles Crest Highway junction. Ending near Acton , it allows easy access to the central Forest and the fast-growing Antelope Valley . Because the "Forest" and the 11-mile (18 km) "Crest" portion leading to La Cañada Flintridge is well-traveled by Antelope Valley commuters, its road maintenance
3672-451: The north slopes of the San Gabriel crest, the northern ranks of mountains drop down incrementally to the floor of the Mojave Desert in a much more gradual manner than the sheer southern flank. The Angeles Crest Highway , one of the main routes across the San Gabriels, runs through this area from west to east. Little Rock, Big Rock, and Sheep Creeks drain off the northern part of the mountains, forming large alluvial fans as they descend into
3740-500: The original movement (fault inversion). In such a way, a normal fault may therefore become a reverse fault and vice versa. In a normal fault, the hanging wall moves downward, relative to the footwall. The dip of most normal faults is at least 60 degrees but some normal faults dip at less than 45 degrees. A downthrown block between two normal faults dipping towards each other is a graben . A block stranded between two grabens, and therefore two normal faults dipping away from each other,
3808-493: The range along with the stream courses (riparian habitat), even at lower elevations. Chaparral (dense shrub, brush, and small tree) vegetation is widespread where there is no continuous tall tree cover, especially at lower elevations. Chaparral is highly adapted to fire and replaces trees for decades after fires. There is a subspecies of the Leather Oak which is found only within the San Gabriel Mountains. The Rift Zone along
3876-437: The range is less densely populated and includes the city of Palmdale as well as the small unincorporated towns of Acton , Littlerock , Pearblossom , Valyermo , Llano , Piñon Hills , and Phelan . At the west end of the range lies the city of Santa Clarita . Within the mountains themselves are the small unincorporated communities of Mount Baldy , Wrightwood , Big Pines and Lytle Creek . Melting snow and rain runoff on
3944-417: The range receives more precipitation than the desert (northern) side. The highest precipitation is found in the central and eastern parts of the range (Mt. Wilson to Mt. San Antonio). Annual precipitation totals are highly variable from year to year, and can be extremely high during wet El Nino years (sometimes over 70 in (1,800 mm), with single storm totals over 10 in (250 mm)). Runoff from
4012-412: The right time for—and type of— igneous differentiation . At a given time differentiated magmas would burst violently out of the fault-traps and head to shallower places in the crust where porphyry copper deposits would be formed. As faults are zones of weakness, they facilitate the interaction of water with the surrounding rock and enhance chemical weathering . The enhanced chemical weathering increases
4080-497: The south side of the San Gabriels' highest mountains give rise to its largest river, the San Gabriel River . Just to the west of Mount Hawkins , a north-south divide separates water running down the two main forks of the river and their tributaries. The West Fork, beginning at Red Box Saddle, runs 14 miles (23 km) eastward, and the East Fork, starting north of Mount San Antonio, flows 18 miles (29 km) south and west through
4148-506: The south, rising dramatically above the cities of Claremont , Upland and Rancho Cucamonga . However, there are still several notable peaks in this region, including Telegraph Peak , at 8,985 feet (2,739 m), Cucamonga Peak , at 8,859 feet (2,700 m), and Ontario Peak , rising 8,693 feet (2,650 m). Lytle Creek , flowing generally southeast, drains most of the extreme eastern San Gabriels. The range terminates at Cajon Pass, through which runs Interstate 15 , and beyond which rise
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#17327723153854216-705: The south. This tectonic block was uplifted during the Miocene and has since been dissected by numerous rivers and washes. The highest elevation, Mount San Antonio (Mount Baldy) at 10,069 feet (3,069 m), rises towards the eastern extremity of the range which extends from the Cajon Pass (Interstate 15) on the east, where the San Gabriel Mountain Range meets the San Bernardino Mountain Range , westward to meet
4284-477: The streams due to the loss of suitable habitat. The introduction of invasive predators like trout, which feed on tadpoles, decimated their population. The main road that runs through the San Gabriel Mountains is the Angeles Crest Highway , State Route 2 . It starts in the southwest at the city of La Cañada Flintridge and ends at its junction with State Route 138 , just past Wrightwood , near
4352-544: The summer and fall. Notable wildfires in the San Gabriel Mountains have included the 2009 Station Fire , 2020 Bobcat Fire , and the 2024 Bridge Fire . Granitic and metasedimentary rocks are the primary constituent of the San Gabriel Mountains. Metasedimentary rocks were attached to the North American craton in the Precambrian eon, and granitic rocks formed throughout the Mesozoic as oceanic plates subducted underneath
4420-468: The term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the distinction, as the rock between the faults is converted to fault-bound lenses of rock and then progressively crushed. Due to friction and the rigidity of the constituent rocks, the two sides of a fault cannot always glide or flow past each other easily, and so occasionally all movement stops. The regions of higher friction along
4488-441: The trail are relocated so that they appear at a distance and do not look to have been cut by people, and even sawdust from crosscut saws will be collected and buried off of the trail. San Gabriel Mountains The San Gabriel Mountains ( Spanish : Sierra de San Gabriel ) comprise a mountain range located in northern Los Angeles County and western San Bernardino County, California , United States. The mountain range
4556-453: Was again considering plans to re-open the road, after pressure from local communities. In the winter, snowboarding and skiing are quite popular in the San Gabriels, at Mountain High and Mt. Baldy . The two other resorts, Mount Waterman and Kratka Ridge , are rarely open due to insufficient snow. In the summer, canyoneering , hiking, backpacking, picnicking, and camping are some of the activities popular with visitors. From time to time,
4624-479: Was the most famous climbing area until it was closed for climbing. There are many other craggy areas scattered about the range that provide mostly traditional climbing opportunities. Angeles National Forest Fire Lookout Association has rebuilt and operates Vetter Mountain Lookout , and Slide Mountain Lookout . The organization is rebuilding South Mount Hawkins Lookout . Fault (geology) In geology ,
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