Mount Diablo
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Mount Diablo is a mountain of the Diablo Range, in Contra Costa County of the eastern San Francisco Bay Area in Northern California. It is south of Clayton and northeast of Danville. It is an isolated upthrust peak of , visible from most of the San Francisco Bay Area. Mount Diablo appears from many angles to be a double pyramid and has many subsidiary peaks. The largest and closest is North Peak, the other half of the double pyramid, which is nearly as high in elevation at , and is about northeast of the main summit. The mountain is within the boundaries of Mount Diablo State Park, which is administered by
California State Parks The California Department of Parks and Recreation, more commonly known as California State Parks, manages the California state parks system. The system administers 279 separate park units on 1.4 million acres (570,000 hectares), with over 280 ...
.


Geography

The summit is accessible by foot, bicycle, or motor vehicle. Road access is via North Gate Road or South Gate Road. Also you can hike in various places in Mount Diablo.


Mount Diablo State Park

The peak is in Mount Diablo State Park, a state park of about . The state park was the first public open space established on or near the peak. According to the non-profit Save Mount Diablo, there are now varied types of protected lands on and around Mount Diablo that total more than . These include 38 preserves, such as nearby city open spaces, regional parks, and watersheds, which are buffered in some areas with private lands that have been protected by conservation easements. The day use fee per vehicle for the park varies according to the entrance: $6 via Macedo Ranch (Alamo) or Mitchell Canyon (Clayton), and $10 via South Gate Rd. (Danville) & North Gate Rd. (Walnut Creek) leading up Mount Diablo. -->


Viewshed

On a clear day, the Sierra Nevada range is plainly visible from the summit. The best views are after a winter storm; a snowy Sierra shows up better, and summer days are likely to be hazy.
Lassen Peak Lassen Peak ( ), commonly referred to as Mount Lassen, is a lava dome volcano and the southernmost active volcano in the Cascade Range of the Western United States. Located in the Shasta Cascade region of Northern California, it is part of the ...
, away, is occasionally just visible over the curve of the earth.
Sentinel Dome Sentinel Dome is a granite dome in Yosemite National Park, United States. It lies on the south wall of Yosemite Valley, southwest of Glacier Point and northeast of Profile Cliff. Sentinel Dome is known for a Jeffrey Pine that grew from its pea ...
in Yosemite National Park is visible, but Half Dome is hidden by the 8000-foot ridge at 37.755N 119.6657W. Eight bridges are visible, from left to right (southwest to northeast): San Mateo, Bay,
Golden Gate The Golden Gate is a strait on the west coast of North America that connects San Francisco Bay to the Pacific Ocean. It is defined by the headlands of the San Francisco Peninsula and the Marin Peninsula, and, since 1937, has been spanned by t ...
, San Rafael, Carquinez, Benicia, Antioch, and Rio Vista. Claims that the mountain's
viewshed A viewshed is the geographical area that is visible from a location. It includes all surrounding points that are in line-of-sight with that location and excludes points that are beyond the horizon or obstructed by terrain and other features (e.g. ...
is the largest in the worldor second largest after Mount Kilimanjaroare ill-founded. It does boast one of the largest viewsheds in the Western United States and played a key role in California history. Countless peaks in the state are taller, but Mount Diablo has a remarkable visual prominence for a mountain of such low elevation. Its looming presence over much of the Bay Area, delta, and Central Valley, and good visibility even from the Mother Lode, all key regions during the gold rush and early statehood, made it an important landmark for mapping and navigation. The summit is used as the reference datum for land surveying in much of northern California and Nevada.


Cultural history

Mount Diablo is sacred to many California Native American peoples. According to
Miwok mythology The mythology of the Miwok Native Americans are myths of their world order, their creation stories and 'how things came to be' created. Miwok myths suggest their spiritual and philosophical world view. In several different creation stories collec ...
and Ohlone mythology, it was the point of creation. The local peoples of the area traditionally had a variety of creation narratives associated with the mountain. In one surviving narrative fragment, Mount Diablo and Reed's Peak ( Mount Tamalpais) were surrounded by water; from these two islands the creator Coyote and his assistant Eagle-man made Native American people and the world. In another, Molok the Condor brought forth his grandson Wek-Wek the Falcon Hero, from within the mountain.


Earliest names

About 25 independent tribal groups with well-defined territories lived in the East Bay countryside surrounding the mountain. Their members spoke dialects of three distinct languages: Ohlone, Bay Miwok, and Northern Valley Yokuts. The Chochenyo-speaking Ohlone from Mission San Jose and the East Bay area, called the mountain , meaning "at the dawn of time". Further inland, the
Nisenan The Nisenan are a group of Native Americans and an Indigenous people of California from the Yuba River and American River watersheds in Northern California and the California Central Valley. The Nisenan people are classified as part of the lar ...
of the Sacramento Valley called it , "dog mountain"; because, as Nisenan elder Dalbert Castro once explained, it's "the place where dogs came from in trade". A Southern Sierra Miwok name for the mountain was , and a Northern Sierra Miwok name was . It has also been suggested that another early Native American name for the mountain was or , but there is no evidence to confirm the assertion. According to Indian historian Bev Ortiz and Save Mount Diablo: "The name was made up in 1866 — with no real Native American connection — referred to the California Legislature's Committee on Public Morals, and tabled. It resurfaced as a real estate gimmick in 1916 with a supposed new translation, "Laughing Mountain", attributed without documentation to Diablo area Volvon Indians. explains the mountain's naming and debunks the name "Kahwookum" as fictitious. Most of Mount Diablo, including its peak, was within the homeland of the early Volvon (sometimes spelled Wolwon, Bolbon or Bolgon), a Bay Miwok–speaking tribe. As early as 1811, Spanish colonists referred to the mountain as ("High Hill of the Volvon") or sometimes . This name persisted for awhile but was replaced in 1850 by the Americans.


Current name

The conventional view is that the peak derives its name from the reaction of Spanish soldiers to the 1805 escape of several Chupcan Native Americans in a willow thicket some 7 miles north of the mountain. One story tells that their nighttime escape through the thicket was aided by mysterious lights. An 1850 report by General Mariano G. Vallejo tells of a strange dancing spirit turning the battle in favor of the Chupcan. Vallejo interpreted the natives' word for the personage, , to mean "devil" in the Anglo-American language. Vallejo's report could be interpreted to align with Edward G. Gudde's history of place names. (Kyle, and Ortiz) By 1824, the region north of the mountain came to be known as ''Monte del Diablo'' ("devil's thicket"; in this case ''monte'' should be translated as thicket or dense woods). It was shown on maps near present-day Concord (formerly known as
Pacheco Pacheco is a Portuguese and Spanish name which may refer to: General * Alex Pacheco (born 1958), animal rights activist, co-founder of PETA. *Ángel Pacheco (general) (1793-1869), was an Argentine military officer trained by José de San Martín ...
). Later, U.S. settlers understood "Monte" to refer directly to the mountain, and it was recorded with varying degrees of certainty until "Mount Diablo" became official in 1850. In May 1862, California Geological Survey field director William H. Brewer named the northeast peak of Mount Diablo "Mount King," after Rev. Thomas Starr King, a Unitarian clergyman, abolitionist, Republican, Yosemite advocate, cultural Unionist, and California's leading intellectual. Today it is known simply as North Peak.


Mount Diablo

In 2005 Arthur Mijares, from the neighboring town of Oakley, petitioned the federal government to change the name of the mountain, claiming it offended his Christian beliefs. Additionally, he claimed that Diablo is a living person, and so is banned under federal law. He suggested renaming the mountain Mount Kawukum, and later, Mount Yahweh. Suggestions by other individuals included Mount Miwok and Mount Ohlone, after local Indian tribes. Finally Mijares proposed Mount Reagan, but the board rejected it on the grounds that a person must be deceased for five years to have a geographic landmark named after them. Eventually, the U.S. Board on Geographic Names rejected the petitions, saying there was no compelling reason to change the name. In 2009 Mijares again proposed the name Mount Reagan to the United States Board of Geographic Names because the late president was by then eligible. The board gave the Contra Costa County Supervisor's Committee until March 31 to file an opinion. Individual members of the committee have responded that although they respect Reagan, Mount Reagan is not an appropriate name for the historic mountain. Later, the board unanimously voted against renaming the mountain, citing its historical significance.


Early uses

In 1851 the south peak of the mountain was selected by Colonel Leander Ransom as the initial point—where the Mount Diablo Base and Mount Diablo Meridian lines intersect—for
cadastral A cadastre or cadaster is a comprehensive recording of the real estate or real property's metes-and-bounds of a country.Jo Henssen, ''Basic Principles of the Main Cadastral Systems in the World,'/ref> Often it is represented graphically in a cad ...
surveys of a large area. Subsequent surveys in much of California, Nevada and Oregon were located with reference to this point.
Toll road A toll road, also known as a turnpike or tollway, is a public or private road (almost always a controlled-access highway in the present day) for which a fee (or ''Toll (fee), toll'') is assessed for passage. It is a form of road pricing typically ...
s up the mountain were created in 1874 by Joseph Seavey Hall and William Camron (sometimes "Cameron"); Hall's Mount Diablo Summit Road was officially opened on May 2, 1874. Camron's "Green Valley" road opened later. Hall also built the 16-room Mountain House Hotel near the junction of the two roads, a mile below the summit (2,500 foot elevation. (It operated through the 1880s, was abandoned in 1895, and burned c. 1901). As far north as Meridian Road, on the outskirts of
Chico, California Chico ( ; Spanish for "little") is the most populous city in Butte County, California. Located in the Sacramento Valley region of Northern California, the city had a population of 101,475 in the 2020 census, reflecting an increase from 86,18 ...
, the summit was used as a reference point. The road is colinear with the summit, and is named for the meridian which intersects it. An aerial navigation beacon, the Standard Diablo tower, was erected by Standard Oil at the summit in 1928. The 10-million-candlepower beacon became known as the "Eye of Diablo" and was visible for a hundred miles.


Protection of the area

After initial legislation in 1921, the state of California acquired enough land in 1931 to create a small state park around the peak. Many improvements were carried out in the 1930s by the Civilian Conservation Corps, but park expansion slowed in the 1940s through the 1960s. Significantly, botanist Mary Leolin Bowerman (1908–2005), founder of the Save Mount Diablo non-profit in 1971, published her Ph.D. dissertation in 1936 at the
University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...
. In 1944 she published her book, ''The Flowering Plants and Ferns of Mount Diablo, California''. Her study boundaries became the basis for the state park's first map and for the park's eventual expansion. Her work also became the origin of many of the park's place names. Mount Diablo was used for broadcasting purposes in the 1950s by radio station KSBR-FM and television station KOVR (channel 13). The Mount Diablo site gave KOVR, which was based in Stockton, regional coverage that also included San Francisco and Sacramento. However, it also forced the station to pay San Francisco rates for movies and impeded any attempt at obtaining network affiliation. In 1957, the station relocated to Butte Mountain in
Jackson Jackson may refer to: People and fictional characters * Jackson (name), including a list of people and fictional characters with the surname or given name Places Australia * Jackson, Queensland, a town in the Maranoa Region * Jackson North, Qu ...
in order to become an ABC affiliate and remove its signal from the Bay Area. This state park has been greatly expanded over the decades. Soon after Earth Day in 1971, the nonprofit organization "Save Mount Diablo" was created by co-founders Mary Bowerman and Art Bonwell, barely ahead of real estate developers. At the time, the state park included just and was the only park in the vicinity of the mountain. In 2007 the state park totaled almost , and with 38 parks and preserves on and around the mountain, Diablo's public lands total more than . According to Save Mount Diablo, there are 50 individual preserves on and around Mount Diablo, some of which are conservation easements covering a single parcel, others are expected to eventually be absorbed into larger nearby parks. As of December 2007, the organization recognizes 38 specific Diablo parks and preserves. The State Park adjoins park lands of the East Bay Regional Park District, including Morgan Territory Regional Preserve, Brushy Peak Regional Preserve, Vasco Caves Regional Preserve, and Round Valley Regional Preserve. It also adjoins protected areas owned or controlled by local cities such as the Borges Ranch Historic Farm, the
Concord Naval Weapons Station Concord Naval Weapons Station was a military base established in 1942 north of the city of Concord, California at the shore of the Sacramento River where it widens into Suisun Bay. The station functioned as a World War II armament storage depot ...
(now in the process of being converted to non military use), Indian Valley, Shell Ridge Open Space and
Lime Ridge Open Space Lime commonly refers to: * Lime (fruit), a green citrus fruit * Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide * Lime (color), a color between yellow and green Lime may also refer to: Botany ...
s near city of Walnut Creek, and east to the
Los Vaqueros Reservoir The Los Vaqueros Reservoir and watershed is located in the northern Diablo Range, within northeastern Contra Costa County, northern California. It was completed by the Contra Costa Water District (CCWD) in to improve the quality of drinking water ...
watershed. The new Marsh Creek State Park and
Black Diamond Mines Regional Preserve The Black Diamond Mines Regional Preserve is a park located north of Mount Diablo in Contra Costa County, California under the administration of the East Bay Regional Park District (EBRPD). The district acquired the property in 1973. The preser ...
are among the open spaces stretching to the north. In this way the open spaces controlled by cities, the East Bay Regional Park District, Mount Diablo State Park, and various regional preserves now adjoin and protect much of the elevated regions of the mountain. There are unprotected areas in Arroyo del Cerro, Curry Canyon, the Marsh creek region, and on the northern slopes of North Peak, and in a number of inholdings surrounded by preserve land. Park expansion continues on all sides of the mountain although its western boundaries are largely complete. Extensive development continues in the southwestern foothills and Tassajara region, such as the upscale development of
Blackhawk Black Hawk and Blackhawk may refer to: Animals * Black Hawk (horse), a Morgan horse that lived from 1833 to 1856 * Common black hawk, ''Buteogallus anthracinus'' * Cuban black hawk, ''Buteogallus gundlachii'' * Great black hawk, ''Buteogallus uru ...
and individual estates overlooking the Livermore Valley on Morgan Territory Road. Other large projects are proposed in the northern Black Diamond Mines and Los Medanos foothills, at the Concord Naval Weapons Station, and near Cowell Ranch State Park. Large-scale development of other private parcels is restricted by city and county urban limit lines, by lack of water, excessive slope, and sensitive resources including rare species. Development of smaller ranchette subdivisions continue to fragment and threaten many parcels and large areas of habitat.


Map of protected lands

In 2007 Save Mount Diablo published ''Mount Diablo, Los Vaqueros & Surrounding Parks, Featuring the Diablo Trail'', the most accurate and up-to-date map of Mount Diablo's more than of protected lands. It includes 100 access points, of trail, and of private fire roads. Updated acreages and trail mileages were discussed in accompanying press materials and news articles.


Natural history


Geology

Mount Diablo is a geologic anomaly about east of San Francisco. The mountain is the result of geologic compression and uplift caused by the movements of the Earth's plates. The mountain lies between converging earthquake faults and continues to grow slowly. While the principal faults in the region are of the strike-slip type, a significant thrust fault (with no surface trace) is found on the mountain's southwest flank. The uplift and subsequent weathering and erosion have exposed ancient oceanic Jurassic and Cretaceous age rocks that now form the summit. The mountain grows from three to five millimeters each year. The upper portion of the mountain is made up of volcanic and sedimentary deposits of what once was one or more island arcs of the
Farallon Plate The Farallon Plate was an ancient oceanic plate. It formed one of the three main plates of Panthalassa, alongside the Phoenix Plate and Izanagi Plate, which were connected by a triple junction. The Farallon Plate began subducting under the west ...
dating back to the Jurassic and Cretaceous periods, between 90 and 190 million years ago. During this time, the
Farallon Plate The Farallon Plate was an ancient oceanic plate. It formed one of the three main plates of Panthalassa, alongside the Phoenix Plate and Izanagi Plate, which were connected by a triple junction. The Farallon Plate began subducting under the west ...
was subducting beneath the North American continent. These deposits were scraped off the top and accreted onto the North American Plate. This resulted in the highly distorted and fractured basalt and serpentine of the Mount Diablo Ophiolite and metasediments of the
Franciscan Complex The Franciscan Complex or Franciscan Assemblage is a geologic term for a late Mesozoic terrane of heterogeneous rocks found throughout the California Coast Ranges, and particularly on the San Francisco Peninsula. It was named by geologist Andrew ...
around the summit. East of the subduction zone, a basin was filling with sediment from the ancestral Sierra further to the east. Up to 60,000 feet (18,000 m) of sandstone, mudstone, and limestone of the Great Valley Sequence were deposited from 66 to 150 million years ago. These deposits are now found faulted against the Ophiolite and Franciscan deposits. Over the past 20 million years continental deposits have been periodically laid down and subsequently jostled around by the newly formed San Andreas Fault system, forming the Coast Ranges. Within the last four million years, local faulting has resulted in compression, folding, buckling, and erosion, bringing the various formations into their current juxtaposition. This faulting action continues to change the shape of Mount Diablo, along with the rest of the Coast Ranges. The summit area of Mount Diablo is made up of deposits of gray sandstone,
graywacke Greywacke or graywacke (German ''grauwacke'', signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or lit ...
, chert, oceanic volcanic
basalts Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of ...
(greenstone) and a minor amount of shale. The hard red Franciscan chert is sedimentary in origin and rich in microscopic
radiolaria The Radiolaria, also called Radiozoa, are protozoa of diameter 0.1–0.2 mm that produce intricate mineral skeletons, typically with a central capsule dividing the cell into the inner and outer portions of endoplasm and ectoplasm. The el ...
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
s. In the western foothills of the mountain there are large deposits of younger sandstone rocks also rich in seashells, severely tilted and in places forming dramatic ridgelines. Mount Diablo forms a double pyramid which gives the appearance of a volcano although in fact it is formed of ancient sea floor rock being uplifted by relatively recent tectonic forces. Deposits of glassmaking-grade sand and lower-quality coal north of the mountain were mined in the 19th and early 20th centuries, but are now open to visitors as the
Black Diamond Mines Regional Preserve The Black Diamond Mines Regional Preserve is a park located north of Mount Diablo in Contra Costa County, California under the administration of the East Bay Regional Park District (EBRPD). The district acquired the property in 1973. The preser ...
. Guided tours of the sand mines and coal field are provided.


Vegetation

The park's vegetation is mixed oak woodland and savannah and open grassland with extensive areas of chaparral and a number of endemic plant species, such as the Mount Diablo manzanita (''Arctostaphylos auriculata''), Mount Diablo fairy-lantern (''Calochortus pulchellus''), chaparral bellflower (''Campanula exigua''), Mount Diablo bird's beak (''Cordylanthus nidularius''), and Mount Diablo sunflower (''Helianthella castanea''). The park includes substantial thickets, isolated examples, and mixed ground cover of western poison oak. (It is best to learn the characteristics of this shrub and its toxin before hiking on narrow trails through brush and to be aware that it can be bare of leaves (but toxic to contact) in the winter.) At higher altitudes and on north slopes is the widely distributed foothill pine (''Pinus sabiniana''). Knobcone pine (''Pinus attenuata'') may be found along Knobcone Pine Road in the southern part of the park. The park and nearby
Black Diamond Mines Regional Preserve The Black Diamond Mines Regional Preserve is a park located north of Mount Diablo in Contra Costa County, California under the administration of the East Bay Regional Park District (EBRPD). The district acquired the property in 1973. The preser ...
mark the northern extreme of the range of
Coulter pine The Coulter pine or big-cone pine, ''Pinus coulteri'', is a native of the coastal mountains of Southern California in the United States and northern Baja California in Mexico. Isolated groves are found as far north as Clearlake, California on the ...
(''Pinus coulteri''). This species may be seen along the Coulter Pine Trail near the north (Mitchell Canyon) entrance. In 2005 the endangered species Mount Diablo buckwheat (''Eriogonum truncatum''), thought to be extinct since last seen in 1936, was rediscovered in a remote area of the mountain. File:Pinus sabineana 00057.JPG, This '' Pinus sabiniana'' (foothill pine), the most common tree species in the park, is dwarfed by harsh conditions near the summit of Mount Diablo. File:Pedicularis densiflora mt. diablo.JPG, '' Pedicularis densiflora'' File:ARctostaphylos auriculata at Mt. Diablo - Flickr - theforestprimeval (15).jpg, ''
Arctostaphylos auriculata ''Arctostaphylos auriculata'' (Mount Diablo manzanita) is an endangered species of ''Arctostaphylos'' endemic to California, and limited in geography to the area surrounding Mount Diablo, in Contra Costa County. Description ''Arctostaphylos auri ...
'' File:Juniperus californica Mount Diablo.jpg, '' Juniperus californica'' File:Western wallflower.jpg, '' Erysimum capitatum'' File:Valley Oak Mount Diablo.jpg, ''
Quercus lobata ''Quercus lobata'', commonly called the valley oak or roble, grows into the largest of California oaks. It is endemic to California, growing in interior valleys and foothills from Siskiyou County to San Diego County. Mature specimens may attain ...
'' File:Delphinium nudicaule.jpg, '' Delphinium nudicaule''


Wildlife

All vegetation, minerals and wildlife within the park are protected and it is illegal to remove such items or to harass any wildlife. Commonly seen animals include coyote, bobcat,
black-tailed deer Two forms of black-tailed deer or blacktail deer that occupy coastal woodlands in the Pacific Northwest of North America are subspecies of the mule deer (''Odocoileus hemionus''). They have sometimes been treated as a species, but virtually all r ...
, California ground squirrels,
fox squirrel The fox squirrel (''Sciurus niger''), also known as the eastern fox squirrel or Bryant's fox squirrel, is the largest species of tree squirrel native to North America. Despite the differences in size and coloration, it is sometimes mistaken for A ...
s and grey foxes; many other mammals including
mountain lion The cougar (''Puma concolor'') is a large cat native to the Americas. Its range spans from the Canadian Yukon to the southern Andes in South America and is the most widespread of any large wild terrestrial mammal in the Western Hemisphere. ...
s are present. It is a chief remaining refuge for the threatened Alameda whipsnake,
California red-legged frog The California red-legged frog (''Rana draytonii'') is a species of frog found in California (USA) and northern Baja California (Mexico). It was formerly considered a subspecies of the northern red-legged frog (''Rana aurora''). The frog is an IU ...
. Less common wildlife species include the reintroduced peregrine falcon, ringtail cats, and to the east American badgers,
San Joaquin kit fox The endangered San Joaquin kit fox (''Vulpes macrotis mutica'') was formerly very common in the San Joaquin Valley and through much of Central California. Its 1990 population was estimated to be 7,000. This subspecies is still endangered, after n ...
, roadrunners,
California tiger salamander The California tiger salamander (''Ambystoma californiense'') is a vulnerable amphibian native to California. It is a mole salamander. Previously considered to be a subspecies of the tiger salamander (''A. tigrinum)'', the California tiger sal ...
, and
burrowing owl The burrowing owl (''Athene cunicularia''), also called the shoco, is a small, long-legged owl found throughout open landscapes of North and South America. Burrowing owls can be found in grasslands, rangelands, agricultural areas, deserts, or an ...
s. There are also exotic (non-native) animals such as the red fox and opossum, the latter being North America's only marsupial. In September and October male tarantula spiders can be seen (''
Aphonopelma iodius ''Aphonopelma iodius'' is a species of spider in the tarantula family Theraphosidae, found in United States (California, Nevada, Arizona and Utah). A 1997 paper combined it with three other previously described species (''A. angusi'', ''A.&n ...
'') as they seek a mate. These spiders are harmless unless severely provoked, and their bite is only as bad as a bee sting. More dangerous are black widow spiders, far less likely to be encountered in the open. In the wintertime, between November and February, bald eagles and golden eagles are present. These birds are less easily seen than many raptors; golden eagles, particularly, fly at high elevations. Mount Diablo is part of the Altamont Area/Diablo Range, which enjoys the largest concentration of golden eagles anywhere. In recent years there have been credible sightings of California condors, which have been reintroduced at Pinnacles National Park, located to the south in the Gilroy-Hollister area. Of special note as potential hazards are Northern Pacific rattlesnake. While generally shy and non-threatening, one should be observant and cautious of where one steps to avoid accidentally disturbing one. They are often found warming themselves in the open (as on trails and ledges) on cool, sunny days. Other wildlife to avoid include fleas, ticks and mosquitoes. There has also been an increase in the mountain lion population in the larger region and one should know how to respond if these animals are encountered. Please see the ''mountain lion safety tips'' in the
mountain lion The cougar (''Puma concolor'') is a large cat native to the Americas. Its range spans from the Canadian Yukon to the southern Andes in South America and is the most widespread of any large wild terrestrial mammal in the Western Hemisphere. ...
article. File:Elanus leucurus 3.jpg, White-tailed kite File:AWonder Pacific Chorus Frog 001.jpg, Pacific tree frog File:Diadophis punctatus 3.jpg, Ring-necked snake File:Aspidoscelis tigris munda.jpg, Western whiptail lizard


Facilities

Entrance stations are located at the end of Northgate Road (in
Walnut Creek A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, ''Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true bo ...
) and Diablo Road (in Danville). The Danville entrance is also known as Southgate. If the entrance stations are not operating, park fees may be paid at the junction ranger station, where the two roads join. From here the road reaches the summit of the mountain, where there is a visitors center housing an observation deck and natural history exhibits. From the elevation of the lower lot the Mary Bowerman Trail is a level wheelchair-accessible path and boardwalk with interpretive stations that extends part way around the mountain; a regular single track trail completes the loop. There are of hiking and equestrian trails, some available for mountain biking. Camping facilities are available within the park. There are numerous picnic sites. Pets are restricted and require proper documentation for rabies (not just a tag). Daytime visitors must exit the park by sunset except for special events. Some picnic spots may be reserved but most are available without reservation. Alcohol is strictly forbidden in the park. Fires are allowed only during the wet season (generally December through April), and only in sanctioned fire pits. The park may be closed on windy days during the dry season due to extremely hazardous fire conditions. Two additional entrances with parking for hikers are provided on the northwest side of the park at Mitchell Canyon and Donner Canyon. Mitchell Canyon provides easy access to Black Point and Eagle Peak. Donner Canyon provides hikers access to Eagle Peak, Mount Olympia, North Peak, and the popular Falls Trail, which features several seasonal waterfalls.


Climate

The National Weather Service maintains a weather station at Mount Diablo Junction, 2,170 feet (661 m) above sea level. The warmest month at the station is July with an average high of 85.2 °F (29.5 °C) and an average low of 59.6 °F (15.3 °C). The coolest month is January with an average high of 55.6 °F (13.1 °C) and an average low of 39.3° (4.1 °C). The highest temperature recorded there was 111 °F (43.9 °C) on July 15, 1972. The lowest temperature on record was 14 °F (-10 °C) on February 6, 1989, and on December 14, 1990. (The '' San Francisco Chronicle'' reported that the temperature dropped to 10 °F (-12.2 °C) at the summit on January 21, 1962.) Temperatures reach 90 °F (32.2 °C) or higher on an average of 36.0 days each year and 100 °F (37.8 °C) or higher on 3.3 days each year. Lows of 32 °F (0 °C) or lower occur on an average of 15.4 days annually. Annual precipitation averages . The most precipitation recorded in a month was in February 1998. The greatest 24-hour precipitation was on January 21, 1972. The average annual days with measurable precipitation is 65.3 days. Snowfall at Mount Diablo Junction averages each year. Prior to 2009, the most snowfall observed in a month was in April 1975; that same month saw in one day (April 4, 1975). The greatest snow depth was on January 27, 1972. Measurable snowfall does not occur every year, so the annual average days with measurable snowfall is only .5 days. Snow is more common in the upper reaches of the mountain. On December 7, 2009 Mount Diablo received a rare snow event of , receiving more in one day than what it normally receives in one year.


Data-collecting note

The Mt. Diablo Junction weather station is positioned at only about 55 percent of the mountain's height. Temperatures and snow levels are notably different than at the upper reaches of the mountain, where lower temperatures and greater snowfall may have occurred, but simply have not been recorded. Nearby Bay Area mountains, like Mount Hamilton, have their weather stations at or near the summit. This is why recorded snow levels on Mount Hamilton are much higher than the ones recorded at Mount Diablo Junction, even though the difference in height of Mount Hamilton and Mount Diablo is only about . Three conditions are measured at the actual summit, however: wind speed, wind direction and temperature; and are available by an automatic telephone voice response system. Recorded information concerning gate open times, road and pet restrictions, and events is available at another number. These numbers are posted at the park website.


Art and literature

Mount Diablo has inspired many artists and writers. Early work centered on exploration, surveying and was related to the rise and popularization of tourism in the Pacific west. Themes were suggested and heightened by early tourism promoters, the beginnings of the area's preservation and the rise of the environmental movement. The focus was accelerated by artists associated with the
University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...
, the California College of Arts, the actions of the organizations Save Mount Diablo and the Mount Diablo Interpretive Association, and area art centers, galleries, and museums. In modern times Mount Diablo art has been most strongly represented in plein aire painting, especially the group Artists for Action, and photography. Representative work includes books and articles by classical writers such as William Brewer, Richard Henry Dana, Jr., Alexandre Dumas, père, Bret Harte, and the Reverend Thomas Starr King, and modern ones such as Mark Allen Cunningham. Poets whose work features the mountain include
Philip Lamantia Philip Lamantia (October 23, 1927 – March 7, 2005) was an American poet and lecturer. His poems were often visionary, ecstatic, terror-filled, and erotic, exploring the subconscious world of dreams and linking it to daily experiences, while s ...
, Andrew Schelling, and Helen Pinkerton. Early painters include Thomas Almond Ayres, Eugene Camerer, W. H. Dougal, Eduard Hildebrandt, Charles Hittell, Edward Jump, William Keith, John Ross Key, Charles Koppel, Edward Lehman, Pascal Loomis, Henry Miller, Joseph Warren Revere, through Clarkson Dye and others, to modern painters such as Robert Becker, Frank J. Bette, Ruth Breve, Betty Boggess Lathrap, Paul Carey, Bob Chapla, Mary Lou Correia, Ellen Curtis, Pam Della, Susan Dennis, Warren Dreher, John Finger, Pam Glover, JoAnn Hanna, Peg Humphreys, Don Irwin, Jeanne Kapp, Geri Keary, Chris Kent, Paul Kratter, Eunice Kritscher, Fred Martin, Cathy Moloney, Shirley Nootbaar, Charlotte Panton, Greg Piatt, Kenneth Potter, Robin Purcell, Ocean Quigley, Don Reich, Mary Silverwood, Barbara Stanton, Bruce Stangeland, Marty Stanley, and even the recognized comic book painter Dan Brereton. Photographers include Ansel Adams, Cleet Carlton, Alfred A. Hart, Scott Hein, Stephen Joseph, Don Paulson, Brad Perks, Robert Picker, Richard Rollins, David Sanger, Michael Sewell and Bob Walker. The mountain has inspired musical artists ranging from the
Kronos Quartet The Kronos Quartet is an American string quartet based in San Francisco. It has been in existence with a rotating membership of musicians for almost 50 years. The quartet covers a very broad range of musical genres, including contemporary classic ...
to commissioned works by the
California Symphony The California Symphony is a professional orchestra based in Walnut Creek, California, in the East Bay region of the San Francisco Bay Area. The orchestra, which "may be the most forward-looking music organization around", performs in the Lesher Cen ...
. The pop-punk band
The Story So Far The Story So Far may refer to: __NOTOC__ Books * ''The Story of Sar'' (book), a 2003 book by Bhawana Somaaya Films * ''The Story So Far'' (2001 film), a film about the band Sick of It All * ''The Story So Far'' (2002 film), a documentary about ...
, who are from the area, have a song titled Mt. Diablo. The mountain's name is the source for the "Devils" part of the name of the
Blue Devils Drum and Bugle Corps The Blue Devils Drum and Bugle Corps is a World Class competitive junior drum and bugle corps based in Concord, California. The Blue Devils are members of Drum Corps International (DCI). They have finished first or second since 2007, and have ...
, a 17 time Drum Corps International world champion corps, founded and based in Concord, California since 1957.
David Brevik David Brevik (born February 14, 1968) is an American video game designer, producer and programmer who served as the co-founder and president of Blizzard North. He is best known for the critically acclaimed ''Diablo'' franchise. Currently he s ...
, head of
Blizzard North Blizzard North (formerly known as Condor) was an American video game development studio based in San Mateo, California. The studio was the Bay Area division of Blizzard Entertainment, known for its ''Diablo'' series. The company was originally ba ...
, got the idea for the name of the Diablo game franchise from Mt. Diablo while living nearby."To Hell and Back Again:How the Game Industry Has Changed Since Diablo," talk given by David Brevik at Penny Arcade Expo East on March 12, 2011. In Marvel Comics, the Black Celestial named Tiamut was imprisoned under Mt Diablo for his crimes against the other Celestials. Arishem and the others sealed him away beneath the Diablo Mountain Range in California. See Fantastic Four Vol 1 #339 and #340.


Events

Each Fall the male tarantulas of Mt. Diablo emerge from their burrows to seek mates. The Mt. Diablo Interpretive Association offers guided hikes to observe the migration. The "March of the Tarantulas" can begin as early as August and last through October. Every year since 1964, the Pearl Harbor survivors and their families have memorialized Pearl Harbor Day by relighting the historic Beacon atop Mount Diablo's summit. A ceremony memorializing the
attack on Pearl Harbor The attack on Pearl HarborAlso known as the Battle of Pearl Harbor was a surprise military strike by the Imperial Japanese Navy Air Service upon the United States against the naval base at Pearl Harbor in Honolulu, Territory of Hawaii ...
on December 7, 1941 is held at the Cal State East Bay Concord Campus, with some of the few remaining survivors who are present. (In 2020, the ceremony was virtual.) This ceremony is made possible due to the support of Mount Diablo State Park, California State University - East Bay: Concord Campus, Save Mount Diablo, CCTV, Vietnam Helicopters Museum, and the Sons and Daughters of Pearl Harbor Survivors. Under cloudless conditions, more interesting than the sunset itself is the view of the progression of the mountain's shadow across the California Central Valley from the south to the distant Sierra Nevada to the north, finally appearing for a few moments above the horizon as a shadow in the post-sunset sky glow. In April 1946, an Army C-45 transport plane crashed on the north side of the mountain, killing the pilot and co-pilot. ''Save Mount Diablo'' sponsors many spring and fall schedules of events on the mountain, Spring on Diablo and Autumn on Diablo, as well as many other special events, including its anniversary event, Moonlight on the Mountain; Four Days Diablo, a trip on the Diablo Trail; the Mount Diablo Challenge, an annual hill climb to the summit with more than 1,100 cyclists each October; and the Mount Diablo Trail Adventure, combined 10k and half-marathon hikes and runs. The park is popular in winter, when Bay Area residents can enjoy the rare experience of snowfall on the mountain. Snow occurs from the lower reaches of the park all the way to the peak, as was the case in February 2001 and February and March 2006. On Friday, March 10, 2006, an extremely cold storm moved into the region from the
Gulf of Alaska The Gulf of Alaska (Tlingit: ''Yéil T'ooch’'') is an arm of the Pacific Ocean defined by the curve of the southern coast of Alaska, stretching from the Alaska Peninsula and Kodiak Island in the west to the Alexander Archipelago in the east ...
, and noticeable amounts of snow fell in all regions of the Bay Area above 500 feet (152 m). The summit of the mountain received around six inches (15 cm) of snow at its peak, and the access roads were closed to automobiles at the 3,000 feet (914 m) mark due to the hazardous icy conditions above. Occasionally there will be public access to astronomical observations made by a local astronomy club. This club was allocated a small parcel on the mountain and developed a permanent observatory at this location. The observatory has a computer-controlled telescope with a CCD camera.


Mount Diablo Challenge bicycle race

The Mount Diablo Challenge is a bicycle race held annually on the first Sunday in October and benefiting non-profit, Save Mount Diablo's land preservation programs. The race begins at the Athenian School at the base of the mountain and climbs in . The race typically draws between 800 and 1,100 riders each year who compete in a mass-start format. Bicycle riders of every age and ability are represented in the field, from weekend enthusiasts to top professionals. Prizes are typically awarded to the top overall male and female finishers, along with several age-specific categories. The most coveted prize is the special "One-Hour" T-shirts, awarded to those who finish the climb in less than one hour.


Course record

The course record for the Mount Diablo climb currently stands at 43 minutes, 33 seconds, set on October 5, 2008, by Nate English (ZteaM) 4 days after breaking his thumb in a bike accident. He broke the 44 minutes, 58 seconds record, set in 2004 by former professional cyclist Greg Drake (Webcor Cycling Team) of Redwood City, California. The previous course record was set by former professional cyclist Mike Engleman (Coors Light Pro Cycling Team) in 1990 with a time of 45 minutes, 20 seconds. The fastest woman's time recorded at the Mount Diablo climb was set in 2012 by Flavia Oliveira (48 minutes, 13 seconds). In 2016, Flavia competed at the Olympic Games in Rio de Janeiro where she finished in seventh place. Outside of the actual Mt Diablo Challenge each October, the climb is one of the more popular uploaded to
Strava Strava is an American internet service for tracking physical exercise which incorporates social network features. It is mostly used for cycling and running using Global Positioning System data. Strava uses a freemium model with some features on ...
, with over 11000 attempts recorded as of mid 2014. The top 10 times listed there are all from the
Tour of California The Tour of California (officially sponsored as the Amgen Tour of California) was an annual professional road cycling stage race on the UCI World Tour and USA Cycling Professional Tour that ran from 2006 to 2019. It was the only event on the ...
, which has used Mt Diablo as a stage several times. The fastest time (40:49) as of January 2021 is held by professional cyclist Lawson Craddock set in May 2013.


In popular culture

In '' Grand Theft Auto: San Andreas'' a mountain range known as ''Mount Chiliad'' was based on Mount Diablo. It reappears in Grand Theft Auto V. The silhouette of the mountain was used for the cover art of PIHKAL and TIHKAL by '' Alexander Shulgin''. In the book '' The Lost Hero'' by ''
Rick Riordan Richard Russell Riordan Junior (; born June 5, 1964) is an American author, best known for writing the ''Percy Jackson & the Olympians'' series. Riordan's books have been translated into forty-two languages and sold more than thirty million co ...
'', Piper McLean's father is captured and help captive on the summit of Mount Diablo by the giant ''
Enceladus Enceladus is the sixth-largest moon of Saturn (19th largest in the Solar System). It is about in diameter, about a tenth of that of Saturn's largest moon, Titan. Enceladus is mostly covered by fresh, clean ice, making it one of the most refle ...
''.
Diablo (video game) ''Diablo'' is an action role-playing video game developed by Blizzard North and released by Blizzard Entertainment in January 1997, and is the first installment in the video game series of the same name. Set in the fictional Kingdom of Khand ...
was named after this mountain by
David Brevik David Brevik (born February 14, 1968) is an American video game designer, producer and programmer who served as the co-founder and president of Blizzard North. He is best known for the critically acclaimed ''Diablo'' franchise. Currently he s ...
. The pop-punk band
The Story So Far The Story So Far may refer to: __NOTOC__ Books * ''The Story of Sar'' (book), a 2003 book by Bhawana Somaaya Films * ''The Story So Far'' (2001 film), a film about the band Sick of It All * ''The Story So Far'' (2002 film), a documentary about ...
have a song named after the mountain on their debut record.


Famous residents

James "Grizzly" Adams was a frequent visitor and resident on Mount Diablo in the mid-1850s. Robert Walter "Bob" Jones, the first professional baseball player from Contra Costa County, was born in the "Jones House" in Irish Canyon in 1889, a current acquisition project of Save Mount Diablo. The Mount Diablo Ranch, or Diablo Ranch, was successively owned by Robert Noble Burgess (b. 1878 - d. 1965), who founded the community of Diablo and built the mountain's first auto roads, and millionaire Walter Paul Frick (aka W. P. Frick, b. 1875 - d. 1937), who lived in Diablo and was important in the creation of the State Park in 1931, including sale of six of the first seven parcels for the new park. Jazz pianist Dave Brubeck grew up on Brubeck Ranch near the park's North Gate entrance. The area for the Blackhawk Farm, including the mountain's southern Black Hills, was acquired from Burgess and created by Ansel Mills Easton, the namesake uncle of photographer Ansel Adams. Eventually nearly two-thirds of the farm was added to Mount Diablo State Park. The remainder was developed as the community of
Blackhawk Black Hawk and Blackhawk may refer to: Animals * Black Hawk (horse), a Morgan horse that lived from 1833 to 1856 * Common black hawk, ''Buteogallus anthracinus'' * Cuban black hawk, ''Buteogallus gundlachii'' * Great black hawk, ''Buteogallus uru ...
by resident developer
Ken Behring Kenneth Eugene Behring (June 13, 1928 – June 25, 2019) was an American real estate developer, and former owner of the National Football League's Seattle Seahawks. Early years Born in Freeport, Illinois, Behring was the son of Mae (Priewe) and El ...
and his partner Ken Hofmann.


Legends and folklore

Mount Diablo has long been the site of numerous reports pertaining to cryptozoology,
hauntings The list of reportedly haunted locations throughout the world, that are locations said to be haunted by ghosts or other supernatural beings, including demons. Reports of haunted locations are part of ghostlore, which is a form of folklore. Ar ...
, mysterious lights, and various other Fortean phenomena (it is rumored that the name "''Mount Diablo''" is derived from the propensity for such weird events to be alleged at, or in the immediate vicinity of, the mountain). Phantom black "
panthers Panther may refer to: Large cats *Pantherinae, the cat subfamily that contains the genera ''Panthera'' and ''Neofelis'' **''Panthera'', the cat genus that contains tigers, lions, jaguars and leopards. ***Jaguar (''Panthera onca''), found in Sout ...
" are seen with unusual frequency on the slopes of the mountain, as well as at the "''Devil's Hole''" region of the Las Trampas Regional Wilderness. As early as 1806, General
Mariano Guadalupe Vallejo Don (honorific), Don Mariano Guadalupe Vallejo (4 July 1807 – 18 January 1890) was a Californios, Californio general, statesman, and public figure. He was born a subject of Spain, performed his military duties as an officer of the Republic of ...
(July 4, 1807 – January 18, 1890) reported an encounter with a flying, spectral apparition, while engaged in military operations against the ''Bolgones'' band of the Bay Miwok tribe. In 1873, a live frog was said to be found within a slab of limestone at a mine on Mount Diablo.


See also

* Diablo Range * Diablo, California *
List of highest points in California by county This is a list of highest points in California, in alphabetical order by county. All elevations use the North American Vertical Datum of 1988 (NAVD88), the currently accepted vertical control datum for United States, Canada and Mexico. Elevations ...
* List of summits of the San Francisco Bay Area


Notes


References

*


External links

* * *
Mount Diablo
an

Panoramic views from the summit of Mount Diablo. Mediacom. {{DEFAULTSORT:Diablo, Mount Diablo Range Mountains of Contra Costa County, California State parks of California Parks in Contra Costa County, California National Natural Landmarks in California Native American mythology of California Religious places of the indigenous peoples of North America California Historical Landmarks Civilian Conservation Corps in California Climbs in cycle racing in the United States Gliding in the United States Hang gliding sites Protected areas established in 1931 1931 establishments in California Landmarks in the San Francisco Bay Area Mountains of Northern California Mountains of the San Francisco Bay Area Parks in the San Francisco Bay Area Locations in Native American mythology