Mount Diablo
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Mount Diablo is a mountain of the
Diablo Range The Diablo Range is a mountain range in the California Coast Ranges subdivision of the Pacific Coast Ranges in northern California, United States. It stretches from the eastern San Francisco Bay Area at its northern end to the Salinas Valley a ...
, in
Contra Costa County Contra Costa County (; ''Contra Costa'', Spanish language, Spanish for 'Opposite Coast') is a U.S. county, county located in the U.S. state of California, in the East Bay of the San Francisco Bay Area. As of the 2020 United States census, the ...
of the eastern
San Francisco Bay Area The San Francisco Bay Area, commonly known as the Bay Area, is a List of regions of California, region of California surrounding and including San Francisco Bay, and anchored by the cities of Oakland, San Francisco, and San Jose, California, S ...
in
Northern California Northern California (commonly shortened to NorCal) is a geocultural region that comprises the northern portion of the U.S. state of California, spanning the northernmost 48 of the state's List of counties in California, 58 counties. Northern Ca ...
. 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 California State Parks is the state park system for the U.S. state of California. The system is administered by the California Department of Parks and Recreation, a department under the California Natural Resources Agency. The California State ...
.


Geography

The summit is accessible by foot, bicycle, or motor vehicle. Road access is via North Gate Road or South Gate Road.


Mount Diablo State Park

The peak is in Mount Diablo State Park, a
state park State parks are parks or other protected areas managed at the sub-national level within those nations which use "Federated state, state" as a political subdivision. State parks are typically established by a state to preserve a location on accou ...
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
watershed Watershed may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, an area of land where surface water converges (North American usage) Music * Watershed Music Festival, an annual country ...
s, which are buffered in some areas with private lands that have been protected by conservation
easement An easement is a Nonpossessory interest in land, nonpossessory right to use or enter onto the real property of another without possessing it. It is "best typified in the right of way which one landowner, A, may enjoy over the land of another, B" ...
s.


Viewshed

On a clear day, the
Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...
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 in Lassen Volcanic National Park in Northern California. Located in the Shasta Cascade region above the northern Sacramento Valley, it is the southernmost active vo ...
, 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. The view from the top offers a 360 degree view of Yosemite Val ...
in
Yosemite National Park Yosemite National Park ( ) is a List of national parks of the United States, national park of the United States in California. It is bordered on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The p ...
is visible, but
Half Dome Half Dome is a quartz monzonite batholith at the eastern end of Yosemite Valley in Yosemite National Park, California. It is a well-known rock formation in the park, named for its distinct shape. One side is a sheer face while the other three s ...
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 A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a ''gulf'', ''sea'', ''sound'', or ''bight''. A ''cove'' is a small, ci ...
,
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 ...
, San Rafael, Carquinez,
Benicia Benicia ( , ) is a city in Solano County, California, located on the north bank of the Carquinez Strait in the North Bay region of the San Francisco Bay Area. It served as the capital of California for nearly thirteen months from 1853 to 1854. ...
,
Antioch Antioch on the Orontes (; , ) "Antioch on Daphne"; or "Antioch the Great"; ; ; ; ; ; ; . was a Hellenistic Greek city founded by Seleucus I Nicator in 300 BC. One of the most important Greek cities of the Hellenistic period, it served as ...
, and Rio Vista. Many 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 The San Francisco Bay Area, commonly known as the Bay Area, is a region of California surrounding and including San Francisco Bay, and anchored by the cities of Oakland, San Francisco, and San Jose. The Association of Bay Area Governments ...
,
delta Delta commonly refers to: * Delta (letter) (Δ or δ), the fourth letter of the Greek alphabet * D (NATO phonetic alphabet: "Delta"), the fourth letter in the Latin alphabet * River delta, at a river mouth * Delta Air Lines, a major US carrier ...
, and Central Valley, and good visibility even from the
Mother Lode Mother lode is a principal vein or zone of gold or silver ore. The term is also used colloquially to refer to the real or imaginary origin of something valuable or in great abundance. Term The term probably came from a literal translation of ...
, all key regions during the
gold rush A gold rush or gold fever is a discovery of gold—sometimes accompanied by other precious metals and rare-earth minerals—that brings an onrush of miners seeking their fortune. Major gold rushes took place in the 19th century in Australia, ...
and early
statehood A state is a political entity that regulates society and the population within a definite territory. Government is considered to form the fundamental apparatus of contemporary states. A country often has a single state, with various administrat ...
, 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. It boasts one of the largest viewsheds in the Western United States and played a key role in California history.


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 col ...
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 Mount Tamalpais (; ; Miwok languages, Miwok: ''Támal Pájiṣ''), known locally as Mount Tam, is a mountain, peak in Marin County, California, Marin County, California, United States, often considered symbolic of Marin County. Much of Mount Tama ...
) 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 at time of European contact. Their members spoke dialects of three distinct languages:
Ohlone The Ohlone ( ), formerly known as Costanoans (from Spanish meaning 'coast dweller'), are a Native Americans in the United States, Native American people of the Northern California coast. When Spanish explorers and missionaries arrived in the l ...
,
Bay Miwok The Bay Miwok are a cultural and linguistic group of Miwok, a Native Americans in the United States, Native American people in Northern California who live in Contra Costa County, California, Contra Costa County. They joined the Franciscan missi ...
, and
Northern Valley Yokuts Northern Valley Yokuts is a dialect network within the Valley Yokuts division of the Yokutsan languages spoken in the Central Valley (California), Central Valley of California. Among the languages belonging to the network are Chawchila Yokuts, Ch ...
. The
Chochenyo The Chochenyo (also called Chocheño, Chocenyo) are one of the divisions of the Indigenous Ohlone (Costanoan) people of Northern California. The Chochenyo reside on the east side of the San Francisco Bay (the East Bay), primarily in what is no ...
-speaking Ohlone from Mission San Jose and the East Bay area, call the mountain , meaning "at the dawn of time". Further inland, the
Nisenan The Nisenan are a group of Native Americans in the United States, Native Americans and an Indigenous people of California from the Yuba River and American River watersheds in Northern California and the California Central Valley. According to a ...
of the Sacramento Valley call 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 is , and a Northern Sierra Miwok name is . 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 The Bay Miwok are a cultural and linguistic group of Miwok, a Native Americans in the United States, Native American people in Northern California who live in Contra Costa County, California, Contra Costa County. They joined the Franciscan missi ...
–speaking tribe. As early as 1811, Spanish colonists referred to the mountain as ("High Hill of the Volvon") or sometimes .


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 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). 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 Thomas Starr King (December 17, 1824 – March 4, 1864), often known as Starr King, was an American Universalist and Unitarian minister, influential in California politics during the American Civil War, and Freemason. Starr King spoke ze ...
, a Unitarian clergyman, abolitionist, Republican, Yosemite advocate, cultural Unionist, and California's leading intellectual. Today it is known 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 Yahweh was an Ancient Semitic religion, ancient Semitic deity of Weather god, weather and List of war deities, war in the History of the ancient Levant, ancient Levant, the national god of the kingdoms of Kingdom of Judah, Judah and Kingdom ...
. Suggestions by other individuals included Mount
Miwok The Miwok (also spelled Miwuk, Mi-Wuk, or Me-Wuk) are members of four linguistically related Native Americans in the United States, Native American groups indigenous to what is now Northern California, who traditionally spoke one of the Miwok lan ...
and Mount
Ohlone The Ohlone ( ), formerly known as Costanoans (from Spanish meaning 'coast dweller'), are a Native Americans in the United States, Native American people of the Northern California coast. When Spanish explorers and missionaries arrived in the l ...
, after local Indian tribes. Finally Mijares proposed Mount
Reagan Ronald Wilson Reagan (February 6, 1911 – June 5, 2004) was an American politician and actor who served as the 40th president of the United States from 1981 to 1989. He was a member of the Republican Party and became an important figure in ...
, 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, metes-and-bounds of a country.Jo Henssen, ''Basic Principles of the Main Cadastral Systems in the World,'/ref> Often it is represente ...
surveys of a large area. Subsequent surveys in much of
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
,
Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...
and
Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...
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 for which a fee (or ''Toll (fee), toll'') is assessed for passage. It is a form of road pricing typically implemented to help recoup the costs of road construction and ...
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 language, Spanish for "little") is the most populous city in Butte County, California, United States. Located in the Sacramento Valley region of Northern California, the city had a population of 101,475 in the 2020 United Sta ...
, 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 Navigation is a field of study that focuses on the process of monitoring and controlling the motion, movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navig ...
beacon, the Standard Diablo tower, was erected by
Standard Oil Standard Oil Company was a Trust (business), corporate trust in the petroleum industry that existed from 1882 to 1911. The origins of the trust lay in the operations of the Standard Oil of Ohio, Standard Oil Company (Ohio), which had been founde ...
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 The Civilian Conservation Corps (CCC) was a voluntary government unemployment, work relief program that ran from 1933 to 1942 in the United States for unemployed, unmarried men ages 18–25 and eventually expanded to ages 17–28. The CCC was ...
, 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 university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...
. 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 KOVR (channel 13) is a television station licensed to Stockton, California, United States, serving as the CBS outlet for the Sacramento area. It is owned and operated by the network's CBS News and Stations division alongside KMAX-TV (channel ...
(channel 13). The Mount Diablo site gave KOVR, which was based in Stockton, regional coverage that also included San Francisco and
Sacramento Sacramento ( or ; ; ) is the capital city of the U.S. state of California and the seat of Sacramento County. Located at the confluence of the Sacramento and American Rivers in Northern California's Sacramento Valley, Sacramento's 2020 p ...
. 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: Places Australia * Jackson, Queensland, a town in the Maranoa Region * Jackson North, Queensland, a locality in the Maranoa Region * Jackson South, Queensland, a locality in the Maranoa Region * Jackson oil field in Durham, ...
in order to become an
ABC ABC are the first three letters of the Latin script. ABC or abc may also refer to: Arts, entertainment and media Broadcasting * Aliw Broadcasting Corporation, Philippine broadcast company * American Broadcasting Company, a commercial American ...
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 The East Bay Regional Park District (EBRPD) is a Special-purpose district, special district operating in Alameda County, California, Alameda County and Contra Costa County, California, within the East Bay (California), East Bay area of the San Fra ...
, including Morgan Territory Regional Preserve,
Brushy Peak Regional Preserve Brushy Peak Regional Preserve is a regional park that is part of the East Bay Regional Park District, East Bay Regional Parks (EBRPD) and the Livermore Area Recreation and Park District (LARPD) systems. It is located in unincorporated land in Alame ...
,
Vasco Caves Regional Preserve Vasco Caves Regional Preserve is a natural and cultural protected area located on the eastern slope of Mount Diablo, on Vasco Road within eastern Contra Costa County, California. It was created to preserve wildlife habitats, California chaparral ...
, and
Round Valley Regional Preserve Round Valley Regional Preserve is a regional park just outside Antioch, CA and Brentwood, CA that is part of the East Bay Regional Parks (EBRPD) system. It is on Marsh Creek Road, approximately west of the intersection with Vasco Road. The pa ...
. 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 de ...
(now in the process of being converted to non military use), Indian Valley, Shell Ridge Open Space and Lime Ridge Open Spaces near the 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 wat ...
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 pre ...
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 * Common black hawk, ''Buteogallus anthracinus'' * Cuban black hawk, ''Buteogallus gundlachii'' * Great black hawk, ''Buteogallus urubitinga'' * Mangrove black hawk, ''Buteogallus (anthracinus) s ...
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 Marsh Creek 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.


Natural history


Geology

There are three major groups of rocks composing Mount Diablo -- the Mount Diablo Ophiolite group, dating to the Jurassic; the Franciscan Complex, dating to the Jurassic and Cretaceous; and the combination of the Great Valley Group (Jurassic and Cretaceous) and Younger Sedimentary rocks (Cenozoic). Ophiolite is a kind of rock that forms in mid-ocean ridges. The Coast Range Ophiolite is ancient oceanic crust caught between an ancient
subduction zone Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...
off California near the end of the Jurassic, and a former shoreline in the ancient Sierra foothills. This is the source of the ophiolite of Mount Diablo, called the Mount Diablo Ophiolite, which underlies it north of a line drawn from Long Ridge through Murchio Gap. Basalt, diabase, and serpentinite can be found. The Franciscan Complex underlies the central area of Mount Diablo's summit and the North Peak. It is an "accretionary complex", formed in an east-dipping subduction zone off California as part of the upper oceanic crust (pillow basalt) and what it carried (chert, graywacke, shale, small islands, sea mounts) were scraped off during the process of subduction. These elements were then mixed and partially subducted before ending up on and under the adjacent continental crust. Accretionary faulting forced the complex under the Coast Range Ophiolite (including the Mount Diablo Ophiolite), and their contact is a
fault plane In geology, 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 f ...
, known as the Coast Range Fault. The Franciscan Complex likely underwent metamorphism there, around 12 miles deep. Today, on land, the Franciscan Complex is made up of numerous large and small blocks of various types of rock in a sheared matrix. Between the late Cretaceous and early Eocene, extensional faulting, and ductile thinning of serpentinite in the ophiolite, reduced the weight on the complex, causing it to rise to a depth of ~2 miles. The Great Valley Group is composed of sedimentary rocks deposited underwater between the Upper Jurassic and the Cretaceous between the ancient Sierra Nevada and the western subduction zone, over the ophiolite basement of the Central Valley. The Mount Diablo area, a persistent "high" though not yet a mountain, was intermittently submerged well into the Pliocene. This region surrounding Mount Diablo was uplifted during the
Tertiary Period The Tertiary ( ) is an obsolete Period (geology), geologic period spanning 66 million to 2.6 or 1.8 million years ago. The period began with the extinction of the non-bird, avian dinosaurs in the Cretaceous–Paleogene extinction event, at t ...
. The Younger Sedimentary rocks are described in the following source but are not summarized here. Although the rocks are quite old, Mount Diablo itself is relatively young. The formation of the mountain began about 2 million years ago during the Pliocene. Between the Pliocene and the present, the Franciscan Complex and overlying Great Valley rocks were folded upward by compression caused by a blind
thrust fault A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. I ...
under the mountain. The fold is asymmetrical, and is moving southwest due to the blind thrust fault. After the fold was created, erosion removed overlying Great Valley rocks and exposed the Franciscan Complex in the center of the fold, resulting in the modern Mount Diablo. The mountain is still growing today, as it is squeezed between the active Greenville Fault and Concord Fault, through large periodic earthquakes along the Mount Diablo Thrust Fault. Historically this fault has not been seen to move, but a 1% chance is predicted that it will produce a large earthquake within 30 years. Mount Diablo's "wind caves" were created by water seeping through fractures in and dissolving the Domegine Sandstone. Deposits of glassmaking-grade sand and lower-quality
coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...
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 pre ...
. Guided tours of the sand mines and coal field are provided.


Vegetation

The park's vegetation is mixed
oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...
woodland and savannah and open grassland with extensive areas of
chaparral Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...
and a number of
endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
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''), Mount Diablo phacelia (''Phacelia phacelioides)'' and Mount Diablo sunflower (''Helianthella castanea''). The park includes substantial thickets, isolated examples, and mixed ground cover of
western poison oak ''Toxicodendron diversilobum'' (syn. ''Rhus diversiloba''), commonly named Pacific poison oak or western poison oak, is a woody vine or shrub in the sumac family, Anacardiaceae. It is widely distributed in western North America, inhabiting co ...
. (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 The knobcone pine, ''Pinus attenuata'' (also called ''Pinus tuberculata''), is a tree that grows in mild climates on poor soils. It ranges from the mountains of southern Oregon to Baja California with the greatest concentration in northern Calif ...
(''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 mark the northern extreme of the range of
Coulter pine Coulter pine (''Pinus coulteri''), or big-cone pine, is a conifer in the genus ''Pinus'' of the family Pinaceae. Coulter pine is an evergreen conifer that lives up to 100 years. Horton, Jerome S. 1949. Trees and shrubs for erosion control of sou ...
(''Pinus coulteri''). This species may be seen along the Coulter Pine Trail near the north (Mitchell Canyon) entrance. In 2005 the
endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...
Mount Diablo buckwheat ''Eriogonum truncatum'', the Mount Diablo buckwheat, is a small pink wildflower, believed to have been extinct since 1936 until its rediscovery in 2005. The species is only known to live on Mount Diablo in Contra Costa County, northern Californ ...
(''Eriogonum truncatum''), thought to be extinct because it had been last seen in 1936 and its habitat had been overrun by introduced grasses, was rediscovered in a remote area of the mountain. File:Pinus sabineana 00057.JPG, This ''
Pinus sabiniana ''Pinus sabiniana'' (sometimes spelled ''P. sabineana'') is a pine endemic to California in the United States. Its vernacular names include towani pine, foothill pine, gray pine, ghost pine, and bull pine. The name digger pine was historically ...
'' (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 ''Pedicularis densiflora'', known commonly as Indian warrior or warrior's-plume lousewort, is a plant in the family Orobanchaceae. Indian warrior is native to California and Oregon in western North America and is found in chaparral, forests, C ...
'' File:ARctostaphylos auriculata at Mt. Diablo - Flickr - theforestprimeval (15).jpg, '' Arctostaphylos auriculata'' File:Juniperus californica Mount Diablo.jpg, ''
Juniperus californica ''Juniperus californica'', the California juniper, is a species of juniper native to southwestern North America. Description ''Juniperus californica'' is a shrub or small tree reaching , but rarely up to tall. The bark is ashy gray, typically t ...
'' File:Western wallflower.jpg, ''
Erysimum capitatum ''Erysimum capitatum'' is a species of Erysimum, wallflower known commonly as the sanddune wallflower, western wallflower, or prairie rocket. This species can be found in regions across North America, from the Great Lakes to the West Coast of th ...
'' File:Valley Oak Mount Diablo.jpg, ''
Quercus lobata ''Quercus lobata'', commonly called the valley oak or roble, is the largest of the California oaks. It is endemic to the state, growing in interior valleys and foothills from Siskiyou to San Diego counties. Deciduous, it requires year-round grou ...
'' 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 The coyote (''Canis latrans''), also known as the American jackal, prairie wolf, or brush wolf, is a species of canis, canine native to North America. It is smaller than its close relative, the Wolf, gray wolf, and slightly smaller than the c ...
,
bobcat The bobcat (''Lynx rufus''), also known as the wildcat, bay lynx, or red lynx, is one of the four extant species within the medium-sized wild cat genus '' Lynx''. Native to North America, it ranges from southern Canada through most of the c ...
,
black-tailed deer Black-tailed deer or blacktail deer occupy coastal regions of western North America. There are two subspecies, the Columbian black-tailed deer (''Odocoileus hemionus columbianus'') which ranges from the Pacific Northwest of the United States and ...
,
California ground squirrel The California ground squirrel (''Otospermophilus beecheyi''), also known as the Beechey ground squirrel, is a common and easily observed ground squirrel of the western United States and the Baja California Peninsula; it is common in Oregon and ...
s,
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. It is sometimes mistaken for the American red squirrel or eastern gray squirr ...
s and
grey fox The gray fox (''Urocyon cinereoargenteus''), or grey fox, is an omnivorous mammal of the family Canidae, widespread throughout North America and Central America. This species and its only congener, the diminutive island fox (''Urocyon littoral ...
es; many other mammals including
mountain lion The cougar (''Puma concolor'') (, ''Help:Pronunciation respelling key, KOO-gər''), also called puma, mountain lion, catamount and panther is a large small cat native to the Americas. It inhabits North America, North, Central America, Cent ...
s are present. It is a chief remaining refuge for the
threatened A threatened species is any species (including animals, plants and fungi) which is vulnerable to extinction in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensatio ...
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 I ...
. Less common wildlife species include the reintroduced
peregrine falcon The peregrine falcon (''Falco peregrinus''), also known simply as the peregrine, is a Cosmopolitan distribution, cosmopolitan bird of prey (raptor) in the family (biology), family Falconidae renowned for its speed. A large, Corvus (genus), cro ...
, ringtail cats, and to the east American badgers,
San Joaquin kit fox The San Joaquin kit fox (''Vulpes macrotis mutica'') is an endangered subspecies of kit fox that was formerly very common in the San Joaquin Valley and much of Central California. As an opportunistic hunter, the San Joaquin kit fox primarily p ...
, 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 sala ...
, and
burrowing owl The burrowing owl (''Athene cunicularia''), also called the shoco, is a small, long-legged, primarily terrestrial—though not flightless—species of owl native to the open landscapes of North and South America. They are typically found in gra ...
s. There are also exotic (non-native) animals such as the
red fox The red fox (''Vulpes vulpes'') is the largest of the true foxes and one of the most widely distributed members of the order Carnivora, being present across the entire Northern Hemisphere including most of North America, Europe and Asia, plus ...
and
opossum Opossums () are members of the marsupial order Didelphimorphia () endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 126 species in 18 genera. Opossums originated in South America and entered North A ...
, the latter being North America's only
marsupial Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a r ...
. In September and October male
tarantula Tarantulas comprise a group of large and often hairy spiders of the family Theraphosidae. , 1,100 species have been identified, with 166 genera. The term "tarantula" is usually used to describe members of the family Theraphosidae, although ...
spiders can be seen ('' Aphonopelma iodius'') 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 eagle The bald eagle (''Haliaeetus leucocephalus'') is a bird of prey found in North America. A sea eagle, it has two known subspecies and forms a species pair with the white-tailed eagle (''Haliaeetus albicilla''), which occupies the same niche ...
s and
golden eagle The golden eagle (''Aquila chrysaetos'') is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known bird of pr ...
s 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. A potential hazard is Northern Pacific rattlesnake. While generally shy and non-threatening, 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 or puma (''Puma concolor'') 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'') (, ''Help:Pronunciation respelling key, KOO-gər''), also called puma, mountain lion, catamount and panther is a large small cat native to the Americas. It inhabits North America, North, Central America, Cent ...
article. Although
tule elk The tule elk (''Cervus canadensis nannodes'') is a subspecies of elk found only in California, ranging from the grasslands and marshlands of the Central Valley to the grassy hills on the coast. The subspecies name derives from the tule (), ...
, an elk subspecies found only in California, were historically native to the Mount Diablo Region, they were hunted to extinction by 1850. Northwards expansion of Diablo Range elk to Mount Diablo has been blocked by Interstate 580. In 2006 a bull elk swam across
Suisun Bay Suisun Bay ( ; Wintun for "where the west wind blows") is a shallow tidal estuary (a northeastern extension of the San Francisco Bay) in Northern California. It lies at the confluence of the Sacramento River and San Joaquin River, forming the e ...
from the Grizzly Island herd to Contra Costa County, and historically large herds crossed the
Carquinez Strait The Carquinez Strait (; Spanish: ''Estrecho de Carquinez'') is a narrow tidal strait located in the Bay Area of Northern California, United States. It is part of the tidal estuary of the Sacramento and the San Joaquin rivers as they drain int ...
. File:Elanus leucurus 3.jpg,
White-tailed kite The white-tailed kite (''Elanus leucurus'') is a small raptor found in western North America and parts of South America. It replaces the related Old World black-winged kite in its native range. Taxonomy The white-tailed kite was described in 18 ...
File:AWonder Pacific Chorus Frog 001.jpg, Pacific tree frog File:Diadophis punctatus 3.jpg,
Ring-necked snake ''Diadophis punctatus'', commonly known as the ring-necked snake or ringneck snake, is a small, harmless species of colubrid snake found throughout much of the United States, as well as south in Central Mexico and as far north as Quebec, Canada. ...
File:Aspidoscelis tigris munda.jpg, Western whiptail lizard


Facilities

Entrance stations are located at the end of Northgate Road (in Walnut Creek) 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 A hike is a long, vigorous walk, usually on trails or footpaths in the countryside. Walking for pleasure developed in Europe during the eighteenth century. Long hikes as part of a religious pilgrimage have existed for a much longer time. "Hi ...
and equestrian trails, some available for
mountain biking Mountain biking (MTB) is a sport of riding bicycles off-road, often over rough terrain, usually using specially designed mountain bikes. Mountain bikes share similarities with other bikes but incorporate features designed to enhance durability ...
.
Camping Camping is a form of outdoor recreation or outdoor education involving overnight stays with a basic temporary shelter such as a tent. Camping can also include a recreational vehicle, sheltered cabins, a permanent tent, a shelter such as a Bivy bag ...
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 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 The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weathe ...
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 The ''San Francisco Chronicle'' is a newspaper serving primarily the San Francisco Bay Area of Northern California. It was founded in 1865 as ''The Daily Dramatic Chronicle'' by teenage brothers Charles de Young and M. H. de Young, Michael H. ...
'' 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 snowfall of , more in one day than what is normally received in a decade.


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 university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...
, 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. Richard Henry Dana Jr. (August 1, 1815 – January 6, 1882) was an American lawyer and politician from Massachusetts, a descendant of a colonial family, who gained renown as the author of the classic American memoir ''Two Years Before the Mast'' a ...
,
Alexandre Dumas, père Alexandre Dumas (born Alexandre Dumas Davy de la Pailleterie, 24 July 1802 – 5 December 1870), also known as Alexandre Dumas , was a French novelist and playwright. His works have been translated into many languages and he is one of the mos ...
,
Bret Harte Bret Harte ( , born Francis Brett Hart, August 25, 1836 – May 5, 1902) was an American short story writer and poet best remembered for short fiction featuring miners, gamblers, and other romantic figures of the California Gold Rush. In a caree ...
, and the Reverend
Thomas Starr King Thomas Starr King (December 17, 1824 – March 4, 1864), often known as Starr King, was an American Universalist and Unitarian minister, influential in California politics during the American Civil War, and Freemason. Starr King spoke ze ...
, 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, writer and lecturer. His poetry incorporated stylistic experimentation and transgressive themes, and has been regarded as surrealist and visionary, contributing to the ...
, 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 John Ross Key (September 19, 1754 – October 11, 1821) was a lawyer, a commissioned officer in the Continental Army, a judge, and the father of writer Francis Scott Key. Early life Key was born in Redland, Maryland, to Francis Key and his ...
, 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 Daniel Alan Brereton (born November 22, San Francisco Bay Area) is an American writer and illustrator who has produced notable work in the comic book field. Biography Early life Dan Brereton attended the California College of the Arts and the Ac ...
. Photographers include
Ansel Adams Ansel Easton Adams (February 20, 1902 – April 22, 1984) was an American landscape photographer and environmentalist known for his Monochrome photography, black-and-white images of the American West. He helped found Group f/64, an association ...
, 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 50 years. The quartet covers a very broad range of musical genres, including contemporary classical musi ...
to commissioned works by the
California Symphony The California Symphony is a professional orchestra based at the Lesher Center for the Arts in Walnut Creek, California, in the East Bay region of the San Francisco Bay Area. It was founded in 1986 and is a member of the Association of California ...
. Local pop-punk band
The Story So Far The Story So Far may refer to: __NOTOC__ Books * ''The Story of Far'' (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 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 in the top three at the DCI World Cham ...
, 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'' series. Currently, he ser ...
, 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 San Francisco Bay Area, Bay Area division of Blizzard Entertainment, and it was known for the Diablo (series ...
, 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 Empire of Japan on the United States Pacific Fleet at Naval Station Pearl Harbor, its naval base at Pearl Harbor on Oahu, Territory of ...
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 The Central Valley is a broad, elongated, flat valley that dominates the interior of California, United States. It is wide and runs approximately from north-northwest to south-southeast, inland from and parallel to the Pacific coast. It cover ...
from the south to the distant
Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...
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 Hillclimbing, also known as hill climbing, speed hillclimbing, or speed hill climbing, is a branch of motorsport in which drivers compete against the clock to complete an uphill course. It is one of the oldest forms of motorsport, since the firs ...
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 ...
, 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 The modern Olympic Games (Olympics; ) are the world's preeminent international Olympic sports, sporting events. They feature summer and winter sports competitions in which thousands of athletes from around the world participate in a Multi-s ...
in
Rio de Janeiro Rio de Janeiro, or simply Rio, is the capital of the Rio de Janeiro (state), state of Rio de Janeiro. It is the List of cities in Brazil by population, second-most-populous city in Brazil (after São Paulo) and the Largest cities in the America ...
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 started out tracking mostly outdoor cycling and running activities using Global Positioning System (GPS) data, but now incorpor ...
, 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 Gregory Lawson Craddock (born February 20, 1992) is an American former road and track racing cyclist, who competed as a professional from 2011 to 2024. He is known for his achievement in finishing the 2018 Tour de France despite being seriously i ...
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 ''Grand Theft Auto V'' is a 2013 action-adventure game developed by Rockstar North and published by Rockstar Games. It is the seventh main entry in the Grand Theft Auto, ''Grand Theft Auto'' series, following 2008's ''Grand Theft Auto IV'', and ...
''. * The silhouette of the mountain was used for the cover art of the books ''
PiHKAL ''PiHKAL: A Chemical Love Story'' is a book by Alexander Shulgin and Ann Shulgin published in 1991. The subject of the work is Psychoactive drug, psychoactive phenethylamine Derivative (chemistry), chemical derivatives, notably those that act ...
'' and ''
TiHKAL ''TiHKAL: The Continuation'' is a 1997 book written by Alexander Shulgin and Ann Shulgin about a family of psychoactive drugs known as tryptamines. A sequel to '' PiHKAL: A Chemical Love Story'', ''TiHKAL'' is an acronym that stands for "Trypt ...
'' by
Alexander Shulgin Alexander Theodore "Sasha" Shulgin (June 17, 1925 – June 2, 2014) was an American biochemist, broad researcher of synthetic psychoactive compounds, and author of works regarding these, who independently explored the organic chemistry and ph ...
. * In the book ''
The Lost Hero ''The Lost Hero'' is an American fantasy-adventure novel written by Rick Riordan, based on Greek and Roman mythology. It was published on October 12, 2010, and is the first book in ''The Heroes of Olympus'' series, a sequel to the ''Percy Jacks ...
'' by
Rick Riordan Richard Russell Riordan Jr. ( ; 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 cop ...
, Piper McLean's father is captured and held captive on the summit of Mount Diablo by the giant Enceladus. * The pop-punk band
The Story So Far The Story So Far may refer to: __NOTOC__ Books * ''The Story of Far'' (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.


Notable people

James "Grizzly" Adams James may refer to: People * James (given name) * James (surname) * James (musician), aka Faruq Mahfuz Anam James, (born 1964), Bollywood musician * James, brother of Jesus * King James (disambiguation), various kings named James * Prince James ...
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 acquisition project of Save Mount Diablo. The Mount Diablo Ranch, or Diablo Ranch, was owned by Robert Noble Burgess, who founded the community of Diablo and built the mountain's first auto roads. On May 24, 1928, the Mount Diablo Ranch, or Diablo Ranch, ownership by Walter Paul Frick), a millionaire, who lived in Diablo, from Mt. Diablo Development company, for $50,000, was announced. Walter Paul Frick 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 David Warren Brubeck (; December 6, 1920 – December 5, 2012) was an American jazz pianist and composer. Often regarded as a foremost exponent of cool jazz, Brubeck's work is characterized by unusual time signatures and superimposing contrasti ...
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 * Common black hawk, ''Buteogallus anthracinus'' * Cuban black hawk, ''Buteogallus gundlachii'' * Great black hawk, ''Buteogallus urubitinga'' * Mangrove black hawk, ''Buteogallus (anthracinus) s ...
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 ...
and his partner
Ken Hofmann Kenneth Harry Hofmann (February 15, 1923April 22, 2018) was an American builder, real estate developer, and philanthropist. He was an owner of the Seattle Seahawks of the National Football League from 1988 to 1997, in partnership with Ken ...
.


Legends and folklore

Mount Diablo has long been the site of numerous reports pertaining to
cryptozoology Cryptozoology is a pseudoscience and subculture that searches for and studies unknown, legendary, or extinct animals whose present existence is disputed or unsubstantiated, particularly those popular in folklore, such as Bigfoot, the Loch Ness ...
,
hauntings This is a list of locations that are (or have been) said to be haunted by ghosts, demons, or other supernatural beings throughout the world. Reports of haunted locations are part of ghostlore, which is a form of folklore. Argentina * Cinco ...
, 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 Phantom, phantoms, or the phantom may refer to: * Spirit (metaphysics), the vital principle or animating force within all living things ** Ghost, the soul or spirit of a dead person or animal that can appear to the living Aircraft * Boeing Phanto ...
black " panthers" 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 A general officer is an Officer (armed forces), officer of high rank in the army, armies, and in some nations' air force, air and space forces, marines or naval infantry. In some usages, the term "general officer" refers to a rank above colone ...
Mariano Guadalupe Vallejo Don Mariano Guadalupe Vallejo (July 4, 1807 – January 18, 1890) was a Californio general, statesman, and public figure. He was born a subject of Spain, performed his military duties as an officer of the Republic of Mexico, and shaped the tran ...
(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 A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...
was said to be found within a slab of
limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...
at a
mine Mine, mines, miners or mining may refer to: Extraction or digging *Miner, a person engaged in mining or digging *Mining, extraction of mineral resources from the ground through a mine Grammar *Mine, a first-person English possessive pronoun M ...
on Mount Diablo.


See also

* List of California county high points *
List of summits of the San Francisco Bay Area This is a list of named summits in the nine-county San Francisco Bay Area that are more than above sea level. Note that there are no natural features above in the city of San Francisco. Unless otherwise referenced, all data are from the Geogra ...


Notes


References

*


External links

* *
Save Mount Diablo land trust and conservation organization home page
*

an

Panoramic views from the summit of Mount Diablo. Mediacom. {{DEFAULTSORT:Diablo, Mount Bay Miwok 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 Sacred mountains of the United States 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 Places in Native American mythology