Mount Diablo

Mount Diablo

Aerial view of the Los Medanos foothills and Mount Diablo from over Suisun Bay at Concord, California

Mount Diablo is a mountain in Contra Costa County, California in the San Francisco Bay Area, located south of the town of Clayton and northeast of Danville. It is an isolated 3,849-foot (1,173 m) upthrust peak that is visible from most of the San Francisco Bay Area and much of northern California. Mount Diablo appears from many angles to be a double pyramid and includes many subsidiary peaks, the largest and closest of which is the other half of the double pyramid, North Peak, nearly as high in elevation at 3,557 feet (1,084 m).

The peak is the centerpiece of Mount Diablo State Park, a state park of approximately 20,000 acres (80 km²) in area. The park was the first public open space of a complex -- according to Save Mount Diablo -- now including 38 preserves, including adjacent and nearby city open spaces, regional parks, watersheds, etc., buffered in some areas with private lands protected with conservation easements. Preserved lands on and around Mount Diablo total more than 90,000 acres (360 km²).

Except for distant views from the Central Valley, Mt. Diablo's northwestern double pyramid view is most familiar to California residents. This view however includes a minor part of the mountain's acreage, most of which stretches east and southeast from the summit through Altamont Pass to the rest of the northern Diablo range.

Geography

The summit of Mount Diablo itself is accessible by motor vehicle, hiking, running, or bicycle (the record time by bike from The Athenian School in the town of Diablo to the summit is just under 45 minutes; casual bicycle riders should bring plenty of food and water and wear sunscreen).

On a clear day, it is possible to view the mountains of the Sierra Nevada and the southernmost mountain of the volcanic Cascade Range, Mount Lassen more than 180 miles (289 km) away. Owing to the earth's curvature it is not possible to see the larger Mount Shasta, although Half Dome in Yosemite National Park, about 125 miles (201 km) to the east, can be viewed with a telescope when the atmosphere is exceptionally clear. Despite historic claims that the mountain's viewshed is the largest in the world—or second largest after Mt. Kilimanjaro—these claims are unfounded. It is however, one of the largest viewsheds in the Western United States.

The best views can be found the day after a winter storm; during the summer visibility can be somewhat hazy. From Stockton, on a clear day, and from many other places similarly distant, Mt. Diablo and its range can be seen, along with the Sierra Nevada on the eastern horizon. Approximately one mile northeast of the summit is North Peak at 3,557 feet (1,084 m).

View of Mt. Diablo from Concord; The main peak is at right, North Peak at left and Mt. Zion at center

Cultural history

Mount Diablo is sacred to many California Native American peoples; according to Miwok mythology and Ohlone mythology, it was the point of creation. Mount Diablo and Reed’s Peak were surrounded by water. From these two islands the creator Coyote and his assistant Eagle-man made Indian people and the world.

Earliest names

View of Mt. Diablo's North Peak from the main peak

Information on prior names for Mount Diablo is found at the organization, Save Mount Diablo: "About 25 independent tribal groups with well-defined territories lived in the surrounding East Bay countryside. Their members spoke dialects of three distinct languages: Ohlone, Bay Miwok, and Northern Valley Yokuts... Most of Mount Diablo, including its peak, was within the homeland of the early Volvon, a Bay Miwok-speaking group, and as early as 1811, the mountain was called [in Spanish] Cerro Alto de los Bolbones (High Point of the Volvon). The Chochenyo-speaking Ohlone from the Mission San Jose and East Bay area, called the mountain Tuyshtak, meaning 'at the day'. The Nisenan of the Sacramento Valley called it Sukkú jaman, or as Nisenan elder Dalbert Castro once explained, 'the place where dogs came from in trade'." A Southern Miwok name was Supemenenu.

It has been suggested that an early Indian name for the mountain is Kawukum or Kahwookum, but there is no evidence to confirm the assertion. According to Indian historian Bev Ortiz and Save Mount Diablo: "The name “Kahwookum” was made up in 1866—with no real Indian 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” and attributed to Diablo area Volvon Indians."

Current name

The conventional view is that the peak derives its name from the 1805 escape of several Chupcan Native Americans from the Spanish in a nearby willow thicket. The natives appeared to disappear, and the Spanish soldiers thus gave the thicket the name "Monte del Diablo", meaning "thicket of the devil."

General Mariano G. Vallejo, in an 1850 report to the California State legislature, gave this much romanticized story of the derivation of the name of Mt. Diablo from its Spanish to Anglo form, related to the mountain and an evil spirit. Vallejo’s report could be interpreted to align with Gudde’s account. (Kyle, and Ortiz)

This name was later applied to Don Salvio Pacheco's Rancho Monte del Diablo, the present-day site of the city of Concord. The name's origin was misinterpreted by English-speaking newcomers to refer to the mountain rather than the thicket.

The name Monte del Diablo (‘devil’s woods’) appears on the Plano topográfico de la Misión de San José about 1824, where there was an Indian rancheria perhaps near a thicket at the approximate site of the present town of Concord. {Pacheco} On August 24, 1828, the name was applied to the Monte del Diablo land grant for which Salvio Pacheco had petitioned in 1827.

In 2005, a man from the neighboring town of Oakley, petitioned the federal government to change the name of the mountain, claiming it offended his Christian beliefs (despite the fact that the mountain was named by Christian settlers). He initially suggested renaming the mountain Mt. Kawukum, and later, Mt. Yahweh. Other renaming suggestions by other individuals included Mount Miwok and Mount Ohlone, after local Indian tribal names. Eventually, the U.S. Board on Geographic Names rejected the petitions, saying there was no compelling reason to change the name.

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 Meridian lines intersect — for cadastral surveys of a large area. Subsequent surveys in much of California, Nevada and Oregon were located with reference to this point. Toll roads up the mountain were created in 1874 by Joseph Seavey Hall and William Camron (sometimes "Cameron"); Hall's Mt. 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, operated through the 1880’s, abandoned 1895, burned c. 1901). An aerial navigation beacon, the Standard Diablo tower was erected by Standard Oil at the summit in 1928. The beacon became known as the "Eye of Diablo" and was visible for a hundred miles.

Parks and protection of land

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, '50s and '60s. Significantly, botanist Mary Leolin Bowerman (1908-2005), founder of Save Mount Diablo in 1971, published her Ph.D in 1936 at the University of California, Berkeley and then in 1944 the 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, as well as the origin of many of the park's place names.

Mt. Diablo from the Berkeley-Oakland hills

In 1954, KOVR erected its television transmitter tower on the mountain. One of the workers involved in the project said that parts of the tower were trucked up to the summit and assembled there. Based in Stockton, the station eventually became affiliated with ABC and was known for its popular "Toonytown" program hosted by Art Finley. With the completion of the mammoth television tower near Elk Grove, KOVR moved its transmitter there and later relocated its studios to Sacramento.

This initial park has been greatly expanded over the years. 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 6,788 acres (27.5 km²) and was the only park in the vicinity of the mountain. In 2007 the state park totaled almost 20,000 acres (80 km²), and with 38 parks and preserves on and around the mountain, Diablo's public lands total more than 90,000 acres (360 km²). 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 Preserves. It also adjoins protected areas owned or controlled by local cities such as the Borges Ranch Historic Farm, the Concord Naval Weapons Station (now in the process of being converted to non military use), Indian Valley, Shell Ridge Open Space and Lime Ridge Open Spaces near city of Walnut Creek, and east to the Los Vaqueros Reservoir watershed, The new Cowell Ranch State Park, and Black Diamond Mines Regional Preserve, are among the open spaces stretching back 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, with significant exceptions 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; in the upscale development of Blackhawk for example, and some 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. 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 must accurate and up-to-date map of Mount Diablo's more than 90,000 acres (360 km²) of protected lands, including 100 access points, 520 miles of trail and 400 miles of prviate fire roads. In accompanying press materials and news articles updated acreages and trail mileages were discussed.

Natural history

Geology

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 slip-strike 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 milimeters each year.

Mt. Diablo is a double pyramid and some say that it resembles a volcano (but is not). Here is a summary of its geology by local resident Cleet Carlton:

Mt. Diablo is a geologic anomaly located approximately 30 miles (50 km) east of San Francisco. 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 Pacific Plate dating back to the Jurassic and Cretaceous Periods, between 190 and 90 million years ago. During this time, the Pacific Plate was subducting beneath the North American Continent and 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 Mt. Diablo Ophiolite and Metasediments of the Franciscan Complex 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 150 to 66 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 is ongoing and will continue to change shape of Mt. Diablo, along with the rest of the Coast Ranges.

The summit area of Mt. Diablo is made up of deposits of gray sandstone (graywacke), chert, oceanic volcanic basalts (greenstone) and a minor amount of shale. The hard red Franciscan chert is sedimentary in origin and rich in microscopic radiolaria fossils. In the western foothills of the mountain there are large deposits of younger sandstone rocks rich in seashells, severely tilted and in places forming dramatic ridgelines.

There are deposits of glassmaking-grade sand and lower-quality coal to the north of the mountain, which were formerly mined in the 1800s and early 1900s, but are now open to visitors as the Black Diamond Mines Regional Preserve. Guided tours of sand and coal mines are provided here.

Vegetation

View SW across the park from near the summit of Mt. Diablo

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 Mt. Diablo manzanita (Arctostaphylos auriculata), Mt. Diablo globe lily (Calochortus pulcellus) and Diablo sunflower (Helianthella castanea). The park includes substantial thickets, isolated examples, and mixed ground cover of western poison-oak. (It is best to learn to 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 there are stands of Knobcone pine, Foothill pine, and Coulter pine (for which the park and nearby Black Diamond Mines Regional Preserve mark the northern extreme of the range).

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. Species of plants endemic to the Mount Diablo area are Brewer's Phacelia (Phacelia breweri) at Mt Diablo and the Mt. Hamilton Range of The Diablo mountains; Chaparral Harebell (Campanula exigua), Mt Diablo and Hamilton Range; Contra Costa Manzanita (Arctostaphylos manzanita ssp. Laevigata), Mt Diablo, Black Diamond, Morgan Territory; Jepson's Coyote Thistle, Mt. Diablo; Mt Diablo Buckwheat (Eriogonum truncatum) presumed extinct until 2005, historical range of Mt Diablo to Antioch, with an old record from Solano County as well; Mt. Diablo Manzanita (Arctostaphylos auriculta), Mt Diablo & adjacent uplands in Contra Costa County; Mt. Diablo Sunflower (Helianthella castanea), common on Mt. Diablo proper, and also occurring on adjacent uplands, parts of the East Bay hills, historically on the San Francisco peninsula, Mt. Diablo Fairy Lantern (Calochortus pulchellus), Mt Diablo & adjacent uplands, also Briones to Carquinez, and possibly Solano County; Mt. Diablo Bird's Beak (Cordylanthus nidularius), restricted to serpentine on Mt Diablo; Mt. Diablo Phacelia (Phacelia phacelioides), Mt. Diablo and Mt. Hamilton Range (known from fewer than 20 occurrences, many historical); Mt. Diablo Jewel Flower (Streptanthus hispidus), only Mt. Diablo proper; Rock Sanicle (Sanicula saxatilis), Mt. Diablo and Northern Hamilton Range.

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, California Ground Squirrels, Fox Squirrels and Grey Foxes; many other mammals including Mountain lions are present. It is a chief remaining refuge for the threatened Alameda Whipsnake, California red-legged frog. Less common wildlife species include the reintroduced peregrine falcon, ringtail cats, and to the east American badgers, San Joaquin kit fox, roadrunners, California tiger salamander, and burrowing owls. 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 you may encounter the male Tarantula spider (Aphonopelma Smithi) as he seeks a mate. These spiders are harmless, unless severely provoked, however the bite is only as bad as a bee sting. More dangerous are black widow spiders, far less likely to be encountered in the open.

And in the wintertime, between November and February, you can witness the Bald Eagle and the Golden Eagle. These birds are less easily seen than many raptors; Golden Eagles particularly fly at high elevations. Mt. Diablo, however, 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 Monument, 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 Poison Oak, Hop Tree, 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 article.

Facilities

Summit building, Mt. Diablo, constucted by the CCC from 1939-1942

Gate houses 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 gate houses are not operating, the 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. On busy days it is advisable to park at the large parking lot near the summit and take a short walk up to the summit. At this lot you may encounter hang gliders ready for launch. There is also a restroom here and at the summit.

From the elevation of the lower lot there is also a level wheelchair-accessible trail with interpretive stations that extends part way around the mountain. There are numerous hiking trails and some paths available for mountain biking and horse riding.

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.

Claims about viewable area

According to a sign at the summit, it is possible to view the second greatest surface area seen from any peak in the world, exceeded only by the 19,340 foot (5,895 m) Mount Kilimanjaro in Africa. This myth was promulgated by early real estate promoter Robert Noble Burgess, who built the first auto roads to Diablo's summit, as a draw to his Mt. Diablo Estates project, c. 1914-1917. The Mt. Kilimanjaro qualifier was first added in the 1928 Standard Oil Bulletin, which described the new Standard Diablo (SD) Tower.

The lack of surrounding peaks does indeed give the intimidating mountain an immense view. However, Diablo's relatively low height and the curvature of the earth limit the visible horizon over the sea and surrounding plains to approximately 78 miles (125 km). Beyond that, only ridges are visible and then only on their appropriately facing sides. Many higher peaks around the world offer greater general viewing distances over seas and flat plains.

One calculation shows that the viewshed from Mount McKinley (Denali) in Alaska is about three times greater. Nor is it plausible that more viewable area can be seen from the Diablo summit than any other peak in the lower 48 states. The viewshed east from Colorado summits (e.g. Pike's Peak) over the Great Plains is much greater. See the panorama external link at the foot of this page.

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 23.96 inches (60.86 cm). The most precipitation recorded in a month was 13.54 inches (34.39 cm) in February 1998. The greatest 24-hour precipitation was 5.02 inches (12.75 cm) on January 21, 1972. The average annual days with measurable precipitation is 65.3 days.

Snowfall at Mount Diablo Junction averages 1.2 inches (3.0 cm) each year. The most snowfall observed in a month was 17.0 inches (43.2 cm) in April 1975; that same month saw 6.0 inches (15.2 cm) in one day (April 4, 1975). The greatest snow depth was 3 inches (7.6 cm) 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.

Data-Collecting Note

It is important to note that the weather station is positioned at only about 55 percent of the mountain's height, and temperature and snow levels are notably different at the upper reaches of the mountain, where more snow and lower temperatures may have occurred, but simply not have been recorded. Nearby Bay Area mountains, like Mount Hamilton, have their weather stations virtually at the maximum height of the mountain. 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 400 feet (122 m). Wind speed, direction and temperature are measured at the peak and presented by an automatic telephone voice response system and 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.

Mount Diablo Art and Literature

Mt. 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 California College of Arts, the actions of the organizations Save Mount Diablo and the Mt. Diablo Interpretive Association, and area art centers, galleries, and museums. In modern times Mt. 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, Alexander Dumas, 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 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, 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 to commissioned works by the California Symphony.

Famous Residents

Mount Diablo has been the home of a number of 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 out of 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 Northgate entrance.

The area for the 6,500-acre (26 km²) 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 Mt. Diablo State Park. The remainder was developed as the community of Blackhawk by resident developer Ken Behring.

Events

Every year on December 7 the aircraft beacon atop the summit building is illuminated from sunset to dawn. A ceremony memorializing the attack on Pearl Harbor on this day in 1941 is held at the summit, with some of the few remaining survivors who are present. The public is welcome and visitors on this day should enter the park before 4:00 PM. General parking will be at the lower lot on these days, with a short uphill walk by trail or road to the summit. Visitors may leave later than usual — this is one of the few opportunities to view the sunset from the peak, weather permitting, without an overnight stay.

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 to the distant Sierra Nevada, 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 Mt. Diablo Challenge, an annual hill climb to the summit with more than 1,100 cyclists each October; and the Mt. 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, 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 icey conditions above.

Occasionally there will be public access to astronomical observations made by a local astronomy club. This club has been allocated a small parcel on the mountain and is developing a permanent observatory at this location. The instrument to be installed will have digital-imaging capabilities and visitors will be able to take home an astronomical image that they may display on their home computer system.

Mt. Diablo Challenge Bicycle Race

A cyclist riding up Mount Diablo.

The Mt. Diablo Challenge is a bicycle race held annually on the first Sunday in October. The race begins at the Athenian School at the base of the mountain and climbs 3,249 feet (990.3 m) in 10.8 miles (17.4 km). The race typically draws between 800 to 1,100 riders each year who compete in a mass-start format. Bicycle riders of every age and ability are represented in the diverse 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 Mt. Diablo climb currently stands at 44 minutes, 58 seconds, 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.

References

• Information from the California State Parks leaflet on Mount Diablo State Park, issue 8/01, 2000.
• sfgate.com article

See also

• List of highest points in California by county

External links

• Mount Diablo page of the California State Parks official website
• Save Mount Diablo is a non-profit organization formed in 1971 which acquires land, responds to development proposals, creates recreational opportunities and conducts events and educational programs related to Mt. Diablo. SMD also publishes the most accurate regional recreation map of the Diablo parks.
• Mt. Diablo Interpretative Association, a non-profit organization working to help the public enjoy the Mount Diablo park
• Mount Diablo Astronomical Society
• Mount Diablo Observatory Association
• Sympathy for the Devil: The native plants of Mount Diablo deliver both tricks and treats.
• Check-Six.com - Story of the 1946 Crash of an Army C-45F on the northern face of Mt. Diablo
• Black Diamond Mines Regional Preserve
• MT. DIABLO CAM ~Live webcam~
• Old Borges Ranch demonstration farm
• Photos of Mount Diablo State Park
• Computer-generated summit panoramas North South index. Note comments in the "Geography" section on this page about the viewshed.
• Up and Down California in 1860-1864