Diablo Range

Diablo Range
Mount Hamilton
Highest point
Elevation	5,240 ft (1,600 m)
Dimensions
Length	180 mi (290 km) north-south from Carquinez Strait to Polonio Pass
Width	20 mi (32 km)
Geography
Diablo Range Location of the Diablo Mountain Range in California, U.S.[1]
Country	United States
State	California
Region	USGS  San Benito Mountain

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 area at its southern end.

Geography

The Diablo Range extends from the Carquinez Strait in the north to Orchard Peak and Polonio Pass in the south, near the point where State Route 46 crosses over the Coast Ranges at Cholame, as described by the United States Geological Survey (USGS). It is bordered on the northeast by the San Joaquin River, on the southeast by the San Joaquin Valley, on the southwest by the Salinas River, and on the northwest by the Santa Clara Valley.^[1] The USGS designation is somewhat ambiguous north of the Santa Clara Valley, but on USGS maps, the range is shown as the ridgeline which runs between its namesake Mount Diablo southeastward past Mount Hamilton. Geologically, the range corresponds to the California Coast Ranges east of the Calaveras Fault in this northern section. For much of its length, it is paralleled by other sections of the California Coast Ranges to the west, the Santa Cruz Mountains across the southern San Francisco Bay and Santa Clara Valley, and the Santa Lucia Range across the Salinas Valley.

The range passes through Contra Costa, Alameda, San Joaquin, Santa Clara, Stanislaus, Merced, San Benito, Fresno, Monterey, and Kings Counties, and ends in the northwesternmost extremity of Kern County.

Topography

Though the average elevation is about 3,000 feet (910 meters), a summit of over 2,300 feet (700 m) is considered high, mainly because the range is mostly rolling grassland and plateaus, punctuated by isolated peaks. Plateaus are usually at about 2,000–3,000 feet (610–910 m). Hills rise to about 1,000 feet (300 m), while foothills such those in the Santa Clara Valley, Livermore Valley and San Joaquin Valley are typically 400–1,000 feet (120–300 m).

Canyons are usually 300–400 feet (91–122 m) deep; valleys are often deeper but less steep-sided. Peaks often have high topographic prominence, as they are surrounded by valleys or lower hills or plateaus. Streams draining the eastern slopes of the Diablo Range include Hospital Creek and Ingram Creek. Stream draining the western slopes include Alameda Creek and Coyote Creek.

Peaks

The Diablo Range's peaks and ridges are between 2,517–5,241 feet (767–1,597 m) and are distinct landmarks. Mount Diablo (3,849 feet (1,173 m)), San Benito Mountain (5,241 feet (1,597 m)), Mount Hamilton Ridge (4,230–4,260 feet (1,290–1,300 m)), and Mount Stakes (3,804 feet (1,159 m)) are four of the highest peaks in the range.

View of Mt. Diablo from Concord. Main peak at right, North Peak at left, Mt. Zion at center (scroll image L/R to view)

Human elements

The Diablo Range is paralleled for much of its distance by U.S. Route 101 to the west and by I-5 to the east. Major routes of travel through the range include:

• North of the range
  • Amtrak San Joaquin
• Willow Pass
  • State Route 4
  • BART Yellow Line
• Altamont Pass
  • Union Pacific Railroad/Altamont Corridor Express
  • I-580
• Sunol Valley
  • State Route 84
  • I-680
• Patterson Pass
• Corral Hollow Pass
• Mount Hamilton
  • State Route 130
• Pacheco Pass
  • State Route 152
  • Future California High-Speed Rail
• Panoche Pass
• State Route 198
• Cottonwood Pass (State Route 41)
• Polonio Pass (State Route 46)

A sparsely used gravel road is the highest road in the range, with its highest point being on San Benito Mountain at over 5,000 feet.^{[citation needed]}

The Diablo Range is largely unpopulated outside of the

Protected areas

Most of the range consists of private ranchland, limiting recreational use. However, the range does contain several areas of parkland, including

Since the range lies around 10–50 miles (16–80 kilometers) inland from the ocean, and other coastal ranges like the Santa Lucia Range and the Santa Cruz Mountains block incoming moisture, the range gets little precipitation. In addition, the average elevation of 3,000 feet (910 m) is not high enough to catch most of the incoming moisture at higher altitudes.

Winters are mild with moderate rainfall, but summers are very dry and hot. Areas above 2,500 feet (762 m) get light to moderate snow in the winter, especially at the highest point, the 5,241 ft (1,597 m) San Benito Mountain in the remote southeastern section of the range. However, though sites at the lower end get annual snowfall, it is typically light and melts too fast to be noticed. Once or twice a decade there is seriously deep and long lasting snowfall.

Mercury contamination near the southern end of the range is an ongoing problem, due to the

The range's riparian zones have such trees as bigleaf maple (Acer macrophyllum), white alder (Alnus rhombifolia), California bay (Umbellularia californica), and California sycamore (Platanus racemosa).^[4]

The most common trees are

The Diablo Range attracts far more raptors than coastal forests, such as red-tailed hawks. Golden eagle nesting sites are found^[5] in the Diablo Range, reaching their highest density in southern Alameda County.^[6][7][8]

The

A species of millipede, Illacme plenipes, is endemic to the southern Diablo Range. First described in 1926, then not seen again until 2005, the species has more legs than any other species of millipede, with one specimen having 750.^[10]

See also

• Mountain ranges of the San Francisco Bay Area
• Rancho Cañada de Pala
• Rancho Santa Teresa

References