Diablo Range

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The Diablo Ranges is a mountain range in western California, part of the Pacific Coast Ranges. According to the USGS, it extends from the Carquinez Strait in the north to Orchard Peak in the south, near the point where State Route 46 crosses over the Coast Ranges at Cholame. 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 their maps, the range is shown as the ridgeline which runs between its namesake Mount Diablo southeastward to Mount Hamilton. Geologically, the range corresponds to the Coast Ranges east of the Calaveras Fault in this northern section.

Important peaks include Rose Peak, Mount Diablo, San Benito Mountain, Copernicus Peak, Mount Hamilton, and Mount Stakes.

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.

Major routes of travel through the range include SR 4 (north of the range), I-580, SR 152, SR 198, and SR 46/SR 41 (south of the range). Important passes include Altamont Pass, Pacheco Pass, and Polonio Pass. It is paralleled for much of its distance by U.S. Route 101 to the west and by I-5 to the east. A sparsely used gravel road is the highest road in the range, with its highest point being San Benito Mountain at 5,200 feet (1,585 m).

The Diablo range is largely unpopulated, particularly outside of the San Francisco Bay Area. Major nearby communities include Antioch, Concord, Walnut Creek, Pleasanton, Livermore, and the Central Valley city of Tracy. In the South Bay, communities near (though not in) the range are Milpitas, eastern San Jose, Morgan Hill, and Gilroy. South of Pacheco Pass, the only major nearby communities (those with a population over 15,000) are Los Baños, and Hollister. The small town of Coalinga may also be notable for its location on SR 198, one of the few routes through the mountains.

Most of the range consists of private ranchland, limiting recreational use. However, the range does contain several areas of parkland, including Mount Diablo State Park, Joseph D. Grant County Park, Henry W. Coe State Park, and the BLM's Clear Creek Management Area.

[edit] Environmental aspects

The Diablo Range generally has a chaparral and California oak woodland environment, with stands of conifers appearing above 4,000 feet (1,219 m). Since the range lies around 10 to 50 miles (16 to 80 km) 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 to 4,000 feet (915 to 1,219 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. Golden Eagle nesting sites are found^[1] in the Diablo Range.

Some streams draining the eastern slopes of the Diablo Range include Hospital Creek and Ingram Creek.

[edit] References