San Gorgonio Mountain
San Gorgonio Mountain, also known locally as Mount San Gorgonio, or Old Greyback, is the highest peak in Southern California and the Transverse Ranges at . It is in the San Bernardino Mountains, east of the city of San Bernardino and north-northeast of San Gorgonio Pass. It lies within the San Gorgonio Wilderness, part of the Sand to Snow National Monument managed by the San Bernardino National Forest. Spanish missionaries in the area during the early 17th century named the peak after Saint Gorgonius. Since it is the highest point in a region which is separated from  higher peaks (e.g. in the Sierra Nevada) by relatively low terrain, San Gorgonio Mountain is one of the most topographically prominent peaks in the United States. It is ranked 7th among peaks in the 48 contiguous states and 18th overall. Like other high peaks in the Transverse Ranges, the mountain has a pyramid shape, with a steep north face and a slightly shallower south face. The mountain is large and broad; the summit plateau itself is one square-mile in area (2 km). In contrast to its spectacular but lower neighbor, San Jacinto Peak, San Gorgonio is not particularly craggy , and from a distance, it appears to be an extremely high hill, earning it the name of "greyback". Despite not being particularly striking in appearance during the summer, it is the only mountain in Southern California with a summit a significant distance above the tree line. As such its bright white winter snow cap, unobstructed by vegetation, makes the mountain noticeable from many miles away. The mountain hosts the longest recorded line of sight in the contiguous United States; it is plainly visible from the summit of Mount Whitney, away. Geography. San Gorgonio Mountain lies at the easternmost extremity of  the Transverse Ranges. The mountain is a heavily eroded, partially dissected plateau. Big Bear Lake, California is the largest city near San Gorgonio, and hosts two major ski resorts, as well as a popular summer get away for many southern Californians that utilize the lake for boating swimming, and fishing. Geology. The shape of the mountain is influenced by a series of steeply dipping thrust faults on the north face of the mountain. The south side of the mountain contains river canyons typical of a dissected plateau. The mountain is a massive block of quartz monzonite, which sits on an  ancient platform of Precambrian gneissic rocks. Glacial and fluvial deposits dominate the surface of the lowest part of the mountain. Hydrology. Three major Southern California rivers have their source on San Gorgonio Mountain: the Santa Ana River, the Whitewater River, and the San Gorgonio River. Jenks Lake, on the north slope of the mountain, is one of the few perennial lakes in Southern California. San Gorgonio Mountain sits on the Great Basin Divide, which separates streams that flow into the basins of the Basin and Range Province from rivers that flow into the Pacific Ocean. Climate. The climate on most  of the mountain is "Csb" (Warm-summer Mediterranean) under the Köppen climate classification. The summit of San Gorgonio has an Alpine climate ("ET"), as no month in that area has an average temperature greater than . Hiking. Like most other peaks in the Transverse Ranges, the summit is a technically easy class 1 hike. Several trails lead to the broad summit of San Gorgonio Mountain, which rises a few hundred feet (100 m) above the tree line. Most routes are very strenuous and require well over of elevation gain. The trail leading from the Fish Creek Trailhead to San Gorgonio Mountain  has about of gain, less than the routes from the South Fork and Vivian Creek trailheads. Hikers should always take caution because some junctions on this trail are not well marked. Aircraft wreckage. On December 1, 1952, a Douglas C-47, serial number 45-1124, crashed at the level on the eastern face of the mountain. The C-47 was en route from Offutt Air Force Base, Nebraska to March Air Force Base near Riverside, California when it struck the mountain at night in the middle of a storm. "The aircraft was last heard from at 9:51 p.m. Pacific Standard Time, Monday ." Thirteen people died. Nearly one month after the C-47 accident a Marine Corps HRS-2 helicopter, bureau number 129037, crashed on the mountain in coordination of the efforts of recovering the victims. The three crewmen of the helicopter survived the impact. Most of the wreckage of the two aircraft remain on the mountain and are accessible via the Fish Creek Trailhead or the South Fork Trailhead. In more recent years, the mountain claimed the lives of Frank Sinatra's mother, Dolly (January 6, 1977) and Dean Paul Martin (March 21, 1987), son of Dean Martin, in unrelated plane crashes. Martin was  an Air National Guard pilot and the McDonnell Douglas F-4C he was flying disappeared in a snowstorm and the wreckage was found on the mountain several days later.