The San Gorgonio Pass, or Banning Pass, is a elevation gap on the rim of the Great Basin between the San Bernardino Mountains to the north and the San Jacinto Mountains to the south. The pass was formed by the San Andreas Fault, a major transform fault between the Pacific plate and the North American plate. The tall mountain ranges on either side of the pass result in the pass being a transitional zone from a Mediterranean climate west of the pass, to a Desert climate east of the pass. This also makes the pass area one of the windiest places in the United States, and why it is home to the San Gorgonio Pass wind farm. It serves as a major transportation corridor between the Greater Los Angeles region and the Coachella Valley, and ultimately into Arizona and the United States interior. Both Interstate 10, and the Union Pacific Railroad, utilize the pass. When the rail line was completed in January, 1883, by the Southern Pacific Railroad, it was billed as the second U.S. transcontinental railroad. The pass is one of the deepest mountain passes in the 48 contiguous states, with the mountains to either side rising almost above it. San Gorgonio Mountain, taller but farther away and less visible, is at the northern side of the pass, and Mount San Jacinto is on the southern side. Mount San Jacinto has the fifth-largest rock wall in North America, and its peak is only six miles south of Interstate 10. The pass is also referred to as the Banning Pass due to the town of Banning being located about 6.5 miles east of the pass summit. The city itself was named for Phineas Banning who founded the town. Geology The pass is the major geologic divide between the igneous batholithic Peninsular Ranges and the Transverse Ranges, which is a massive fault block composed of diverse forms of rock. According to Yule 2009, the pass is the single "largest discontinuity along the San Andreas fault". One active branch of the San Andreas Fault passes through the San Gorgonio Pass roughly parallel and just to the north of interstate 10. Active parts of the Banning, the Garnet Hill and the San Gorgonio Pass Thrust faults are associated with the San Andreas Fault through the Pass. Together, these faults accommodate strike-slip and reverse slip that contributes to both uplift of the San Bernardino