The Cascade Mountains to the east of the Klamath Mountains are formed from volcanic activity in the region. The region is also known as the Cascade Volcanic Arc due to the presence of many dormant volcanoes, notably in the vicinity of Lassen Peak. Lassen rises to a height of about 2000 feet and last erupted in 1915. Mount Shasta, the second highest peak in the Cascade Mountains, is believed by geologists to be a dormant volcano. It is known to erupt once every 600-800 years. To the east of the Cascades, is the Modoc Plateau area, which was formed from the volcanic activity in the Cascades.
South of the Cascade Mountains and the Modoc Plateau, is the Sierra Nevada mountain range. The Sierra Nevada range, a batholitic landform, runs for over 400 miles from north to south. At 14,494 feet, Mt. Whitney is the highest elevation in all the 48 lower states of the USA. The mountain range has about 10 other peaks with an elevation of over 14,000 feet. Three national parks, the Kings Canyon National Park, the Sequoia National Park, and the Yosemite National Park are located in the Sierra Nevada Mountains. The Yosemite National Park is a UNESCO World Heritage Site. Lake Tahoe is the largest lake of this region. This 193 square mile large lake is located at an elevation of 1,640 feet. Owens Lake and Mono Lake are other lakes in Sierra Nevada.
The Central Valley forms the heartland of the country, flanked by the Sierra Nevada to the east and the Coast Ranges to the west. The valley itself is about 450 miles long. The Sacramento and San Joaquin rives crisscross the valley making it incredibly fertile. The Central Valley is also the agricultural hub of the state. The rivers form a delta and drain into the San Francisco bay. The Tehachapi Mountains extending from the Sierra Nevada virtually seal the Central Valley to the south.
The Coastal Ranges, to the west of the Central Valley seem to rise right from the coastline. The Diabolo Range, Santa Cruz Mountains, and Santa Lucia Ranges go to make the Coastal Ranges. The southern section of the Coastal Ranges is called Sierra Madre Mountains and San Rafael Mountains. Mount Pinos and Junipero Serra Peak are some of the important peaks in the Coastal Ranges. The Coastal Ranges are punctuated by many fertile valleys such as the Napa Valley, the Santa Clara valley, and the Salinas Valley. The coastal region to the west of these ranges (including the San Francisco Bay area) is the most populous region in California. Many fast-flowing creeks and rivers originate in the Coastal Ranges and flow into the valleys. The coastal belt is also home to redwood forests such as the Redwood National Park, a UNESCO Heritage site.
This area is also affected by the presence of many earthquake causing fault lines. The San Andreas Fault, running through California, is a major fault line. It enters the country through this region. The San Francisco Bay area is adversely impacted by the presence of the Hayward Fault and Los Angeles by the San Gabriel fault. This makes almost all of California extremely susceptible to catastrophes as caused by the San Francisco earthquake in 1996.
The Santa Ynez Mountains, the Santa Susana Mountains, the San Gabriel Mountains, and the San Bernardino Mountains make up the Transverse Ranges that geographically divide north and south California. Mount San Gorgonio, at 11,499 feet, is one of the highest elevations of the San Bernardino Mountains. The Transverse Ranges, unlike the other mountain ranges of California run east-west.
South of the Transverse Ranges are the Peninsular Ranges. The northern fringe of this region is a fertile basin formed by the rivers San Gabriel, Santa Ana, and Los Angeles. The cities of Los Angeles and San Diego are located in this region. East of the basin are the mountain ranges. The Peninsular Ranges are made up of the Laguna Mountains, the Palomar Mountain Range, the Santa Ana Mountains, the San Jacinto Mountains, and the Santa Rosa Mountains.
East of the Sierra Nevada is the Basin and Range region that extends into Oregon and Nevada. This region contains the high peaks of White Mountains, Inyo Mountains, and Panamint Mountains and also Death Valley. Death Valley is the lowest point in the USA and lies 282 feet below sea level.
To the south-east extreme of California is the Mojave Desert which covers over 25,000 square miles of Californian territory. Vegetation is sparse and most of the region is at an elevation of more than 2,000 feet above sea level. To the south of the state is the Colorado Desert that extends into Mexico. The Imperial Valley is one region in Baja California which is highly irrigated and agriculturally productive.
The Channel Islands, Anacapa Island, San Miguel Island, Santa Cruz Island, Santa Rosa Island, San Clemente Island, San Nicolas Island, Santa Barbara Island, and Santa Catalina Island are located off the coast of California.
Most of California enjoys mild climate and equitable rainfall. The coastal regions can get rather cold in winter months. The desert regions are low on rainfall and the temperature soars up to 130°F. The cities of Los Angeles and San Diego have average temperatures ranging between 50°F and 60°F and are very pleasant.