Yosemite National Park reaches across the western slopes of the Sierra Nevada mountain chain. Yosemite was designated a World Heritage Site in 1984, and is internationally recognized for its spectacular granite cliffs, waterfalls, clear streams, Giant Sequoia groves, and biological diversity. About 89% of the park is designated wilderness. Although not the first designated national park, Yosemite was a focal point in the development of the national park idea, largely owing to the work of people like John Muir.
The geology of the Yosemite area is characterized by granitic rocks and remnants of older rock. About 10 million years ago, the Sierra Nevada was uplifted and then tilted to form its relatively gentle western slopes and the more dramatic eastern slopes. The uplift increased the steepness of stream and river beds, resulting in formation of deep, narrow canyons. About 1 million years ago, snow and ice accumulated, forming glaciers at the higher alpine meadows that moved down the river valleys. Ice thickness in Yosemite Valley may have reached 4,000 feet during the early glacial episode.
Grand Classroom trips explore the valley and learn about the human history as well as the natural history. Depending on the weather, snowshoeing may also be on the itinerary.
Yosemite HD from Project Yosemite on Vimeo.