The Oregon High Cascades has a picture for you. From early spring, the heart of winter, you will enjoy your visit to our pictures. We use a high contrast style to bring out an artistic aspect to our vivid colored High Cascade Mountain pictures. Just click on any picture to view the file.
In the United States, the Cascade Range extends from northern California to northern Washington. In Oregon, south of Mount Hood, the Cascade Range is 50 to 120 kilometers wide, and is composed primarily of upper Eocene to Quaternary volcanic, volcaniclastic, sedimentary, and igneous intrusive rocks. The crest of the Cascade Range is generally at an altitude of 1,500 to 2,000 meters, with several of the high volcanoes exceeding 3,000 meters (Callaghan and Buddington, 1938; Sherrod, 1986). The high stratovolcanoes and volcano remnants of the central Oregon Cascade Range include Mount Jefferson, Three Fingered Jack, Mount Washington, the three volcanoes of the Three Sisters, Broken Top, Mount Bachelor, Diamond Peak, Mount Thielsen, and Crater Lake Caldera (Mount Mazama). These are all Pleistocene stratovolcanoes of rhyolitic to basaltic composition and are formed mostly of interlayered thin lava flows and pyroclastic deposits overlying cinder cone cores. Of the large stratovolcanoes, there has been Holocene volcanic activity on the summit and flanks of South Sister and at Mount Bachelor as well as the caldera-forming eruptions of Mount Mazama (Taylor, 1981; Taylor and others, 1987; Scott, 1989). The general conical morphology is best preserved on the volcanoes of Middle Sister, South Sister, and Mount Bachelor; the rest have been deeply eroded by Pleistocene glaciation.
Western Oregon has a temperate maritime climate that is dominated by winter Pacific frontal systems moving eastward across the State. The Cascade Range is a major orographic barrier that intercepts much of the eastward-flowing moisture. Generally warm and dry summers result from northward expansion of the eastern Pacific high pressure system and diversion of the prevailing westerlies to the north. Consequently, precipitation generally occurs during the winter and is greatest at high altitudes. Annual precipitation is about 3,500 to 4,000 millimeters at the highest elevations within the Three Sisters and Mount Jefferson Wilderness Areas (Taylor, 1993) and falls mostly as snow. At Crater Lake, 90 percent of the 1,620 millimeters of annual precipitation falls between October 1 and May 31. Annual precipitation decreases eastward across the Oregon Cascade Range, diminishing from more than 2,500 millimeters on the western slopes to less than 400 millimeters within 30 kilometers east of the range crest (Taylor, 1993).
The highest peaks of the central Oregon Cascade Range rise above treeline, which is about 2,200 meters above sea level on the north side of Mount Jefferson, about 2,300 meters on the north side of south Sister, and 2,500 meters on the south side of Broken Top. The tallest trees of the subalpine forests and parks near timberline are mountain hemlock (Tsuga mertensiana) and whitebark pine (Pinus albicaulis).