![]() Bull Run is separated from the mountain by a prominent ridge and is fed largely by rainfall, which ranges from 130 inches a year at lower elevations to 170 inches higher up. The glaciers are not the source of drinking water for the City of Portland, which gets its water from the Bull Run Watershed, a 102-square-mile protected watershed in the Mount Hood National Forest northwest of Mount Hood proper. The mountain is also the source of five major rivers- Salmon, Zigzag, Sandy, Hood, and White-and is the centerpiece of the Mount Hood National Forest, a million-acre forest that more than four million people visit each year. A twelfth glacier, christened the Salmon Glacier in 1924 and later renamed the Palmer Glacier, lost enough of its volume and mobility over the twentieth century to be widely regarded as a snowfield. Mount Hood is host to eleven named and active glaciers: Zigzag, Reid, Sandy, Glisan, Ladd, Coe, Langille, Eliot, Newton Clark, White River, and Coalman. ![]() Although the mountain has not erupted since then, vents on its upper reaches, called fumaroles, still emit sulfurous steam, and minor earthquakes occur frequently deep beneath the mountain. The most recent major eruption, estimated to have occurred in the 1780s, sent a massive lahar down the Sandy River and left behind Crater Rock, a 550-foot-high lava dome on the mountain’s south side. In the past 2,000 years, Mount Hood has experienced three eruptive periods: the Timberline period, just over 1,500 years ago the Zigzag period, about 600 years ago and the Old Maid period, between the 1760s and the early 1800s. ![]() Notable natural features include Cooper Spur, Illumination Rock, Barrett Spur, Mississippi Head, McNeil Point, Yocum Ridge, and Cathedral Ridge.Įruptions on Mount Hood have been characterized less by powerful explosions than by the gradual building and collapse of lava domes, pyroclastic flows, and volcanic mudflows known as lahars. At its highest, Mount Hood topped 12,000 feet, with ice and erosion reducing the peak to its current height. Over the ensuing millennia, further eruptions continued to shape and give rise to the mountain. Eruptions and GlaciersĬomposed primarily of andesite and dacite, Mount Hood began to form during volcanic eruptions between 500,000 and 700,000 years ago. Mount Hood has played a central role in the geology, history, natural environment, and culture that have helped shape northwest Oregon and the entire Pacific Northwest. ![]() At 11,244 feet, it is the highest point in Oregon and the fourth highest peak in the Cascade Range. Mount Hood is a stratovolcano in northwest Oregon located about fifty miles east of Portland and thirty-five miles south of the Columbia River. ![]()
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