Mount St. Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It lies 52 miles (83 km) northeast of Portland, Oregon, and 98 miles (158 km) south of Seattle. Mount St. Helens takes its English name from that of the British diplomat Alleyne Fitzherbert, 1st Baron St Helens, a friend of explorer George Vancouver who surveyed the area in the late 18th century. The volcano is part of the Cascade Volcanic Arc, a segment of the Pacific Ring of Fire.
The Cowlitz River is a river in the state of Washington in the United States, a tributary of the Columbia River. Its tributaries drain a large region including the slopes of Mount Rainier, Mount Adams, and Mount St. Helens.
On March 27, 1980, a series of volcanic explosions and pyroclastic flows began at Mount St. Helens in Skamania County, Washington, United States. A series of phreatic blasts occurred from the summit and escalated until a major explosive eruption took place on May 18, 1980, at 8:32 am. The eruption, which had a volcanic explosivity index of 5, was the first to occur in the contiguous United States since the much smaller 1915 eruption of Lassen Peak in California. It has often been considered the most disastrous volcanic eruption in U.S. history.
Spirit Lake is a lake in Skamania County, Washington, United States, located north of Mount St. Helens. It was a popular tourist destination for many years until Mount St. Helens erupted in 1980. Previously there had been six camps on the shore of Spirit Lake: Boy Scout, the Girl Scout Camp at Spirit Lake, two YMCA camps, Harmony Fall Lodge, and another for the general public. There were also several lodges accessible to visitors, including Spirit Lake Lodge and Mt. St. Helens Lodge. The latter was owned and operated by Harry R. Truman, a noted victim of the volcano's 1980 eruption.
The Lewis River is a tributary of the Columbia River, about 95 miles (153 km) long, in southwestern Washington in the United States. It drains part of the Cascade Range north of the Columbia River. The drainage basin of the Lewis River covers about 1,046 square miles (2,709 km2). The river's mean annual discharge is about 6,125 cubic feet per second (173.4 m3/s). Unlike nearby Lewis County and Fort Lewis the Lewis River was not named for Meriwether Lewis, but rather for A. Lee Lewis, an early colonizer who homesteaded near the mouth of the river.
The North Fork Toutle River is a tributary of the Toutle River in southwestern Washington in the United States. The river has its headwaters near Spirit Lake, on the north side of Mount St. Helens, and flows 39 miles (63 km) to the Toutle River, about 17 miles (27 km) upstream of its confluence with the Cowlitz River. The largest tributary is the Green River, which joins near the unincorporated town of Toutle.
State Route 504 is a state highway in southwestern Washington state in the United States. It travels 52 miles (84 km) along the North Fork Toutle River to the Mount St. Helens area, serving as the main access to the Mount St. Helens National Volcanic Monument. The highway begins at an interchange with Interstate 5 (I-5) and SR 411 in Castle Rock and terminates at the Johnston Ridge Observatory near Spirit Lake.
Silver Star Mountain is a recently uplifted ridge of older Western Cascades volcanic rock, underlain by a granitic pluton of similar Western Cascades age, located in the Cascade Range in the U.S. state of Washington. Consisting of late Eocene to Oligocene epoch rock, it lies within the Gifford Pinchot National Forest. Silver Star is composed of three lithologic units, including the large Silver Star Granodiorite unit.
The Toutle River is a 17.2-mile (27.7 km) tributary of the Cowlitz River in the U.S. state of Washington. It rises in two forks merging near Toutle below Mount St. Helens and joins the Cowlitz near Castle Rock, 20 miles (32 km) upstream of the larger river's confluence with the Columbia River.
The Cispus River is about 54 miles (87 km) long and flows into the Cowlitz River at Lake Scanewa in the Cascade Range of Washington. Its tributaries drain most of south-central and southeastern Lewis County, extreme northeast Skamania County, and some of western Yakima County.
The Touchet River is a 65-mile (105 km) tributary of the Walla Walla River in southeastern Washington in the United States. The Touchet River drains an area of about 752 square miles (1,950 km2) in Columbia County and Walla Walla County.
The Sediment Retention Structure is an earthen dam, 1,888 feet (575 m) long and 184 feet (56 m) high, on the North Fork Toutle River in the U.S. state of Washington. Completed by the United States Army Corps of Engineers in 1989, it is meant to prevent sediment from the 1980 eruption of Mount St. Helens from increasing flood risks along the Toutle and Cowlitz rivers.
State Route 503 (SR 503) is a 54.11-mile-long (87.08 km) state highway serving Clark and Cowlitz counties in the U.S. state of Washington. The highway travels north from a short concurrency with SR 500 in Orchards through Battle Ground, the eastern terminus of SR 502, and communities in rural Clark County before crossing the Lewis River on the Yale Bridge. SR 503 intersects its spur route and turns west to parallel the Lewis River downstream to Woodland, where the highway ends at an interchange with Interstate 5 (I-5). The highway was part of the Lewis River Road, signed as State Road 15, from 1909 until 1919. The current route of SR 503 was split between Secondary State Highway 1S (SSH 1) from Woodland to Battle Ground and SSH 1U from Battle Ground to Orchards in 1937, combined to form SR 503 during the 1964 highway renumbering. A spur route, established in 1991, travels northeast into the Gifford Pinchot National Forest along Yale Lake, serving the community of Cougar.
The Wind River is a tributary of the Columbia River, in the U.S. state of Washington. Its entire course of 30 miles (48 km) lies within Skamania County. Crusattes River is an old variant name.
The Tilton River is a tributary of the Cowlitz River, in the U.S. state of Washington. Named for the first territorial surveyor for Washington Territory James Tilton (surveyor), it flows for about 29 miles (47 km), entirely within Lewis County.
The Middle Fork Kings River is a 37.2-mile (59.9 km) tributary of the Kings River in Kings Canyon National Park, California, in the southern Sierra Nevada. Draining 318 square miles (820 km2) – almost all of it wilderness – the Middle Fork is one of the largest wholly undeveloped watersheds in the state, with no dams or paved roads within its basin. The entire length of the Middle Fork is designated a National Wild and Scenic River.
The Ohanapecosh River is a 16-mile (26 km) river in the U.S. state of Washington.
Kid Valley is an unincorporated community in Cowlitz County, Washington. Kid Valley is located east of the city of Castle Rock and along the North Fork Toutle River. Kid Valley is reached by traveling 17.8 miles (28.6 km) east of Castle Rock along Washington State Route 504, which is also known as the Spirit Lake Memorial Highway. The Kid Valley community is part of the Toutle Lake School District, a K-12 school district of about 600 students.
Coldwater Lake is a barrier lake on the border of Cowlitz County and Skamania County, Washington in the United States. The lake was created during the 1980 eruption of Mount St. Helens, which blocked its natural outlet, Coldwater Creek, with volcanic debris. It is one of several lakes in the area that were created or otherwise enlarged by the eruption.
Castle Creek is a tributary of the North Fork Toutle River on the flank of Mount St. Helens in Washington state. It rises about two miles (three kilometers) northwest of the crater rim and flows generally to the northwest. The outflow of Castle Lake joins the creek at the lake's north end after traveling a few hundred meters on the South Fork Castle Creek. It joins the North Fork Toutle River at 46.28302°N 122.29359°W, elevation 2,200 feet.
