Spiral Butte is a

cinder cone A cinder cone or scoria cone is a steep, volcanic cone, conical landform of loose pyroclastic rock, pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are forme ...

Yakima County Yakima County is a County (United States), county in the U.S. state of Washington (state), Washington. As of the 2020 United States census, 2020 census, its population was 256,728. The county seat and most populous city is Yakima, Washington, Ya ...

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

in the United States. The summit and most of the slopes are located within the

William O. Douglas Wilderness The William O. Douglas Wilderness is a designated wilderness in Central Washington. It includes located between the U.S. Route 12 and State Route 410 and is jointly administered by the Okanogan-Wenatchee National Forest and the Gifford P ...

of the

Okanogan–Wenatchee National Forest The Okanogan–Wenatchee National Forest is a U.S. National Forest located in Okanogan County, Washington, Okanogan County in north-central Washington (state), Washington, United States. The forest is bordered on the north by British Columbia, ...

between

White Pass White Pass, also known as the Dead Horse Trail (elevation ), is a mountain pass through the Boundary Ranges of the Coast Mountains on the border of the U.S. state of Alaska and the province of British Columbia, Canada. It leads from Skagway, Ala ...

and Rimrock Lake. Historically the mountain has also been referred to as Big Peak. The present name stems from its orientation with a lava flow extending north out of the cone before spiraling east and then south.

US 12 U.S. Route 12 or U.S. Highway 12 (US 12) is an east–west United States Numbered Highway, running from Aberdeen, Washington, to Detroit, Michigan, for almost . The highway has mostly been superseded by Interstate 90 (I-90) ...

runs along the southern slope of the butte.

Geography and Geology

Spiral Butte is located in the

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington (state), Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as m ...

in the

Pacific Northwest The Pacific Northwest (PNW; ) is a geographic region in Western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though no official boundary exists, the most common ...

. This mountain range exhibits several volcanoes which formed as the Juan de Fuca Plate located off the coast

subducted Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second plat ...

under the North American Plate. Volcanoes in the range extend from Northern California to British Columbia, including

Mount Rainier Mount Rainier ( ), also known as Tahoma, is a large active stratovolcano in the Cascade Range of the Pacific Northwest in the United States. The mountain is located in Mount Rainier National Park about south-southeast of Seattle. With an off ...

nearby as well as Mount St. Helens and

Mount Shasta Mount Shasta ( ; Shasta people, Shasta: ''Waka-nunee-Tuki-wuki''; Karuk language, Karuk: ''Úytaahkoo'') is a Volcano#Volcanic activity, potentially active stratovolcano at the southern end of the Cascade Range in Siskiyou County, California. A ...

. The cinder cone is modestly eroded and believed to be a satellite vent of

Goat Rocks Goat Rocks is an Volcano#Extinct, extinct stratovolcano in the Cascade Range, located between Mount Rainier and Mount Adams (Washington), Mount Adams in southern Washington (state), Washington, in the United States. Part of the Cascade Volcan ...

, an extinct and eroded

stratovolcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with ...

to the south. The volcanic field for Goat Rocks extends from the mountains themselves north to American Ridge near

Bumping Lake Bumping Lake is a lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on l ...

. Spiral Butte is surrounded by other Goat Rocks vents and lava flows, such as Tumac and Cramer Mountains to the north and Round Mountain to the south. Spiral Butte is separated from Round Mountain, which is in the

Goat Rocks Wilderness Goat Rocks Wilderness is a U.S. wilderness area in Washington, United States, comprising of Okanagan–Wenatchee National Forest and Gifford Pinchot National Forest on the crest of the Cascade Range south of U.S. Highway 12. Its central feat ...

by the canyon that Clear Creek flows through. Exposed lava from Spiral Butte is

hornblende Hornblende is a complex silicate minerals#Inosilicates, inosilicate series of minerals. It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. Hornblende minerals are common ...

dacite Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...

which has moderately high silica content. Other Cascade volcanoes also exhibit deposits of dacite. The exposed lava is less than 690,000 years old.

Recreation

Located within the William O. Douglas Wilderness of the Okanogan-Wenatchee National Forest, motorized vehicles are not allowed on Spiral Butte. A trail ascends the butte, connecting it to other backcountry trails in the region. The closest trailhead is the Sand Ridge Trailhead on US 12 near Dog Lake. Hiking directly from the Sand Ridge Trailhead is an round trip with of elevation gain. Being a cinder cone, the trail up the butte is sandy. Visitors climb through a

ponderosa pine ''Pinus ponderosa'', commonly known as the ponderosa pine, bull pine, blackjack pine, western yellow-pine, or filipinus pine, is a very large pine tree species of variable habitat native to mountainous regions of western North America. It is t ...

forest that transitions to

Douglas fir The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is the tallest tree in the Pinaceae family. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Or ...

and other similar trees with altitude. White Pass Ski Area, Rimrock Lake, and nearby volcanoes are visible from the summit.

References

{{reflist Goat Rocks Mountains of Yakima County, Washington Volcanoes of Washington (state) Cascade Volcanoes