The Three Sisters Wilderness is a

wilderness area Wilderness or wildlands (usually in the plural), are natural environments on Earth that have not been significantly modified by human activity or any nonurbanized land not under extensive agricultural cultivation. The term has traditionally re ...

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 and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...

, within the Willamette and

Deschutes National Forest The Deschutes National Forest is a United States National Forest located in parts of Deschutes, Klamath, Lake, and Jefferson counties in central Oregon. It comprises along the east side of the Cascade Range. In 1908, the Deschutes National F ...

s in

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

, United States. It comprises , making it the second largest wilderness area in Oregon, after the

Eagle Cap Wilderness Eagle Cap Wilderness is a wilderness area located in the Wallowa Mountains of northeastern Oregon (United States), within the Wallowa–Whitman National Forest.

. It was established by the

United States Congress The United States Congress is the legislature of the federal government of the United States. It is Bicameralism, bicameral, composed of a lower body, the United States House of Representatives, House of Representatives, and an upper body, ...

in 1964 and is named for the Three Sisters volcanoes. The wilderness boundary encloses the Three Sisters as well as

Broken Top Broken Top is a glacially eroded complex stratovolcano. It lies in the Cascade Volcanic Arc, part of the extensive Cascade Range in the U.S. state of Oregon. Located southeast of the Three Sisters peaks, the volcano, residing within the Three ...

, which is southeast of South Sister.Three Sisters Wilderness
- Wilderness.net Three Sisters was designated as a

UNESCO The United Nations Educational, Scientific and Cultural Organization is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) aimed at promoting world peace and security through international coope ...

Biosphere Reserve under the

Man and the Biosphere Programme Man and the Biosphere Programme (MAB) is an intergovernmental scientific program, launched in 1971 by UNESCO, that aims to establish a scientific basis for the improvement of relationships between people and their environments. MAB's work engag ...

in 1976, and was one of 17 reserves in the United States withdrawn from the programme in June 2017.

Oregon Route 242 Oregon Route 242, known as a portion of the McKenzie Highway, is an Oregon state highway that runs from Belknap Springs, Oregon through McKenzie Pass in the Oregon Cascades, to Sisters, Oregon, in the United States. The McKenzie Highway was ad ...

separates the Three Sisters Wilderness from the Mount Washington Wilderness to the north, while the Waldo Lake Wilderness shares the southern boundary. The three peaks were known by pioneers as Faith, Hope and Charity. Nearby landmarks include The Husband, The Wife, and the Little Brother.

Geology

Many types of landforms make up the wilderness area, but the most common are

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plat ...

features, the most notable being the Cascades which are

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

es having formed around 1.6 million years ago. Numerous

cinder cone A cinder cone (or scoria cone) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruption ...

s have formed on their flanks as well as many

lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

s that contain hundreds of

lava tube A lava tube, or pyroduct, is a natural conduit formed by flowing lava from a volcanic vent that moves beneath the hardened surface of a lava flow. If lava in the tube empties, it will leave a cave. Formation A lava tube is a type of lava ...

Topography

The Three Sisters Wilderness ranges in elevation from . The Three Sisters—North Sister at , Middle Sister at , and South Sister at — are found in the eastern portion of the Wilderness. Including

—just to the south at — there are 14 glaciers offering one of the best examples of the effects of

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate bet ...

in the Pacific Northwest.

Collier Glacier Collier Glacier is in the U.S. state of Oregon. The glacier is situated in the Cascade Range at an elevation generally above . Collier Glacier is on the west slopes of North Sister, an extinct shield volcano. Since its last maximum extent during ...

, between North and Middle Sister, is the largest

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such a ...

in Oregon. The headwaters of the

Wild and Scenic The National Wild and Scenic Rivers System was created by the Wild and Scenic Rivers Act of 1968 (Public Law 90-542), enacted by the U.S. Congress to preserve certain rivers with outstanding natural, cultural, and recreational values in a free- ...

Whychus Creek (formerly Squaw Creek) emerge in the Wilderness.

Vegetation

Forest cover in the Three Sisters Wilderness includes

Douglas fir The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three v ...

Pacific silver fir ''Abies amabilis'', commonly known as the Pacific silver fir, is a fir native to the Pacific Northwest of North America, occurring in the Pacific Coast Ranges and the Cascade Range. It is also commonly referred to as the white fir, red fir, love ...

subalpine fir ''Abies lasiocarpa'', the subalpine fir or Rocky Mountain fir, is a western North American fir tree. Description ''Abies lasiocarpa'' is a medium-sized evergreen conifer with a very narrow conic crown, growing to tall, exceptionally , with a t ...

mountain hemlock ''Tsuga mertensiana'', known as mountain hemlock, is a species of hemlock native to the west coast of North America, found between Southcentral Alaska and south-central California. Description ''Tsuga mertensiana'' is a large evergreen conifer ...

western hemlock ''Tsuga heterophylla'', the western hemlock or western hemlock-spruce, is a species of hemlock native to the west coast of North America, with its northwestern limit on the Kenai Peninsula, Alaska, and its southeastern limit in northern Sonoma ...

lodgepole pine ''Pinus contorta'', with the common names lodgepole pine and shore pine, and also known as twisted pine, and contorta pine, is a common tree in western North America. It is common near the ocean shore and in dry montane forests to the subalpin ...

and

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 the ...

. A large area of the Wilderness above timberline contains

alpine Alpine may refer to any mountainous region. It may also refer to: Places Europe * Alps, a European mountain range ** Alpine states, which overlap with the European range Australia * Alpine, New South Wales, a Northern Village * Alpine National P ...

meadows.Three Sisters Wilderness
- Willamette National Forest

Recreation

Popular recreational activities in the Three Sisters Wilderness include camping, hiking, climbing and fishing. South Sister and Middle Sister are not technically difficult climbs, but summiting North Sister requires technical expertise and equipment. More than of trails cross the wilderness, including of the

Pacific Crest Trail The Pacific Crest Trail (PCT), officially designated as the Pacific Crest National Scenic Trail, is a long-distance hiking and equestrian trail closely aligned with the highest portion of the Cascade and Sierra Nevada mountain ranges, which lie ...

. The

French Pete Trail The French Pete Trail is a hiking trail in the valley of French Pete Creek in the Three Sisters Wilderness of western Oregon. The trail passes through low-elevation old-growth forest that was a nationwide political issue in the 1960s and 197 ...

and its surrounding old-growth forest, a nationwide political issue in the 1970s, are located on the western edge of the wilderness near

Cougar Reservoir Cougar Reservoir (also known as Cougar Lake) is a reservoir on the South Fork McKenzie River in the U.S. state of Oregon. It is in Lane County, east of Eugene and about south of the community of Rainbow in the Willamette National Forest. In ...

References

External links