Crater Lake ( Klamath: ''Giiwas'') is a

volcanic crater lake A volcanic crater lake is a lake in a crater that was formed by explosive activity or a collapse during a volcanic eruption. Formation Lakes in calderas fill large craters formed by the collapse of a volcano during an eruption. Lakes in maars ...

in south-central

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 ...

in the western United States. It is the main feature of

Crater Lake National Park Crater Lake National Park is an American national park located in southern Oregon. Established in 1902, Crater Lake is the fifth-oldest national park in the United States and the only national park in Oregon. The park encompasses the caldera of ...

and is famous for its deep blue color and water clarity. The lake partly fills a caldera that was formed around 7,700 (± 150) years ago by the collapse of the volcano

Mount Mazama Mount Mazama (''Giiwas'' in the Native American language Klamath) is a complex volcano in the state of Oregon, United States, in a segment of the Cascade Volcanic Arc and Cascade Range. Most of the mountain collapsed following a major erupt ...

. There are no rivers flowing into or out of the lake; the evaporation is compensated for by rain and snowfall at a rate such that the total amount of water is replaced every 250 years. With a depth of , the lake is the deepest in the United States. In the world, it ranks ninth for maximum depth, and third for mean (average) depth. Crater Lake features two small islands.

Wizard Island Wizard Island is a volcanic cinder cone which forms an island at the west end of Crater Lake in Crater Lake National Park, Oregon. The top of the island reaches above sea level, about above the average surface of the lake. The cone is capp ...

, located near the western shore of the lake, is a

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 ...

approximately 316 acres (128 ha) in size. Phantom Ship, a natural rock pillar, is located near the southern shore. Since 2002, one of Oregon's regular-issue license plate designs has featured Crater Lake and a one-time plate surcharge is used to support the operation of Crater Lake National Park. The commemorative Oregon State Quarter, which was released by the United States Mint in 2005, features an image of Crater Lake on its reverse. The lake and surrounding park areas offer many recreational activities including hiking, biking, snowshoeing, fishing, and cross-country skiing are available, and during the summer, campgrounds and lodges at Crater Lake are open to visitors.

Location

Crater Lake is in Klamath County, approximately northwest of the county seat of Klamath Falls, and about northeast of the city of Medford. A Native American connection with this area has been traced back to before the eruption of Mount Mazama. Archaeologists have found sandals and other artifacts buried under layers of ash, dust, and pumice that predate the eruption approximately 7,700 years ago. Crater Lake remains significant to the Klamath Tribes today. The Klamath name for the lake is "Giiwas." In June 1853, Isaac Skeeter, while on a mining trip, with John Wesley Hillman and another man were the first non-Native American explorers to report sighting the lake and he named it "Deep Blue Lake", inspired by Hillman's description of the lake. The lake was renamed at least three times, as Blue Lake, Lake Majesty, and finally Crater Lake. Crater Lake Panorama Spring 2016

Dimensions and depth

The lake is across, with a caldera rim ranging in elevation from and an average lake depth of . The lake's maximum depth has been measured at , which fluctuates slightly as the weather changes. On the basis of maximum depth, Crater Lake is the deepest lake in the United States, the second-deepest in North America (after

Great Slave Lake Great Slave Lake (french: Grand lac des Esclaves), known traditionally as Tıdeè in Tłı̨chǫ Yatıì (Dogrib), Tinde’e in Wıìlıìdeh Yatii / Tetsǫ́t’ıné Yatıé (Dogrib / Chipewyan), Tu Nedhé in Dëne Sųłıné Yatıé (Chi ...

in Canada), and the ninth-deepest lake in the world. Crater Lake is often cited as the seventh-deepest lake in the world, but this ranking excludes Lake Vostok in Antarctica, which is beneath about of ice, and the recent

depth sounding Depth sounding, often simply called sounding, is measuring the depth of a body of water. Data taken from soundings are used in bathymetry to make maps of the floor of a body of water, such as the seabed topography. Soundings were traditional ...

s of O'Higgins/San Martín Lake, which is along the border of

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

and

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the List of South American countries by area, second-largest ...

. When considering the mean, or average depth of lakes, Crater Lake becomes the deepest lake in the Western Hemisphere and the third-deepest in the world. Crater Lake Institute Director and

limnologist Limnology ( ; from Greek λίμνη, ''limne'', "lake" and λόγος, ''logos'', "knowledge") is the study of inland aquatic ecosystems. The study of limnology includes aspects of the biological, chemical, physical, and geological characteris ...

Owen Hoffman states that "Crater Lake is the deepest, when compared on the basis of average depth among lakes whose basins are entirely above

sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardis ...

. The average depths of Lakes

Baikal Lake Baikal (, russian: Oзеро Байкал, Ozero Baykal ); mn, Байгал нуур, Baigal nuur) is a rift lake in Russia. It is situated in southern Siberia, between the Federal subjects of Russia, federal subjects of Irkutsk Oblast, I ...

and

Tanganyika Tanganyika may refer to: Places * Tanganyika Territory (1916–1961), a former British territory which preceded the sovereign state * Tanganyika (1961–1964), a sovereign state, comprising the mainland part of present-day Tanzania * Tanzania Main ...

are deeper than Crater Lake; however, both have basins that extend below sea level."

Geology

Mount Mazama, part of 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, ...

volcanic arc, was built up mostly of

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predo ...

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 rhyo ...

, and

rhyodacite Rhyodacite is a volcanic rock intermediate in composition between dacite and rhyolite. It is the extrusive equivalent of those plutonic rocks that are intermediate in composition between monzogranite and granodiorite. Rhyodacites form from ra ...

over a period of at least 400,000 years. The caldera was created in a massive

volcanic eruption Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are oft ...

between 6,000 and 8,000 years ago that led to the subsidence of Mount Mazama. About of rhyodacite was erupted in this event. Since that time, all eruptions on Mazama have been confined to the caldera. Lava eruptions later created a central platform,

, Merriam Cone, and other, smaller volcanic features, including a rhyodacite dome that was eventually created atop the central platform. Sediments and

landslide Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated slope failures, mudflows, and debris flows. Landslides occur in a variety of environmen ...

debris also covered the caldera floor. Eventually, the caldera cooled, allowing rain and snow to accumulate and form a lake. Landslides from the caldera rim thereafter formed debris fans and

turbidite A turbidite is the geologic deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. Sequencing Turbidites wer ...

sediments on the lake bed.

Fumarole A fumarole (or fumerole) is a vent in the surface of the Earth or other rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcani ...

s and

hot spring A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circ ...

s remained common and active during this period. Also after some time, the slopes of the lake's caldera rim more or less stabilized, streams restored a radial drainage pattern on the mountain, and dense forests began to revegetate the barren landscape. It is estimated that about 720 years was required to fill the lake to its present depth of . Much of this occurred during a period when the prevailing climate was less moist than at present. Some

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

activity remains along the lake floor, suggesting that at some time in the future, Mazama may erupt once again.

Climate

Crater Lake features a

subalpine climate The subarctic climate (also called subpolar climate, or boreal climate) is a climate with long, cold (often very cold) winters, and short, warm to cool summers. It is found on large landmasses, often away from the moderating effects of an ocean, ge ...

, with the rare dry-summer type (

Köppen classification Köppen is a German surname. Notable people with the surname include: * Bernd Köppen (born 1951), German pianist and composer * Carl Köppen (1833-1907), German military advisor in Meiji era Japan * Edlef Köppen (1893–1939), German author an ...

''Dsc'') owing to its high elevation and – like all of Oregon – the strong summer influence of the

North Pacific High The North Pacific High is a semi-permanent, subtropical anticyclone located in the northeastern portion of the Pacific Ocean, located northeast of Hawaii and west of California. It is strongest during the northern hemisphere summer and shifts towa ...

. In the summer, the weather is mild and dry, but in the winter is cold and the powerful influence of the

Aleutian Low The Aleutian Low is a semi-permanent low-pressure system located near the Aleutian Islands in the Bering Sea during the Northern Hemisphere winter. It is a climatic feature centered near the Aleutian Islands measured based on mean sea-level press ...

allows for enormous snowfalls averaging per year and maximum snow cover averaging . This snow does not usually melt until mid-July, and allows for substantial glaciers on adjacent mountains. In the winter of 1949/1950 as much as of snow fell, while the less complete snow cover records show cover as high as occurred during another particularly unsettled winter in 1981/1982. The heaviest daily snowfall was , which occurred as recently as February 28, 1971; or more in one storm has occurred in both June and September. Hard frost is possible even into the summer, and the average window for freezing temperatures is August 20 through July 10, while for measurable (≥) snowfall, September 28 through June 11.

Ecology

Since the collapse of Mount Mazama due to a volcanic eruption formed Crater Lake, no fish inhabited the lake until William G. Steel decided to stock it in 1888 to allow for fishing. Regular stocking continued until 1941, when it was evident that the fish could maintain a stable population without outside interference. Six species of fish were originally stocked, but only two species have survived: kokanee salmon and

rainbow trout The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead (sometimes called "steelhead trout") is an anadromous (sea-run) form of the coast ...

, with the former being the most plentiful. Fishing in Crater Lake is promoted because the fish species are not indigenous to the lake. Crater Lake is also known for the " Old Man of the Lake", a full-sized tree which is now a log that has been bobbing vertically in the lake for over a century. The low temperature of the water has slowed the decomposition of the wood, hence its longevity. In 1987, scientists sent a

submersible A submersible is a small watercraft designed to operate underwater. The term "submersible" is often used to differentiate from other underwater vessels known as submarines, in that a submarine is a fully self-sufficient craft, capable of i ...

down to the depths of Crater Lake to obtain more information about the geology at the bottom of the lake, and inspect moss samples found in moss beds as deep as . Due to several unique factors, mainly that the lake has no inlets or

tributaries A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drain ...

, the waters of Crater Lake are some of the purest in the world because of the absence of pollutants. Clarity readings from a

Secchi disk The Secchi disk (or Secchi disc), as created in 1865 by Angelo Secchi, is a plain white, circular disk in diameter used to measure water transparency or turbidity in bodies of water. The disc is mounted on a pole or line, and lowered slowly down ...

have consistently been measured as being , which is very clear for any natural body of water. In 1997, scientists recorded a record clarity of . The lake has relatively high levels of dissolved salts, total

alkalinity Alkalinity (from ar, القلوي, al-qaly, lit=ashes of the saltwort) is the capacity of water to resist acidification. It should not be confused with basicity, which is an absolute measurement on the pH scale. Alkalinity is the strength ...

, and conductivity. The average pH has generally ranged between 7 and 8.

Sacred significance

The Klamath tribe of Native Americans, whose oral history describes their ancestors witnessing the collapse of Mount Mazama and the formation of Crater Lake, regard the lake as an "abode to the Great Spirit". Klamath oral history tells of a battle between the sky god Skell and the god of the underworld Llao (a prominent feature at Crater Lake is Llao Rock). Mount Mazama was destroyed in the battle, creating Crater Lake, called ''giiwas'' in the Klamath language. The Klamath people used Crater Lake in vision quests, which often involved climbing the caldera walls and other dangerous tasks. Those who were successful in such quests were often regarded as having more spiritual powers. The tribe still holds Crater Lake in high regard as a spiritual site.

Recreation

Located north of the city of Klamath Falls and northeast of Medford, Crater Lake can be reached from

U.S. Route 97 U.S. Route 97 (US 97) is a major north–south route of the United States Numbered Highway System in the Pacific Northwest region. It runs for approximately through the states of California, Oregon, and Washington, primarily serving i ...

on the east, on the southwest by Highway 62, and on the northwest by Highway 138. Crater Lake and the remnants of Mount Mazama can be seen from Rim Drive, a road that surrounds the caldera, which is the only part within the Crater Lake National Park where vehicles are permitted. The Garfield Peak Trail, which runs east from the Crater Lake Lodge, offers views from above the lake's surface, with Mount Shasta visible southward. Another trail runs for from Rim Drive's eastern edge to Mount Scott, which offers views of central and southern Oregon such as the Three Sisters located north of Mazama and

Mount Thielsen Mount Thielsen, or Big Cowhorn (Klamath: hisc’akwaleeʔas), is an extinct shield volcano in the Oregon High Cascades, near Mount Bailey. Because eruptive activity ceased 250,000 years ago, glaciers have heavily eroded the volcano's struc ...

, also to the north. The Cleetwood trail leads for down the northern flank of the caldera rim, eventually reaching Cleetwood Cove where boat trips run from late June or early July throughout the summer season to Wizard Island. Wizard Island can be climbed, offering views of Crater Lake. Swimming is permitted in Crater Lake, but the only legal and safe way to get to the shore is by following Cleetwood Cove trail and people can enter the water from there. Other activities include fishing and a 2-hour boat tour around the lake provided by a Park Ranger from

. As the region lies within a national park area, collecting rocks within the vicinity is prohibited unless a permit is obtained. The park's facilities lie at Rim Village, at the southern edge of the caldera. Lodging and camping facilities open during the summer season between May and October. No lodges, gas stations, or camping areas remain open from October through late May. Popular activities within Crater Lake National Park include

biking Cycling, also, when on a two-wheeled bicycle, called bicycling or biking, is the use of cycles for transport, recreation, exercise or sport. People engaged in cycling are referred to as "cyclists", "bicyclists", or "bikers". Apart from two ...

, fishing,

cross-country skiing Cross-country skiing is a form of skiing where skiers rely on their own locomotion to move across snow-covered terrain, rather than using ski lifts or other forms of assistance. Cross-country skiing is widely practiced as a sport and recreatio ...

, and

snowshoeing Snowshoes are specialized outdoor gear for walking over snow. Their large footprint spreads the user's weight out and allows them to travel largely on top of rather than through snow. Adjustable bindings attach them to appropriate winter footwe ...

Notes

References

* * ''Geology of National Parks: Fifth Edition'', Ann G. Harris, Esther Tuttle, Sherwood D. Tuttle, (Iowa, Kendall/Hunt Publishing; 1997) * * ''Oregon'', Moon Handbooks, Judy Jewell, W. C. McRae, (Avalon Travel, Berkeley; 2012, 9th edition)

External links

NPS: Crater Lake National Park

Crater Lake Data Clearinghouse

Oregon Institute of Technology: Crater Lake Digital Research Collection
{{Authority control Crater Lake National Park Lakes of Oregon Volcanic crater lakes Sacred lakes Religious places of the indigenous peoples of North America Cascade Volcanoes Subduction volcanoes Calderas of Oregon VEI-7 volcanoes Cascade Range Lakes of Klamath County, Oregon Volcanism of Oregon