Crater Lake is a crater lake in south-central Oregon in the western United States. It is the main feature of Crater Lake National Park and is famous for its deep blue color and water clarity; the lake fills a nearly 2,148-foot -deep caldera, formed around 7,700 years ago by the collapse of the volcano Mount Mazama. There are no rivers flowing out of the lake. With a depth of 1,949 feet, the lake is the deepest in the United States. In the world, it ranks ninth for maximum depth, third for mean depth. Crater Lake features two small islands. Wizard Island, located near the western shore of the lake, is a cinder cone 316 acres in size. Phantom Ship, a natural rock pillar, is located near the southern shore. In 2002, one of the state's regular-issue license plate designs has featured Crater Lake; the commemorative Oregon State Quarter, released by the United States Mint in 2005, features an image of Crater Lake on its reverse. Crater Lake is in Klamath County 60 miles northwest of the county seat of Klamath Falls, about 80 miles northeast of the city of Medford.
In June 1853, John Wesley Hillman became the first non-Native American explorer to report sighting the lake he named the "Deep Blue Lake." The lake was renamed at least three times, as Blue Lake, Lake Majesty, Crater Lake. The lake is 5 by 6 miles across, with a caldera rim ranging in elevation from 7,000 to 8,000 feet and an average lake depth of 1,148 feet; the lake's maximum depth has been measured at 1,949 feet, which fluctuates 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, the ninth-deepest lake in the world. Crater Lake is cited as the seventh-deepest lake in the world, but this ranking excludes Lake Vostok in Antarctica, beneath about 13,000 feet of ice, the recent depth soundings of O'Higgins/San Martín Lake, along the border of Chile and Argentina; 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 Owen Hoffman states "Crater Lake is the deepest, when compared on the basis of average depth among lakes whose basins are above sea level. The average depths of Lakes Baikal and Tanganyika are deeper than Crater Lake. Mount Mazama, part of the Cascade Range volcanic arc, was built up of andesite and rhyodacite over a period of at least 400,000 years; the caldera was created in a massive volcanic eruption between 6,000 and 8,000 years ago that led to the subsidence of Mount Mazama. About 50 cubic kilometers of rhyodacite was erupted in this event. Since that time, all eruptions on Mazama have been confined to the caldera. Lava eruptions created a central platform, Wizard Island, Merriam Cone, other, smaller volcanic features, including a rhyodacite dome, created atop the central platform. Sediments and landslide debris covered the caldera floor; the caldera cooled, allowing rain and snow to accumulate and form a lake. Landslides from the caldera rim thereafter formed debris fans and turbidite sediments on the lake bed.
Fumaroles and hot springs remained active during this period. After some time, the slopes of the lake's caldera rim more or less stabilized, streams restored a radial drainage pattern on the mountain, 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 594 metres. Much of this occurred during a period; some hydrothermal activity remains along the lake floor, suggesting that at some time in the future, Mazama may erupt once again. In 2008, scientists submerged a robot into the lake to collect more geological information to compare to the data obtained in the 1980s; the scientists hypothesized that the moss was about 6,000 years old by measuring the age of pollen that blew into the lake and mixed with the sediment. Crater Lake features a subalpine climate, with the rare dry-summer type owing to its high elevation and – like all of Oregon – the strong summer influence of the North Pacific High. In the summer, the weather is mild and dry, but in the winter is cold and the powerful influence of the Aleutian Low allows for enormous snowfalls averaging 505 inches per year and maximum snow cover averaging 139 inches or 3.53 meters.
This snow does not melt until mid-July, allows for substantial glaciers on adjacent mountains. In the winter of 1949/1950 as much as 885.1 inches of snow fell, while the less complete snow cover records show cover as high as 192 inches or 4.88 meters occurred during another unsettled winter in 1981/1982. The heaviest daily snowfall was 37.0 inches, which occurred as as February 28, 1971. Hard frost is possible into the summer, the average window for freezing temperatures is August 19 through July 7, while for measurable snowfall, October 1 through June 15. Surface temperatures of the lake range between 33 degrees Fahrenheit and 66 degrees Fahrenheit. In the summer, the lake temperature falls between 50 degrees Fahre
Fire lookout tower
A fire lookout tower, fire tower or lookout tower, provides housing and protection for a person known as a "fire lookout" whose duty it is to search for wildfires in the wilderness. The fire lookout tower is a small building located on the summit of a mountain or other high vantage point, in order to maximize the viewing distance and range, known as view shed. From this vantage point the fire lookout can see smoke that may develop, determine the location by using a device known as an Osborne Fire Finder, call fire suppression personnel to the fire. Lookouts report weather changes and plot the location of lightning strikes during storms; the location of the strike is monitored for a period of days after in case of ignition. The typical fire lookout tower consists of a small room, known as a cab located atop a large steel, or wooden tower; the tops of tall trees have been used to mount permanent platforms. Sometimes natural rock may be used to create a lower platform. In cases where the terrain makes a tower unnecessary, the structure is known as a ground cab.
Ground cabs are called towers if they don't sit on a tower. Towers gained popularity in the early 1900s, fires were reported using telephones, carrier pigeons, heliographs. Although many fire lookout towers have fallen into disrepair as a result of neglect and declining budgets, some fire service personnel have made an effort to preserve older fire towers, arguing that a good set of human eyes watching the forest for wildfire can be an effective and cheap fire safety measure; the history of fire lookout towers predates the United States Forest Service, founded in 1905. Many townships, private lumber companies, State Forestry organizations operated fire lookout towers on their own accord; the Great Fire of 1910 known as the Big Blowup, burned 3,000,000 acres through the states of Washington and Montana. It is still arguably the largest forest fire in recorded history; the smoke from this fire drifted across the entire country to Washington D. C. — both physically and politically — and it challenged the five-year-old Forest Service to address new policies regarding fire suppression, the fire did much to create the fire rules and policies that we have today.
One of the rules as a result of the 1910 fire stated "all fires must be extinguished by 10 a.m. the following morning". To prevent and suppress fires, the U. S. Forest Service made another rule that townships and States would bear the cost of contracting fire suppression services, because at the time there was not the large Forest Service Fire Department that exists today; as a result of the above rules, early fire detection and suppression became a priority. Towers began to be built across the country. While earlier lookouts used tall trees and high peaks with tents for shelters, by 1911 permanent cabins and cupolas were being constructed on mountaintops. Beginning in 1910, the New Hampshire Timberlands Owners Association, a fire protection group, was formed and soon after, similar organizations were set up in Maine and Vermont. A leader of these efforts, W. R. Brown, an officer of the Brown Company which owned over 400,000 acres of timberland, set up a series of effective forest-fire lookout towers the first in the nation, by 1917 helped establish a forest-fire insurance company.
In 1933, during the Great Depression, President Franklin Delano Roosevelt formed the Civilian Conservation Corps, consisting of young men and veterans of World War I. It was during this time that the CCC set about building fire lookout towers, access roads to those towers; the U. S. Forest Service took great advantage of the CCC workforce and initiated a massive program of construction projects, including fire lookout towers. In California alone, some 250 lookout towers and cabs were built by CCC workers between 1933 and 1942; the heyday of fire lookout towers was from 1930 through 1950. During World War II, the Aircraft Warning Service was established, operating from mid-1941 to mid-1944. Fire lookouts were assigned additional duty as Enemy Aircraft Spotters on the West Coast of the United States. From the 1960s through the 1990s the towers took a back seat to new technology and improvements in radios; the promise of space satellite fire detection and modern cell phones tried to compete with the remaining fire lookout towers, but in several environments, the technology failed.
Fires detected from space are too large to make accurate assessments for control. Cell phones in wilderness areas still suffer from lack of signal. Today, some fire lookout towers remain in service, because having human eyes being able to detect smoke and call in the fire report allows fire management officials to decide early how the fire is to be managed; the more modern policy is to "manage fire", not to suppress it. Fire lookout towers provide a reduction in time of fire detection to time of fire management assessment. Idaho had the most known lookout sites. Kansas is the only U. S. state. A number of fire lookout tower stations located in New York State near the Adirondack Forest Preserve and Catskill Park, have been listed on the National Register of Historic Places, they include Arab Mountain Fire Observation Station, Azure Mountain Fire Observation Station, Balsam Lake Mountain Fire Observation Station, Blue Mountain Fire Observation Station, Hadley Mountain Fire Observation Station, Kane Mountain Fire Observation Station, Loon Lake Mountain Fire Observation Station, Mount Tremper Fire Observation Station, Poke-O-Moonshine Mountain Fire Observation Station, Red Hill Fire Observation Station, St. Regis Mountain Fire
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 6,933 feet above sea level, about 755 feet above the average surface of the lake; the cone is 100 feet deep. The crater was named the "Witches Cauldron" by William Gladstone Steel in 1885, who gave Wizard Island its name at the same time; the land area of the island is 315.85 acres. Wizard Island was created after Mount Mazama, a large complex volcano, erupted violently 7,700 years ago, forming its caldera which now contains Crater Lake. Following the cataclysmic caldera-forming eruption, which left a hole about 4,000 feet deep where the mountain had once stood, a series of smaller eruptions over the next several hundred years formed several cinder cones on the caldera floor; the highest of these cones, the only one to rise above the current lake level, is Wizard Island, which rises over 2,700 feet above the lowest point on the caldera floor and the deepest point in the lake.
Another large cinder cone, Merriam Cone, is located in the northeast part of the lake. Although Merriam Cone rises about 1,400 feet above the caldera floor, its summit is still 505 feet below the average lake level, its surface features and lack of a crater indicate. Current public access to Wizard Island is available only during the summer months when boat tours on Crater Lake are in operation; the tours depart from Cleetwood Cove at the north end of the lake, circle the lake in the counterclockwise direction, stopping at a dock at Governors Bay on the south side of Wizard Island. Passengers on boat trips early in the day may choose to disembark on the island, but must be prepared to spend the entire day on the island if subsequent boats are too full to take on additional passengers; those on late afternoon boat trips are not permitted to disembark. A final boat is dispatched at the end of each day to pick up any stragglers since overnight camping is not permitted on the island. Two hiking trails are available on Wizard Island, one of which switchbacks up the flanks of the cone and circles the crater on top while the other trail meanders from the dock towards the western end of the island.
USGS Crater Lake Data Clearinghouse USGS Crater Lake Bathymetry Images USGS: Crater Lake, OR: Wizard Island Perspective View USGS: Crater Lake, OR: Merriam Cone Perspective View Crater Lake National Park Crater Lake Boat Tours
A glacier is a persistent body of dense ice, moving under its own weight. Glaciers deform and flow due to stresses induced by their weight, creating crevasses and other distinguishing features, they abrade rock and debris from their substrate to create landforms such as cirques and moraines. Glaciers form only on land and are distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets in the polar regions, but glaciers may be found in mountain ranges on every continent including Oceania's high-latitude oceanic island countries such as New Zealand and Papua New Guinea. Between 35°N and 35°S, glaciers occur only in the Himalayas, Rocky Mountains, a few high mountains in East Africa, New Guinea and on Zard Kuh in Iran. Glaciers cover about 10 percent of Earth's land surface. Continental glaciers cover nearly 13 million km2 or about 98 percent of Antarctica's 13.2 million km2, with an average thickness of 2,100 m.
Greenland and Patagonia have huge expanses of continental glaciers. Glacial ice is the largest reservoir of fresh water on Earth. Many glaciers from temperate and seasonal polar climates store water as ice during the colder seasons and release it in the form of meltwater as warmer summer temperatures cause the glacier to melt, creating a water source, important for plants and human uses when other sources may be scant. Within high-altitude and Antarctic environments, the seasonal temperature difference is not sufficient to release meltwater. Since glacial mass is affected by long-term climatic changes, e.g. precipitation, mean temperature, cloud cover, glacial mass changes are considered among the most sensitive indicators of climate change and are a major source of variations in sea level. A large piece of compressed ice, or a glacier, appears blue, as large quantities of water appear blue; this is. The other reason for the blue color of glaciers is the lack of air bubbles. Air bubbles, which give a white color to ice, are squeezed out by pressure increasing the density of the created ice.
The word glacier is a loanword from French and goes back, via Franco-Provençal, to the Vulgar Latin glaciārium, derived from the Late Latin glacia, Latin glaciēs, meaning "ice". The processes and features caused by or related to glaciers are referred to as glacial; the process of glacier establishment and flow is called glaciation. The corresponding area of study is called glaciology. Glaciers are important components of the global cryosphere. Glaciers are categorized by their morphology, thermal characteristics, behavior. Cirque glaciers form on the slopes of mountains. A glacier that fills a valley is called a valley glacier, or alternatively an alpine glacier or mountain glacier. A large body of glacial ice astride a mountain, mountain range, or volcano is termed an ice cap or ice field. Ice caps have an area less than 50,000 km2 by definition. Glacial bodies larger than 50,000 km2 are called continental glaciers. Several kilometers deep, they obscure the underlying topography. Only nunataks protrude from their surfaces.
The only extant ice sheets are the two that cover most of Greenland. They contain vast quantities of fresh water, enough that if both melted, global sea levels would rise by over 70 m. Portions of an ice sheet or cap that extend into water are called ice shelves. Narrow, fast-moving sections of an ice sheet are called ice streams. In Antarctica, many ice streams drain into large ice shelves; some drain directly into the sea with an ice tongue, like Mertz Glacier. Tidewater glaciers are glaciers that terminate in the sea, including most glaciers flowing from Greenland, Antarctica and Ellesmere Islands in Canada, Southeast Alaska, the Northern and Southern Patagonian Ice Fields; as the ice reaches the sea, pieces break off, or calve. Most tidewater glaciers calve above sea level, which results in a tremendous impact as the iceberg strikes the water. Tidewater glaciers undergo centuries-long cycles of advance and retreat that are much less affected by the climate change than those of other glaciers.
Thermally, a temperate glacier is at melting point throughout the year, from its surface to its base. The ice of a polar glacier is always below the freezing point from the surface to its base, although the surface snowpack may experience seasonal melting. A sub-polar glacier includes both temperate and polar ice, depending on depth beneath the surface and position along the length of the glacier. In a similar way, the thermal regime of a glacier is described by its basal temperature. A cold-based glacier is below freezing at the ice-ground interface, is thus frozen to the underlying substrate. A warm-based glacier is above or at freezing at the interface, is able to slide at this contact; this contrast is thought to a large extent to govern the ability of a glacier to erode its bed, as sliding ice promotes plucking at rock from the surface below. Glaciers which are cold-based and warm-based are known as polythermal. Glaciers form where the accumulation of ice exceeds ablation. A glacier originates from a landform called'cirque' – a armchair-shaped geological feature (such as a depressio
A trail is a path, track or unpaved lane or road. In the United Kingdom and the Republic of Ireland path or footpath is the preferred term for a walking trail; the term is applied, in North America, to routes along rivers, sometimes to highways. In the US, the term was used for a route into or through wild territory used by emigrants. In the USA "trace" is a synonym for trail, as in Natchez Trace; some trails are single use and can only be used for walking, horse riding and cross-country skiing. There are unpaved trails used by dirt bikes and other off-road vehicles and in some places, like the Alps, trails are used for moving cattle and other livestock. In Australia, the term track can be used interchangeably with trail, can refer to anything from a dirt road to an unpaved pedestrian path. In New Zealand, the terms track or walkway are used exclusively except in reference to cross-country skiing: "walkways vary enormously in nature, from short urban strolls, to moderate coastal locations, to challenging tramps in the high country ".
Walkway is used in St. John's, Canada, where the "Grand Concourse", is an integrated walkway system. In the United Kingdom, the term trail is in common usage. Longer distance walking routes, government-promoted long distance paths, collectively known as National Trails, are frequently called ways; the term footpath is preferred for pedestrian routes, including long distance trails, is used for urban paths and sometimes in place of pavement. Track is used for wider paths used for hiking; the terms bridleway, restricted byway are all recognised legal terms and to a greater or lesser extent in general usage. The increased popularity of mountain biking has led to a proliferation of mountain bike trails in many countries; these will be grouped to form larger complexes, known as trail centers. In the early years of the 20th century, the term auto trail was used for a marked highway route, trail is now used to designate routes, including highway routes, designated for tourist interest like the Cabot Trail, Nova Scotia and the Quilt Trails in the US.
The term trail has been used by developers and urban planners for a variety of modern paved roads and boulevards, in these countries, some highways continue to be called a trail, such as the Susquehanna Trail in Pennsylvania, a designation that varies from a two-lane road to a four-lane freeway. A unusual use of the term is in the Canadian province of Alberta, which has multi-lane freeways called trails. Trail segregation, the practice of designating certain trails as having a specific preferred or exclusive use, is common and diverse. For example, bike trails are used not only on roads open to motor vehicles, but in trail systems open to other trail users; some trails are segregated for use by both equestrians and mountain bikes, or by equestrians only, or by mountain bikes only. Designated "wilderness area" trails may be segregated for non-wheeled use. Trail segregation for a particular use is accompanied by prohibitions against that use on other trails within the trail system. Trail segregation may be supported by signage, trail design and construction, by separation between parallel treads.
Separation may be achieved by "natural" barriers including distance, banking and vegetation, by "artificial" barriers including fencing and walls. Bicycle trails encompass a wide variety of trail types, including shared-use paths used for commuting, off-road cross country trails and downhill mountain bike trails; the number of off-road cycle trails has increased along with the popularity of mountain bikes. Off-road bicycle trails are function-specific and most waymarked along their route, they may form part of larger complexes, known as trail centres. Off-road trails incorporate a mix of challenging terrain, smooth fireroads, paved paths. Trails with an easy or moderate technical complexity are deemed cross-country trails, while trails difficult to experienced riders are more dubbed all-mountain, freeride, or downhill. Downhilling is popular at ski resorts such as Mammoth Mountain in California or Whistler Blackcomb in British Columbia, where ski lifts are used to get bikes and riders to the top of the mountain.
EuroVelo bicycle routes are a network of long-distance cycling routes criss-crossing Europe in various stages of completion, more than 45,000 km was in place by 2013. It is envisaged that the network will be complete by 2020 and when finished, the EuroVelo network's total length will exceed 70,000 km. EuroVelo is a project of the European Cyclists' Federation. EuroVelo routes can be used for bicycle touring across the continent, as well as by local people making short journeys; the routes are made of both existing national bike routes, such as the Dutch LF-Routes, the German D-Routes, the British National Cycle Network, existing general purpose roads, together with new stretches of cycle routes to connect them. Off-road cycling can cause soil erosion and habitat destruction if not carried out on established trails; this is so when trails are wet, overall though, cycling may have only as mu
McKenzie Pass, elevation 5,325 feet, is a mountain pass in the Cascade Range in central Oregon in the United States. It is located at the border of Linn and Deschutes counties 25 miles as the crow flies northwest of Bend, between the Three Sisters to the south and Mount Washington to the north. Oregon Route 242 goes over the pass. At the summit of the pass, Oregon Route 242 crosses a 65-square-mile lava flow just west of Sisters. Surrounded by lava, the Dee Wright Observatory was constructed in 1935 by Civilian Conservation Corps workers and named after their foreman. Visitors climb to the observatory to view the Cascade peaks visible from McKenzie Pass. Near the summit is Clear Lake, a renowned location for fresh-water diving. Highway 242 is not recommended for large trucks, trailers or motor homes due to numerous tight switchbacks; the pass is closed from November to July due to snow. The pass is named for Donald McKenzie, a Scottish Canadian fur trader who explored parts of the Pacific Northwest for the Pacific Fur Company in the early 19th century.
McKenzie Bridge, Oregon McKenzie River Gerald W. Williams, McKenzie Pass at The Oregon Encyclopedia
This article is for the volcanic arc. For the namesake mountain range see Cascade Range; the Cascade Volcanoes are a number of volcanoes in a volcanic arc in western North America, extending from southwestern British Columbia through Washington and Oregon to Northern California, a distance of well over 700 miles. The arc formed due to subduction along the Cascadia subduction zone. Although taking its name from the Cascade Range, this term is a geologic grouping rather than a geographic one, the Cascade Volcanoes extend north into the Coast Mountains, past the Fraser River, the northward limit of the Cascade Range proper; some of the major cities along the length of the arc include Portland and Vancouver, the population in the region exceeds 10 million. All could be affected by volcanic activity and great subduction-zone earthquakes along the arc; because the population of the Pacific Northwest is increasing, the Cascade volcanoes are some of the most dangerous, due to their eruptive history and potential for future eruptions, because they are underlain by weak, hydrothermally altered volcanic rocks that are susceptible to failure.
Mount Rainier is one of the Decade Volcanoes identified by the International Association of Volcanology and Chemistry of the Earth's Interior as being worthy of particular study, due to the danger it poses to Seattle and Tacoma. Many large, long-runout landslides originating on Cascade volcanoes have engulfed valleys tens of kilometers from their sources, some of the areas affected now support large populations; the Cascade Volcanoes are part of the Pacific Ring of Fire, the ring of volcanoes and associated mountains around the Pacific Ocean. The Cascade Volcanoes have erupted several times in recorded history. Two most recent were Lassen Peak in 1914 to 1921 and a major eruption of Mount St. Helens in 1980, it is the site of Canada's most recent major eruption about 2,350 years ago at the Mount Meager massif. The Cascade Arc includes nearly 20 major volcanoes, among a total of over 4,000 separate volcanic vents including numerous stratovolcanoes, shield volcanoes, lava domes, cinder cones, along with a few isolated examples of rarer volcanic forms such as tuyas.
Volcanism in the arc began about 37 million years ago. Twelve volcanoes in the arc are over 10,000 feet in elevation, the two highest, Mount Rainier and Mount Shasta, exceed 14,000 feet. By volume, the two largest Cascade volcanoes are the broad shields of Medicine Lake Volcano and Newberry Volcano, which are about 145 cubic miles and 108 cubic miles respectively. Glacier Peak is the only Cascade volcano, made of dacite. Over the last 37 million years, the Cascade Arc has been erupting a chain of volcanoes along the Pacific Northwest. Several of the volcanoes in the arc are active; the volcanoes of the Cascade Arc share some general characteristics, but each has its own unique geological traits and history. Lassen Peak in California, which last erupted in 1917, is the southernmost active volcano in the arc, while the Mount Meager massif in British Columbia, which erupted about 2,350 years ago, is considered the northernmost member of the arc. A few isolated volcanic centers northwest of the Mount Meager massif such as the Silverthrone Caldera, a circular 20 km wide dissected caldera complex, may be the product of Cascadia subduction because the igneous rocks andesite, basaltic andesite and rhyolite can be found at these volcanoes as they are elsewhere along the subduction zone.
At issue are the current estimates of plate configuration and rate of subduction, but based on the chemistry of these volcanoes, they are subduction related and therefore part of the Cascade Volcanic Arc. The Cascade Volcanic Arc appears to be segmented. Lavas representing the earliest stage in the development of the Cascade Volcanic Arc crop out south of the North Cascades proper, where uplift of the Cascade Range has been less, a thicker blanket of Cascade Arc volcanic rocks has been preserved. In the North Cascades, geologists have not yet identified with any certainty any volcanic rocks as old as 35 million years, but remnants of the ancient arc's internal plumbing system persist in the form of plutons, which are the crystallized magma chambers that once fed the early Cascade volcanoes; the greatest mass of exposed Cascade Arc plumbing is the Chilliwack batholith, which makes up much of the northern part of North Cascades National Park and adjacent parts of British Columbia beyond. Individual plutons range in age from about 35 million years old to 2.5 million years old.
The older rocks invaded by all this magma were affected by the heat. Around the plutons of the batholith, the older rocks recrystallized; this contact metamorphism produced a fine mesh of interlocking crystals in the old rocks strengthening them and making them more resistant to erosion. Where the recrystallization was intense, the rocks took on a new appearance dark and hard. Many rugged peaks in the North Cascades owe their prominence to this baking; the rocks holding up many such North Cascade giants, as Mount Shuksan, Mount Redoubt, Mount Challenger, Mount Hozomeen, are all recrystallized by plutons of the nearby and underlying Chilliwack batholith. The Garibaldi Volcanic Belt is the northern extension of the Cascade Arc. Volcanoes within the volcanic belt are stratovolcanoes along with the