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112-669: The Cascades are part of the Pacific Ocean 's Ring of Fire , the ring of volcanoes and associated mountains around the Pacific Ocean. All of the eruptions in the contiguous United States over the last 200 years have been from the Cascade Volcanoes . The two most recent were Lassen Peak from 1914 to 1921 and a major eruption of Mount St. Helens in 1980 . Minor eruptions of Mount St. Helens have also occurred since, most recently from 2004 to 2008. The Cascade Range

224-488: A chain of volcanoes (the Cascade Volcanic Arc) above the subduction zone. Soil conditions for farming are generally good, especially downwind of volcanoes . This is largely because volcanic rocks are often rich in potassium -bearing minerals such as orthoclase , and erode relatively easily. Volcanic debris, especially lahars , also helps to spread mineral-rich volcanic material, and the storage of water in

336-607: A few wolf packs returning from Canada live in the Cascades. Fewer than 50 grizzly bears reside in the Cascades of Canada and Washington. Pacific Ocean Main five oceans division: Further subdivision: The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions . It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica ) in

448-538: A few strikingly large volcanoes, like Mount Hood and Mount St. Helens, that dominate the landscape. The Cascade volcanoes define the Pacific Northwest section of the Ring of Fire , an array of volcanoes that rim the Pacific Ocean. The Ring of Fire is also known for its frequent earthquakes. The volcanoes and earthquakes arise from a common source: subduction , where the dense Juan de Fuca Plate plunges beneath

560-620: A fur trader with the North West Company , seeking a viable route across the mountains, explored and crossed the northern Cascades between Fort Okanogan and Puget Sound. His report of the journey is vague about the route taken. He followed the lower Methow River into the mountains. He might have used Cascade Pass to reach the Skagit River . Ross was the first European-American to explore the Methow River area and likely

672-461: A minor variety : The species name mertensiana refers to Karl Heinrich Mertens (1796–1830), a German botanist who collected the first specimens as a member of a Russian expedition in 1826–1829. The distribution of T. mertensiana stretches from Kenai Peninsula , Alaska , to northern Tulare County , California . Its range fairly closely matches that of T. heterophylla (western hemlock), found less than 100 kilometers (62 miles) from

784-535: A narrow green midrib between the bands; they differ from those of any other species of hemlock in also having stomata on the upper surface, and are arranged spirally all around the shoot. The cones are small (but much longer than those of any other species of hemlock), pendulous, cylindrical, 3 to 8 cm (1 to 3 in) long and 8 to 10 mm ( 5 ⁄ 16 to 3 ⁄ 8  in) broad when closed, opening to 12 to 35 mm ( 1 ⁄ 2 to 1 + 3 ⁄ 8  in) broad, superficially somewhat like

896-709: A short, warm-to-cool growing season and moderate to high precipitation. Best development of mountain hemlock is on loose, coarse-textured, well-drained soils with adequate moisture, and in British Columbia, on thick and very acidic organic matter and decayed wood. Adequate soil moisture appears to be especially important in California and Montana, where summer drought is most pronounced. Mountain hemlock will grow on most landforms , but individuals typically develop best in mixed stands of forest on sheltered slopes or in draws. From southern British Columbia south,

1008-478: A small spruce cone. They have thin, flexible scales 8 to 18 mm ( 5 ⁄ 16 to 11 ⁄ 16  in) long. The immature cones are dark purple (rarely green), maturing red–brown 5 to 7 months after pollination. The seeds are red–brown, 2 to 3 mm ( 1 ⁄ 16 to 1 ⁄ 8  in) long, with a slender, 7 to 12 mm ( 1 ⁄ 4 to 1 ⁄ 2  in)-long pale pink–brown wing. There are three taxa , two subspecies and

1120-710: A traveler passes through the Cascade Range, the climate first gets colder, then warmer and drier east of the crest. Most of the Cascades' lower and middle elevations are covered in coniferous forest ; the higher altitudes have extensive meadows as well as alpine tundra and glaciers . The southern part of the Cascades are within the California Floristic Province , an area of high biodiversity . Silver fir predominates above 2500 ft, while there are moors , meadows , and mountain hemlock / subalpine fir groves from 4500 to 6000 ft on

1232-445: Is tolerant of shade and other forms of competition. It is more shade-tolerant than all of its associates except Pacific silver fir , western hemlock, and Alaska cedar . Mountain hemlock is considered a minor climax species on most of its habitats, and pioneers on glacial moraines in British Columbia and Alaska. In many communities of the mountain hemlock forest in British Columbia and Washington and northern Oregon, Pacific silver fir

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1344-479: Is 4,280 m (14,040 ft; 2,340 fathoms), putting the total water volume at roughly 710,000,000 km (170,000,000 cu mi). Due to the effects of plate tectonics , the Pacific Ocean is currently shrinking by roughly 2.5 cm (1 in) per year on three sides, roughly averaging 0.52 km (0.20 sq mi) a year. By contrast, the Atlantic Ocean is increasing in size. Along

1456-435: Is a major climax species. Alaska cedar, western redcedar , and western hemlock are climax associates on some sites. Mountain hemlock is more commonly the major climax species in the mountain hemlock zone south of central Oregon where Pacific silver fir does not occur. Mountain hemlock often succeeds lodgepole pine or subalpine fir when these species pioneer on drier sites. It also tends to replace Engelmann spruce when

1568-470: Is a part of the American Cordillera , a nearly continuous chain of mountain ranges (cordillera) that form the western "backbone" of North, Central , and South America . The Cascades are home to many national parks and protected areas, including North Cascades National Park , Mount Rainier National Park , Crater Lake National Park , and Lassen Volcanic National Park . The northern half of

1680-401: Is a species of hemlock native to the west coast of North America , found between Southcentral Alaska and south- central California . Tsuga mertensiana is a large evergreen conifer growing up to 20 to 40 meters (66 to 131 feet) tall, with exceptional specimens as tall as 59 m (194 ft) tall. They have a trunk diameter of up to 2 m ( 6 + 1 ⁄ 2  ft). The bark

1792-761: Is about 3 centimeters ( 1 + 1 ⁄ 4 inches) thick and square-cracked or furrowed, and purplish-brown to gray in color. The crown is a neat, slender, conic shape in young trees with a tilted or drooping lead shoot, becoming cylindric in older trees. At all ages, it is distinguished by the slightly pendulous branchlet tips. The shoots are orange–brown, with dense pubescence about 1 millimeter ( 1 ⁄ 16  in) long. The leaves are needle-like, 7 to 25 mm ( 1 ⁄ 4 to 1 in) long and 1 to 1.5 mm ( 1 ⁄ 32 to 1 ⁄ 16  in) broad, soft, blunt-tipped, only slightly flattened in cross-section, pale glaucous blue-green above, and with two broad bands of bluish-white stomata below with only

1904-444: Is adapted to sites with long-lasting snowpacks . In the spring, mountain hemlocks emerging through 2 to 4 m ( 6 + 1 ⁄ 2 to 13 ft) of snow were transpiring , whereas nearby whitebark pines did not transpire until the soil beneath them was free of snow. Mountain hemlock is well adapted to cope with heavy snow and ice loads , with tough branches and the drooping branchlets shedding snow readily. Mountain hemlock

2016-544: Is an arid plateau that was largely formed 17 to 14 million years ago by the many flows of the Columbia River Basalt Group . Together, these sequences of fluid volcanic rock form the 200,000-square-mile (520,000 km) Columbia Plateau in eastern Washington, Oregon, and parts of western Idaho. The Columbia River Gorge is the only major break of the range in the United States. When

2128-762: Is an interpretive site there now at "The End of The Oregon Trail". The road was constructed as a toll road – $ 5 per wagon – and was very successful. In addition, the Applegate Trail was created to allow settlers to avoid rafting down the Columbia River. The Trail used the path of the California Trail to north-central Nevada . From there, the Trail headed northwest into northern California, and continued northwest towards today's Ashland, Oregon . From there, settlers would head north along

2240-701: Is known as the North Cascades in the United States but is formally named the Cascade Mountains north of the Canada–United States border , reaching to the northern extremity of the Cascades at Lytton Mountain . Overall, the North Cascades and Canadian Cascades are extremely rugged; even the lesser peaks are steep and glaciated, and valleys are quite low relative to peaks and ridges, so there is great local relief . The southern part of

2352-491: Is not known with any certainty what level of maritime technology was used by these groups – the presumption is that they used large bamboo rafts which may have been equipped with some sort of sail. The reduction in favourable winds for a crossing to Sahul after 58,000 B.P. fits with the dating of the settlement of Australia, with no later migrations in the prehistoric period. The seafaring abilities of pre-Austronesian residents of Island South-east Asia are confirmed by

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2464-463: Is not uncommon for some places in the Cascades to have over 500 inches (1,300 cm) of annual snow accumulation, such as at Lake Helen , near Lassen Peak. Most of the High Cascades are therefore white with snow and ice year-round. The western slopes are densely covered with Douglas-fir ( Pseudotsuga menziesii ), western hemlock ( Tsuga heterophylla ) and red alder ( Alnus rubra ), while

2576-429: Is usually found on cold, snowy subalpine sites where it grows slowly, sometimes attaining more than 800 years in age. Arborescent individuals that have narrowly conical crowns until old age (300 to 400 years) and shrubby krummholz on cold, windy sites near timberline add beauty to mountain landscapes. Areas occupied by mountain hemlock generally have a cool to cold maritime climate that includes mild to cold winters,

2688-697: The Americas , although evidence for this remains inconclusive. The first contact of European navigators with the western edge of the Pacific Ocean was made by the Portuguese expeditions of António de Abreu and Francisco Serrão , via the Lesser Sunda Islands , to the Maluku Islands , in 1512, and with Jorge Álvares 's expedition to southern China in 1513, both ordered by Afonso de Albuquerque from Malacca . The eastern side of

2800-489: The Baker River is dammed to form Lake Shannon and Baker Lake . The Cascades harbor a largely-untapped potential for geothermal power . The U.S. Geological Survey Geothermal Research Program has been investigating this potential. Some of this energy is already being used in places like Klamath Falls, Oregon , where volcanic steam is used to heat public buildings. The highest recorded underground temperature found in

2912-575: The Bering Sea in the Arctic to the northern extent of the circumpolar Southern Ocean at 60°S (older definitions extend it to Antarctica 's Ross Sea ), the Pacific reaches its greatest east–west width at about 5°N latitude , where it stretches approximately 19,800 km (12,300 mi) from Indonesia to the coast of Colombia  – halfway around the world, and more than five times

3024-624: The Cascades Rapids in the Columbia River Gorge, a feature on the river now submerged beneath the Bonneville Reservoir . Before long, the great white-capped mountains that loomed above the rapids were called the "mountains by the cascades" and later simply as the "Cascades". The earliest attested use of the name "Cascade Range" is in the writings of botanist David Douglas in 1825. In 1814, Alexander Ross ,

3136-775: The Coast Ranges and mountain hemlock is found in the Klamath Mountains and Sierra Nevada . Unlike western hemlock, mountain hemlock mostly grows at high altitudes except in the far north, from sea level to 1,000 m (3,300 ft) in Alaska, 1,600 to 2,300 m (5,200 to 7,500 ft) in the Cascades in Oregon , and 2,500 to 3,050 m (8,200 to 10,010 ft) in the Sierra Nevada. Mountain hemlock

3248-664: The Hudson's Bay Company (HBC) at Fort Vancouver near today's Portland, Oregon . From this base HBC trapping parties traveled throughout the Cascades in search of beaver and other fur-bearing animals. For example, using what became known as the Siskiyou Trail , Hudson's Bay Company trappers were the first non-natives to explore the southern Cascades in the 1820s and 1830s, establishing trails which passed near Crater Lake , Mount McLoughlin , Medicine Lake Volcano , Mount Shasta , and Lassen Peak. The course of political history in

3360-829: The International Date Line into the East Pacific and the West Pacific , which allows it to be further divided into four quadrants, namely the Northeast Pacific off the coasts of North America , the Southeast Pacific off South America , Northwest Pacific off Far Eastern / Pacific Asia , and the Southwest Pacific around Oceania . The Pacific Ocean's mean depth is 4,000 meters (13,000 feet). Challenger Deep in

3472-524: The Lushootseed name for Mount Rainier, and "Louwala-Clough", meaning "smoking mountain" for Mount St. Helens. In early 1792, British navigator George Vancouver explored Puget Sound and gave English names to the high mountains he saw. Mount Baker was named for Vancouver's third lieutenant, Joseph Baker , although the first European to see it was Manuel Quimper , who named it la gran montaña del Carmelo ("Great Mount Carmel ") in 1790. Mount Rainier

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3584-830: The Mariana Trench , located in the northwestern Pacific, is the deepest known point in the world, reaching a depth of 10,928 meters (35,853 feet). The Pacific also contains the deepest point in the Southern Hemisphere , the Horizon Deep in the Tonga Trench , at 10,823 meters (35,509 feet). The third deepest point on Earth, the Sirena Deep , is also located in the Mariana Trench. The western Pacific has many major marginal seas , including

3696-527: The North American Plate . As the oceanic slab sinks deep into the Earth's interior beneath the continental plate, high temperatures and pressures allow water molecules locked in the minerals of solid rock to escape. The water vapor rises into the pliable mantle above the subducting plate, causing some of the mantle to melt. This newly formed magma rises toward the Earth's surface to erupt, forming

3808-857: The Pacific Crest Trail follows the range. The Cascades extend northward from Lassen Peak (also known as Mount Lassen) in northern California to the confluence of the Nicola and Thompson rivers in British Columbia . The Fraser River separates the Cascades from the Coast Mountains in Canada, as does the Willamette Valley from the upper portion of the Oregon Coast Range . The highest volcanoes of

3920-688: The Pacific Northwest saw the spine of the Cascade Range being proposed as a boundary settlement during the Oregon Dispute of 1846. The United States rejected the proposal and insisted on the 49th parallel north , which cuts across the range just north of Mount Baker. Throughout the period of dispute and up to the creation of the Crown Colony of British Columbia in 1858, the Hudson's Bay Company's York Factory Express route, as well

4032-525: The Pacific Ocean , apart from an inland population in the Rocky Mountains in southeast British Columbia , northern Idaho , and western Montana . The inland populations most likely established after deglaciation by remarkable long-distance dispersal of more than 200 km (120 mi) from the coast populations. Their ranges differ in California , where western hemlock is restricted to

4144-538: The Pacific War ; however, by the end of that war, Japan was defeated and the U.S. Pacific Fleet was the virtual master of the ocean. The Japanese-ruled Northern Mariana Islands came under the control of the United States. Since the end of World War II, many former colonies in the Pacific have become independent states . The Pacific separates Asia and Australia from the Americas. It may be further subdivided by

4256-631: The Philippine Sea , South China Sea , East China Sea , Sea of Japan , Sea of Okhotsk , Bering Sea , Gulf of Alaska , Gulf of California , Mar de Grau , Tasman Sea , and the Coral Sea . In the early 16th century , Spanish explorer Vasco Núñez de Balboa crossed the Isthmus of Panama in 1513 and sighted the great "Southern Sea" which he named Mar del Sur (in Spanish). Afterwards,

4368-715: The Southern Hemisphere . The North Equatorial Current , driven westward along latitude 15°N by the trade winds , turns north near the Philippines to become the warm Japan or Kuroshio Current . Turning eastward at about 45°N , the Kuroshio forks and some water moves northward as the Aleutian Current , while the rest turns southward to rejoin the North Equatorial Current. The Aleutian Current branches as it approaches North America and forms

4480-685: The Strait of Magellan to the Philippines , the explorer indeed found the ocean peaceful; however, the Pacific is not always peaceful. Many tropical storms batter the islands of the Pacific. The lands around the Pacific Rim are full of volcanoes and often affected by earthquakes . Tsunamis , caused by underwater earthquakes, have devastated many islands and in some cases destroyed entire towns. The Martin Waldseemüller map of 1507

4592-800: The Water Hemisphere and the Western Hemisphere , as well as the oceanic pole of inaccessibility , are in the Pacific Ocean. Ocean circulation (caused by the Coriolis effect ) subdivides it into two largely independent volumes of water that meet at the equator , the North Pacific Ocean and the South Pacific Ocean (or more loosely the South Seas ). The Pacific Ocean can also be informally divided by

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4704-750: The Western Hemisphere . The Southern Pacific Ocean harbors the Southeast Indian Ridge crossing from south of Australia turning into the Pacific-Antarctic Ridge (north of the South Pole ) and merges with another ridge (south of South America) to form the East Pacific Rise which also connects with another ridge (south of North America) which overlooks the Juan de Fuca Ridge . For most of Magellan's voyage from

4816-446: The crab claw sail ) – it is likely that the progressive development of these technologies were related to the later steps of settlement into Near and Remote Oceania. Starting at around 2200 BCE, Austronesians sailed southwards to settle the Philippines . From, probably, the Bismarck Archipelago they crossed the western Pacific to reach the Marianas Islands by 1500 BCE, as well as Palau and Yap by 1000 BCE. They were

4928-469: The railway roadbed and the Othello Tunnels , now decommissioned, are popular tourist recreation destinations for hiking and bicycling. The pass is used by the Coquihalla Highway , a government megaproject built as part of the Expo 86 spending boom of the 1980s, which is now the main route from the Coast to the British Columbia interior. Traffic formerly went via the Fraser Canyon , to the west, or via Allison Pass and Manning Park along Highway 3 to

5040-414: The Atlantic, the Strait of Magellan was at times patrolled by fleets sent to prevent the entrance of non-Spanish ships. On the western side of the Pacific Ocean the Dutch threatened the Spanish Philippines . The 18th century marked the beginning of major exploration by the Russians in Alaska and the Aleutian Islands , such as the First Kamchatka expedition and the Great Northern Expedition , led by

5152-405: The Atlantic. The andesite line is the most significant regional distinction in the Pacific. A petrologic boundary, it separates the deeper, mafic igneous rock of the Central Pacific Basin from the partially submerged continental areas of felsic igneous rock on its margins. The andesite line follows the western edge of the islands off California and passes south of the Aleutian arc , along

5264-404: The Canadian Cascades, particularly the Skagit Range , is geologically and topographically similar to the North Cascades, while the northern and northeastern parts are less glaciated and more plateau-like, resembling nearby areas of the Thompson Plateau . The range is near the Pacific Ocean and in the region's prevailing westerly winds , so it receives significant rain and snowfall, especially on

5376-547: The Cascades began to rise 7 million years ago in the late Miocene , the Columbia River drained the relatively low Columbia Plateau. As the range grew, erosion from the Columbia River was able to keep pace, carving out the gorge and major pass seen today. The gorge also exposes uplifted and warped layers of basalt from the plateau. Before European exploration, First Nations tribes named many peaks, including "Wy'east" for Mount Hood , "Seekseekqua" for Mount Jefferson (Oregon) , "M'laiksini Yaina" for Mount McLoughlin , "Tahoma",

5488-413: The Cascades, known as the High Cascades, dominate their surroundings, often standing twice the height of the nearby mountains. They often have a visual height (height above nearby crestlines) of one mile or more. The highest peaks, such as the 14,411-foot (4,392 m) Mount Rainier, dominate their surroundings for 50 to 100 miles (80 to 161 km). The northern part of the range, north of Mount Rainier,

5600-433: The Chilean coast, the South Equatorial Current divides; one branch flows around Cape Horn and the other turns north to form the Peru or Humboldt Current . The climate patterns of the Northern and Southern Hemispheres generally mirror each other. The trade winds in the southern and eastern Pacific are remarkably steady while conditions in the North Pacific are far more varied with, for example, cold winter temperatures on

5712-499: The Danish-born Russian navy officer Vitus Bering . Spain also sent expeditions to the Pacific Northwest , reaching Vancouver Island in southern Canada, and Alaska. The French explored and colonized Polynesia , and the British made three voyages with James Cook to the South Pacific and Australia, Hawaii , and the North American Pacific Northwest . In 1768, Pierre-Antoine Véron , a young astronomer accompanying Louis Antoine de Bougainville on his voyage of exploration, established

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5824-498: The Moluccas, between 1525 and 1527, Portuguese expeditions encountered the Caroline Islands , the Aru Islands , and Papua New Guinea . In 1542–43 the Portuguese also reached Japan. In 1564, five Spanish ships carrying 379 soldiers crossed the ocean from Mexico led by Miguel López de Legazpi , and colonized the Philippines and Mariana Islands . For the remainder of the 16th century, Spain maintained military and mercantile control, with ships sailing from Mexico and Peru across

5936-487: The Pacific Ring of Fire is the world's foremost belt of explosive volcanism . The Ring of Fire is named after the several hundred active volcanoes that sit above the various subduction zones. The Pacific Ocean is the only ocean which is mostly bounded by subduction zones. Only the central part of the North American coast and the Antarctic and Australian coasts have no nearby subduction zones. Mountain hemlock Tsuga mertensiana , known as mountain hemlock ,

6048-429: The Pacific Ocean to the Philippines via Guam , and establishing the Spanish East Indies . The Manila galleons operated for two and a half centuries, linking Manila and Acapulco , in one of the longest trade routes in history. Spanish expeditions also arrived at Tuvalu , the Marquesas , the Cook Islands , the Solomon Islands , Vanuatu , the Marshalls and the Admiralty Islands in the South Pacific. Later, in

6160-399: The Pacific Ocean's irregular western margins lie many seas, the largest of which are the Celebes Sea , Coral Sea , East China Sea (East Sea), Philippine Sea , Sea of Japan , South China Sea (South Sea), Sulu Sea , Tasman Sea , and Yellow Sea (West Sea of Korea). The Indonesian Seaway (including the Strait of Malacca and Torres Strait ) joins the Pacific and the Indian Ocean to

6272-413: The Pacific in prehistoric times. Modern humans first reached the western Pacific in the Paleolithic , at around 60,000 to 70,000 years ago. Originating from a southern coastal human migration out of Africa, they reached East Asia , Mainland Southeast Asia , the Philippines, New Guinea , and then Australia by making the sea crossing of at least 80 kilometres (50 mi) between Sundaland and Sahul . It

6384-402: The Pacific in recorded history. They were part of a Spanish expedition to the Spice Islands that would eventually result in the first world circumnavigation . Magellan called the ocean Pacífico (or "Pacific" meaning, "peaceful") because, after sailing through the stormy seas off Cape Horn , the expedition found calm waters. The ocean was often called the Sea of Magellan in his honor until

6496-540: The Philippines already in 7000 BCE. Additional earlier migrations into Insular Southeast Asia, associated with Austroasiatic-speakers from Mainland Southeast Asia, are estimated to have taken place already in 15000 BCE. At around 1300 to 1200 BCE, a branch of the Austronesian migrations known as the Lapita culture reached the Bismarck Archipelago , the Solomon Islands , Vanuatu , Fiji , and New Caledonia . From there, they settled Tonga and Samoa by 900 to 800 BCE. Some also back-migrated northwards in 200 BCE to settle

6608-528: The United States. Significant contributions to oceanographic knowledge were made by the voyages of HMS Beagle in the 1830s, with Charles Darwin aboard; HMS Challenger during the 1870s; the USS Tuscarora (1873–76); and the German Gazelle (1874–76). In Oceania, France obtained a leading position as imperial power after making Tahiti and New Caledonia protectorates in 1842 and 1853, respectively. After navy visits to Easter Island in 1875 and 1887, Chilean navy officer Policarpo Toro negotiated

6720-416: The andesite line and include New Guinea, the islands of New Zealand, and the Philippines. Some of these islands are structurally associated with nearby continents. High islands are of volcanic origin, and many contain active volcanoes. Among these are Bougainville , Hawaii, and the Solomon Islands. The coral reefs of the South Pacific are low-lying structures that have built up on basaltic lava flows under

6832-408: The andesite line. Within the closed loop of the andesite line are most of the deep troughs, submerged volcanic mountains, and oceanic volcanic islands that characterize the Pacific basin. Here basaltic lavas gently flow out of rifts to build huge dome-shaped volcanic mountains whose eroded summits form island arcs, chains, and clusters. Outside the andesite line, volcanism is of the explosive type, and

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6944-409: The arctic, icing from October to May can present a hazard for shipping while persistent fog occurs from June to December. A climatological low in the Gulf of Alaska keeps the southern coast wet and mild during the winter months. The Westerlies and associated jet stream within the Mid-Latitudes can be particularly strong, especially in the Southern Hemisphere, due to the temperature difference between

7056-421: The base of a counter-clockwise circulation in the Bering Sea . Its southern arm becomes the chilled slow, south-flowing California Current . The South Equatorial Current , flowing west along the equator, swings southward east of New Guinea , turns east at about 50°S , and joins the main westerly circulation of the South Pacific, which includes the Earth-circling Antarctic Circumpolar Current . As it approaches

7168-408: The diameter of the Moon. Its geographic center is in eastern Kiribati south of Kiritimati , just west from Starbuck Island at 4°58′S 158°45′W  /  4.97°S 158.75°W  / -4.97; -158.75 . The lowest known point on Earth – the Mariana Trench  – lies 10,911 m (35,797  ft ; 5,966 fathoms ) below sea level. Its average depth

7280-402: The difference between temperatures aloft and sea surface temperatures is the greatest; however, each particular basin has its own seasonal patterns. On a worldwide scale, May is the least active month, while September is the most active month. November is the only month in which all the tropical cyclone basins are active. The Pacific hosts the two most active tropical cyclone basins , which are

7392-412: The drier eastern slopes feature mostly ponderosa pine ( Pinus ponderosa ), with some western larch ( Larix occidentalis ), mountain hemlock ( Tsuga mertensiana ) and subalpine fir ( Abies lasiocarpa ) and subalpine larch ( Larix lyallii ) at higher elevations. Annual rainfall is as low as 9 inches (230 mm) on the eastern foothills due to a rain shadow effect. Beyond the eastern foothills

7504-439: The early 1840s, at first only marginally. Following the Oregon Treaty the inward flux of migration from the Oregon Trail intensified and the passes and back-valleys of what is now the state of Washington were explored and populated, and it was not long after that railways followed. Despite its being traversed by several major freeways and rail lines, and its lower flanks subjected to major logging in recent decades, large parts of

7616-434: The east and the islands of Kiribati in the southeast. Melanesia, to the southwest, includes New Guinea , the world's second largest island after Greenland and by far the largest of the Pacific islands. The other main Melanesian groups from north to south are the Bismarck Archipelago , the Solomon Islands , Santa Cruz , Vanuatu , Fiji and New Caledonia . The largest area, Polynesia , stretching from Hawaii in

7728-423: The east coast of Russia contrasting with the milder weather off British Columbia during the winter months due to the preferred flow of ocean currents . In the tropical and subtropical Pacific, the El Niño Southern Oscillation (ENSO) affects weather conditions. To determine the phase of ENSO, the most recent three-month sea surface temperature average for the area approximately 3,000 km (1,900 mi) to

7840-403: The eastern edge of the Kamchatka Peninsula , the Kuril Islands , Japan, the Mariana Islands , the Solomon Islands , and New Zealand's North Island . The dissimilarity continues northeastward along the western edge of the Andes Cordillera along South America to Mexico, returning then to the islands off California. Indonesia, the Philippines, Japan, New Guinea, and New Zealand lie outside

7952-410: The eighteenth century. Magellan stopped at one uninhabited Pacific island before stopping at Guam in March 1521. Although Magellan himself died in the Philippines in 1521, Spanish navigator Juan Sebastián Elcano led the remains of the expedition back to Spain across the Indian Ocean and round the Cape of Good Hope , completing the first world circumnavigation in 1522. Sailing around and east of

8064-595: The equator into northern (North Pacific) and southern (South Pacific) portions. It extends from the Antarctic region in the South to the Arctic in the north. The Pacific Ocean encompasses approximately one-third of the Earth's surface, having an area of 165,200,000 km (63,800,000 sq mi) – larger than Earth's entire landmass combined, 150,000,000 km (58,000,000 sq mi). Extending approximately 15,500 km (9,600 mi) from

8176-601: The equator, which can have a salinity as low as 34 parts per thousand, is less salty than that found in the mid-latitudes because of abundant equatorial precipitation throughout the year. The lowest counts of less than 32 parts per thousand are found in the far north as less evaporation of seawater takes place in these frigid areas. The motion of Pacific waters is generally clockwise in the Northern Hemisphere (the North Pacific gyre ) and counter-clockwise in

8288-596: The established Siskiyou Trail into the Willamette Valley . With the exception of the 1915 eruption of remote Lassen Peak in Northern California, the range was quiet for more than a century. Then, on May 18, 1980, the dramatic eruption of Mount St. Helens shattered the quiet and brought the world's attention to the range. Geologists were also concerned that the St. Helens eruption was a sign that long-dormant Cascade volcanoes might become active once more, as in

8400-606: The first completely documented European landing in Australia (1606), in Cape York Peninsula , and Abel Janszoon Tasman circumnavigated and landed on parts of the Australian continental coast and arrived at Tasmania and New Zealand in 1642. In the 16th and 17th centuries, Spain considered the Pacific Ocean a mare clausum  – a sea closed to other naval powers. As the only known entrance from

8512-534: The first humans to reach Remote Oceania , and the first to cross vast distances of open water. They also continued spreading southwards and settling the rest of Maritime Southeast Asia , reaching Indonesia and Malaysia by 1500 BCE, and further west to Madagascar and the Comoros in the Indian Ocean by around 500 CE. More recently, it is suggested that Austronesians expanded already earlier, arriving in

8624-465: The first to explore the Stehekin River and Bridge Creek region. Due to the difficulty of crossing the northern Cascades and the paucity of beaver, fur-trading companies made only a few explorations into the mountains north of the Columbia River after Ross. Exploration and settlement of the Cascades region by Europeans and Americans was accelerated by the establishment of a major trading post of

8736-421: The form of snow and ice is also important for agriculture. The snow-capped mountains, such as Mt. Hood and Mt. Bachelor , are used as ski resorts in the late winter, while in the summer they become popular hiking and mountaineering locations. Much of their meltwater eventually flows into reservoirs, where it is used for recreation, while its potential energy is captured to generate hydroelectric power before

8848-439: The incorporation of the island into Chile with native Rapanui in 1888. By occupying Easter Island, Chile joined the imperial nations. By 1900 nearly all Pacific islands were in control of Britain, France, United States, Germany, Japan, and Chile. Although the United States gained control of Guam and the Philippines from Spain in 1898, Japan controlled most of the western Pacific by 1914 and occupied many other islands during

8960-613: The islands in the world. There are about 25,000 islands in the Pacific Ocean. The islands entirely within the Pacific Ocean can be divided into three main groups known as Micronesia , Melanesia and Polynesia . Micronesia, which lies north of the equator and west of the International Date Line , includes the Mariana Islands in the northwest, the Caroline Islands in the center, the Marshall Islands to

9072-752: The islands of eastern Micronesia (including the Carolines , the Marshall Islands , and Kiribati ), mixing with earlier Austronesian migrations in the region. This remained the furthest extent of the Austronesian expansion into Polynesia until around 700 CE when there was another surge of island exploration. They reached the Cook Islands , Tahiti , and the Marquesas by 700 CE; Hawaiʻi by 900 CE; Rapa Nui by 1000 CE; and finally New Zealand by 1200 CE. Austronesians may have also reached as far as

9184-426: The mid-20th century, the species has been used for lumber, often mixed with western hemlock. Outside of its native range, mountain hemlock is grown as an ornamental tree . It is planted as a specimen tree in native plant landscapes in California, and particularly in gardens in northern Great Britain and Scandinavia , where it is appreciated for its blue–green color and tolerance of severe weather. Cultivation

9296-492: The mountain range which contained these peaks. He referred to it simply as the "eastern snowy range". Earlier Spanish explorers called it Sierra Nevada , meaning "snowy mountains". In 1805, the Lewis and Clark Expedition passed through the Cascades on the Columbia River, which for many years was the only practical way to pass that part of the range. They were the first non-indigenous people to see Mount Adams , but they thought it

9408-601: The north to New Zealand in the south, also encompasses Tuvalu , Tokelau , Samoa , Tonga and the Kermadec Islands to the west, the Cook Islands , Society Islands and Austral Islands in the center, and the Marquesas Islands , Tuamotu , Mangareva Islands , and Easter Island to the east. Islands in the Pacific Ocean are of four basic types: continental islands, high islands, coral reefs and uplifted coral platforms. Continental islands lie outside

9520-619: The northern Philippines , but also earlier groups associated with Austroasiatic-speakers , resulting in the modern peoples of Island Southeast Asia and Oceania. A later seaborne migration is the Neolithic Austronesian expansion of the Austronesian peoples . Austronesians originated from the island of Taiwan c.  3000 –1500 BCE. They are associated with distinctive maritime sailing technologies (notably outrigger boats , catamarans , lashed-lug boats, and

9632-575: The northwestern Pacific and the eastern Pacific. Pacific hurricanes form south of Mexico, sometimes striking the western Mexican coast and occasionally the Southwestern United States between June and October, while typhoons forming in the northwestern Pacific moving into southeast and east Asia from May to December. Tropical cyclones also form in the South Pacific basin , where they occasionally impact island nations. In

9744-399: The ocean was encountered by Spanish explorer Vasco Núñez de Balboa in 1513 after his expedition crossed the Isthmus of Panama and reached a new ocean. He named it Mar del Sur ("Sea of the South" or "South Sea" ) because the ocean was to the south of the coast of the isthmus where he first observed the Pacific. In 1520, navigator Ferdinand Magellan and his crew were the first to cross

9856-465: The ocean's current name was coined by Portuguese explorer Ferdinand Magellan during the Spanish circumnavigation of the world in 1521, as he encountered favorable winds on reaching the ocean. He called it Mar Pacífico , which in Portuguese means 'peaceful sea'. Top large seas: Across the continents of Asia, Australia and the Americas , more than 25,000 islands, large and small, rise above

9968-562: The ocean's surface. One of the most dramatic is the Great Barrier Reef off northeastern Australia with chains of reef patches. A second island type formed of coral is the uplifted coral platform, which is usually slightly larger than the low coral islands. Examples include Banaba (formerly Ocean Island) and Makatea in the Tuamotu group of French Polynesia . The volume of the Pacific Ocean, representing about 50.1 percent of

10080-774: The older Hudson's Bay Company Brigade Trail from the Canyon to the Interior, the Dewdney Trail, and older routes which connected east to the Similkameen and Okanagan valleys. The southern mainline of the Canadian Pacific Railway penetrated the range via the passes of the Coquihalla River , along one of the steepest and snowiest routes in the entire Pacific Cordillera . Near Hope, B.C. ,

10192-596: The period from 1800 to 1857 when a total of eight erupted. None have erupted since St. Helens, but precautions are being taken nevertheless, such as the Cascades Volcano Observatory and Mount Rainier Volcano Lahar Warning System in Pierce County, Washington . The Cascade Range is made up of a band of thousands of very small, short-lived volcanoes that have built a platform of lava and volcanic debris. Rising above this volcanic platform are

10304-581: The quest for Terra Australis ("the [great] Southern Land"), Spanish explorations in the 17th century, such as the expedition led by the Portuguese navigator Pedro Fernandes de Queirós , arrived at the Pitcairn and Vanuatu archipelagos, and sailed the Torres Strait between Australia and New Guinea, named after navigator Luís Vaz de Torres . Dutch explorers, sailing around southern Africa, also engaged in exploration and trade; Willem Janszoon , made

10416-464: The range is 510 °F (266 °C) at 3,075 feet (937 m) below Newberry Volcano 's caldera floor. Forests of large, coniferous trees ( western red cedars , Douglas-firs, western hemlocks, firs , pines , spruces , and others) dominate most of the Cascade Range. Cool, wet winters and warm, dry summers (largely a result of oceanic influence) favor evergreen species, whereas mild temperatures and rich soils promote fast and prolonged growth. As

10528-494: The range remain intense and forbidding alpine wilderness. Much of the northern half of the Cascades, from Rainier north, have been preserved by U.S. national or British Columbia provincial parks (such as E.C. Manning Provincial Park ), or other forms of protected area. The Canadian side of the range has a history that includes the Fraser Canyon Gold Rush of 1858–60 and its famous Cariboo Road , as well as

10640-523: The route of fur brigades, followed the Okanogan River along the east edge of the Cascades and the Columbia River through the range. Passes across the range were not well known and little used. Naches Pass was used for driving cattle and horses to Fort Nisqually . Yakima Pass was also used by the Hudson's Bay Company. American settlement of the flanks of the Coast Range did not occur until

10752-505: The settlement of Buka by 32,000 B.P. and Manus by 25,000 B.P. Journeys of 180 kilometres (110 mi) and 230 kilometres (140 mi) are involved, respectively. The descendants of these migrations today are the Negritos , Melanesians , and Indigenous Australians . Their populations in maritime Southeast Asia , coastal New Guinea , and Island Melanesia later intermarried with the incoming Austronesian settlers from Taiwan and

10864-550: The south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east. At 165,250,000 square kilometers (63,800,000 square miles) in area (as defined with a southern Antarctic border), this largest division of the World Ocean and the hydrosphere covers about 46% of Earth's water surface and about 32% of the planet's total surface area, larger than its entire land area (148,000,000 km (57,000,000 sq mi)). The centers of both

10976-691: The south, near the border. The Barlow Road was the first established land path for U.S. settlers through the Cascade Range in 1845, and formed the final overland link for the Oregon Trail (previously, settlers had to raft down the treacherous rapids of the Columbia River). The Road left the Columbia at what is now Hood River and passed along the south side of Mount Hood at what is now Government Camp , terminating in Oregon City. There

11088-504: The southeast of Hawaii is computed, and if the region is more than 0.5 °C (0.9 °F) above or below normal for that period, then an El Niño or La Niña is considered in progress. In the tropical western Pacific, the monsoon and the related wet season during the summer months contrast with dry winds in the winter which blow over the ocean from the Asian landmass. Worldwide, tropical cyclone activity peaks in late summer, when

11200-415: The surface of the Pacific Ocean. Multiple islands were the shells of former active volcanoes that have lain dormant for thousands of years. Close to the equator, without vast areas of blue ocean, are a dot of atolls that have over intervals of time been formed by seamounts as a result of tiny coral islands strung in a ring within surroundings of a central lagoon . Important human migrations occurred in

11312-463: The tree grows better on northerly exposures. The preference for relatively moist, cool sites evidently becomes a necessity as the climate becomes more continental in western Montana and more mediterranean in the central Sierra Nevada at these extremes of its range. In these locations, mountain hemlock typically grows in isolated populations in north-facing glens and cirque basins where snow collects and may remain well into summer. Mountain hemlock

11424-804: The tropics and Antarctica, which records the coldest temperature readings on the planet. In the Southern hemisphere, because of the stormy and cloudy conditions associated with extratropical cyclones riding the jet stream, it is usual to refer to the Westerlies as the Roaring Forties, Furious Fifties and Shrieking Sixties according to the varying degrees of latitude. The ocean was first mapped by Abraham Ortelius ; he called it Maris Pacifici following Ferdinand Magellan 's description of it as "a pacific sea" during his circumnavigation from 1519 to 1522. To Magellan, it seemed much more calm (pacific) than

11536-479: The two species occur together, possibly because hemlock is better able to withstand the allelopathic effects of spruce than are other associated species. The species is attacked by the root rot Phellinus weirii . Stands lost to fire can be populated by lodgepole pine, which is in turn succeeded by mountain hemlock. Native Americans used the species less often than western hemlock, but specifically used mountain hemlock boughs as beds and bathing brushes. Since

11648-450: The water is used to irrigate crops. Because of the abundance of powerful streams, many of the major westward-draining rivers of the Cascades have been dammed to provide hydroelectric power . One of these, Ross Dam on the Skagit River , retains a reservoir which spans the border southeast of Hope, British Columbia , extending 2 miles (3.2 km) into Canada. At the foot of the southeast flank of Mount Baker, at Concrete, Washington ,

11760-470: The west side. The treeline is at ~6000 feet. On the east side, subalpine forests of larch trees grade to pine and interior fir forests below 4200 ft, which grade to ponderosa below 2500 ft, which in turn grades to semidesert scrub near sea level. Above 7500 ft, the landscape is barren with either no plants or only moss and lichen . Black bears , coyotes , bobcats , cougars , beavers , deer , elk , moose , mountain goats and

11872-586: The west, and Drake Passage and the Strait of Magellan link the Pacific with the Atlantic Ocean on the east. To the north, the Bering Strait connects the Pacific with the Arctic Ocean . As the Pacific straddles the 180th meridian , the West Pacific (or western Pacific , near Asia) is in the Eastern Hemisphere , while the East Pacific (or eastern Pacific , near the Americas) is in

11984-534: The western slopes due to orographic lift , with annual snow accumulations of up to 1,000 inches (2,500 cm) (= 83 feet (25 m)) in some areas. Mount Baker in Washington recorded a national record single-season snowfall in the winter of 1998–99 with 1,140 inches (2,900 cm) (= 95 feet (29 m)). Before that year, Mount Rainier held the American record for snow accumulation at Paradise in 1978. It

12096-597: The width of the Pacific with precision for the first time in history. One of the earliest voyages of scientific exploration was organized by Spain in the Malaspina Expedition of 1789–1794. It sailed vast areas of the Pacific, from Cape Horn to Alaska, Guam and the Philippines, New Zealand, Australia, and the South Pacific. Growing imperialism during the 19th century resulted in the occupation of much of Oceania by European powers, and later Japan and

12208-434: The world's oceanic water, has been estimated at some 714 million cubic kilometers (171 million cubic miles). Surface water temperatures in the Pacific can vary from −1.4 °C (29.5 °F), the freezing point of seawater, in the poleward areas to about 30 °C (86 °F) near the equator. Salinity also varies latitudinally, reaching a maximum of 37 parts per thousand in the southeastern area. The water near

12320-454: Was Mount St. Helens. When they later saw Mount St. Helens they thought it was Mount Rainier. On their return trip, Lewis and Clark spotted a high but distant snowy pinnacle that they named for the sponsor of the expedition, U.S. President Thomas Jefferson . Lewis and Clark called the Cascade Range the "Western Mountains". The Lewis and Clark expedition, and the many settlers and traders that followed, met their last obstacle to their journey at

12432-563: Was named after Admiral Peter Rainier . Later in 1792, Vancouver had his lieutenant William Robert Broughton explore the lower Columbia River . He named Mount Hood after Lord Samuel Hood , an admiral of the Royal Navy . Mount St. Helens was sighted by Vancouver in May 1792, from near the mouth of the Columbia River. It was named for Alleyne FitzHerbert, 1st Baron St Helens , a British diplomat. Vancouver's expedition did not, however, name

12544-583: Was the first to show the Americas separating two distinct oceans. Later, the Diogo Ribeiro map of 1529 was the first to show the Pacific at about its proper size. (Inhabited dependent territories are denoted by the asterisk (*), with names of the corresponding sovereign states in round brackets. Associated states in the Realm of New Zealand are denoted by the hash sign (#).) Territories with no permanent civilian population. The Pacific Ocean has most of

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