Auyuittuq National Park is a national park located on Baffin Island's Cumberland Peninsula, Qikiqtaaluk Region, in Nunavut, the largest political subdivision of Canada. It features the many terrains of Arctic wilderness, such as fjords, glaciers, and ice fields. In Inuktitut - the language of Nunavut's Aboriginal people, Inuit - Auyuittuq means "the land that never melts". Although Auyuittuq was established in 1976 as a national park reserve, it was upgraded to a full national park in 2000.

Little vegetation can be found in Auyuittuq Park, although the plants that are found there range from flowers such as Mountain Avens, Campion, Papaver, and Saxifrage to shrubs like Dwarf Birch, Arctic Willow, and heather. Many of the plants in Auyuittuq Park grow in clumps to create their own warmer "microclimate" to survive the harsh Arctic conditions.

Because of the exceptionally low vegetation supply, wildlife is very scarce. There are only 12 species of mammals that live in Auyuittuq Park and these range from Lemmings (both the North American Brown Lemming and the Northern Collared Lemming), Arctic Hare, and Ermine to Polar Bear, Arctic Fox, and some Barren-ground Caribou.

The nearest towns are Qikiqtarjuaq and Pangnirtung. Visitors wishing to enter the park are required to register at the park office in Pangnirtung or Qikiqtarjuaq, and attend an orientation session. Park user fees apply.

The most common backpacking route in the park is known as Akshayuk Pass, and follows the Weasel and Owl Rivers via Summit Lake. In 2008, heavy rain and warm weather caused Summit Lake to burst through its banks, flooding the Weasel River and washing away the Windy Lake bridge (see photo below). As a result, the hiking routes in the pass are limited to either side of the Weasel River.

Well known peaks include Mount Asgard (shown in the James Bond film The Spy Who Loved Me) with an 800 meter (2625 foot) face, and Mount Thor with a 1,250 meter (4,100 foot), 105° face.

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Parque Nacional de la Caldera de Taburiente is a national park on the island of La Palma, Canary Islands, Spain. It contains the enormous expanse of the Caldera de Taburiente, once believed to be a huge crater, but nowadays known to be a mountain arch with a curious crater shape, which dominates the northern part of the island. It was designated as a national park in 1954.

The caldera is about 10 km across, and in places the walls tower 2000 m over the caldera floor. The highest point is the Roque de los Muchachos on the northern wall, at 2423 m altitude, which can be reached by road. The telescopes of the Roque de los Muchachos Observatory are situated very close to the summit.

During the Spanish conquest of the Canary Islands in the 15th century, the caldera was the site of the last stand of the indigenous people of the archipelago, the Guanches. It proved impregnable to the invading Spaniards, and they only defeated the Guanches by luring their leader out on the pretext of holding talks.

The Cumbrecita is at a lower point in the south-eastern part of the caldera's rim, giving a good view into the Caldera. In the south-west the caldera opens to the sea, through a riverbed known as Barranco de las Augustias. The Cumbre Nueva is a ridge that starts at the caldera and continues to the south.

The main flora of the national park comprises a large forest of Canary Island Pine, with important population of the endangered Canary Islands Juniper also present.

Geological origins

The caldera originated some 2 million years ago, with a massive shield volcano about 20 km in diameter. The caldera was not formed by an explosion of that volcano however, but by erosion starting from the volcano's original crater.

Name

The word "caldera" means "cauldron" in Spanish. Its use for very large volcanic craters originated with the Caldera de Taburiente.

Taburiente is not a Spanish word but derives from the Guanche language and means "plain, level".

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Sequoia National Park is a national park in the southern Sierra Nevada, east of Visalia, California, in the United States of America. It was established on September 25th, 1890. The park spans 404,051 acres (1,635 km2). Encompassing a vertical relief of nearly 13,000 feet (4,000 m), the park contains among its natural resources the highest point in the contiguous 48 United States, Mount Whitney, at 14,505 feet (4,421 m) above sea level. The park is south of and contiguous with Kings Canyon National Park; the two are administered by the National Park Service together.

The park is famous for its Giant Sequoia trees, including the General Sherman tree, the largest tree on Earth. The General Sherman tree grows in the Giant Forest, which contains five out of the ten largest trees in the world, in terms of wood volume. The Giant Forest is connected by the park's Generals Highway to Kings Canyon National Park's Grant Grove, home to the General Grant tree among other sequoias. The park's Giant Sequoia forests are part of 202,430 acres (81,921 ha) of old-growth forests shared by Sequoia and Kings Canyon National Parks. Indeed, the parks preserve a landscape that still resembles the southern Sierra Nevada before Euro-American settlement.

Front country

Many park visitors enter Sequoia National Park through its southern entrance near the town of Three Rivers at Ash Mountain at 1,700 ft (520 m) elevation. The lower elevations around Ash Mountain contain the only National Park Service-protected California Foothills ecosystem, consisting of blue oak woodlands, foothills chaparral, grasslands, yucca plants, and steep, mild river valleys. The foothills region is also home to abundant wildlife: bobcats, foxes, ground squirrels, rattlesnakes, and mule deer are commonly seen in this area, and more rarely, reclusive mountain lions are seen as well. The California Black Oak, Quercus kelloggii, is a key transition species between the chaparral and higher elevation conifer forest.

At higher elevations in the front country, between 5,500 and 9,000 feet (1,700 and 2,700 m) in elevation, the landscape becomes montane forest-dominated coniferous belt. Found here are Ponderosa, Jeffrey, Sugar, and Lodgepole pine trees, as well as abundant white and red fir. Found here too are the mighty Sequoia trees, the most massive living trees on earth. Between the trees, spring and summer snowmelts sometimes fan out to form lush, though delicate, meadows. In this region, visitors often see mule deer, Douglas squirrel, and American black bears, who have been known to break into unattended cars to steal food left by careless visitors.

Back country

The vast majority of the park is roadless wilderness; in fact, to the surprise of many visitors, no road crosses the Sierra Nevada within the park's boundaries. 84% of Sequoia and Kings Canyon National Parks is designated as Wilderness and is accessible only by foot or by horse.

Sequoia's backcountry offers a vast expanse of high-alpine wonders. Covering the highest-elevation region of the High Sierra, the backcountry includes Mount Whitney on the eastern border of the park, accessible from the Giant Forest via the High Sierra Trail. On a traveler's path along this 35-mile (56 km) backcountry trail, one passes through about 10 miles (16 km) of montane forest before reaching the backcountry resort of Bearpaw Meadow, just short of the Great Western Divide. Bearpaw Meadow offers rustic tent cabins and gourmet meals cooked by a seasonal resident park crew.

Continuing along the High Sierra Trail over the Great Western Divide via Kaweah Gap, one passes from the Kaweah River Drainage, with its characteristic V-shaped river valleys, and into the Kern River drainage, where an ancient fault line has aided glaciers in the last ice age to create a U-shaped canyon that is almost perfectly straight for nearly 20 miles (32 km). On the floor of this canyon, at least 2 days hike from the nearest road, is the Kern Canyon hot spring, a popular resting point for weary backpackers. From the floor of Kern Canyon, the trail ascends again over 8,000 ft (2,400 m) to the summit of Mount Whitney.

At Mount Whitney, the High Sierra Trail meets with the John Muir Trail and the epic Pacific Crest Trail, which continue northward along the Sierra crest and into the backcountry of Kings Canyon National Park.

Park attractions

In addition to hiking, camping, fishing, and backpacking, the following attractions are highlights with many park visitors:

*Tunnel Log is a tunnel cut through a fallen giant sequoia tree in Sequoia National Park in California. The tree, which measured 275 feet (84 m) tall and 21 feet (6.4 m) in diameter, fell across a park road in 1937 due to natural causes. The following year, a crew cut an 8-foot (2.4 m) tall, 17-foot (5.2 m) wide tunnel through the trunk, making the road passable again.

*Crescent Meadow is a small, sequoia-rimmed meadow in the Giant Forest region of Sequoia National Park. This sierran montane meadow marks the western terminus of the High Sierra Trail, which stretches from the meadow across the Great Western Divide to Mount Whitney. Pioneer Hale Tharp homesteaded in this and nearby Log Meadow. Conservationist John Muir visited this meadow many times and praised it highly calling it the "Gem of the Sierras". The meadow lies at the end of a three mile paved road which leaves the Generals Highway near the Giant Forest Museum.

*Moro Rock is a granite dome located in the center of the park, at the head of Moro Creek, between Giant Forest and Crescent Meadow. A 400-step stairway, built in the 1930s by the Civilian Conservation Corps, is cut into and poured onto the rock, so that visitors can hike to the top. The stairway is listed on the National Register of Historic Places. The view from the rock encompasses much of the Park, including the Great Western Divide. It has an elevation of 6,725 feet (2,050 m).

*Campgrounds in the park include three in the foothills area: Potwisha (42 sites), Buckeye Flat (28 sites), and South Fork (10 sites). Four campgrounds are at higher, conifer-dominated elevations, ranging from 6,650 to 7,500 feet (2,000 to 2,300 m): Atwell Mill (21 sites), Cold Springs (40 sites), Lodgepole (214 sites), and Dorst (204 sites).

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Glass House Mountains National Park is a national park in Queensland (Australia), 70 km (43 mi) northeast of Brisbane. It consists of a flat plain punctuated by volcanic plugs, the cores of extinct volcanoes that formed 27 million to 26 million years ago. The mountains would once have had pyroclastic exteriors, but these have eroded away.

Origin of name

The Glass House Mountains were named by Captain James Cook as he sailed north up the coast of what is now Queensland in 1770 as part of his epic voyage aboard his ship HM Bark Endeavour. They were so called as the shape of the mountains reminded him of the huge glass furnaces (glasshouses) back in his native Yorkshire.

Mount Beerwah is the highest peak within the park at 555 m (1,821 ft). Mount Coonowrin 377 metres is the second highest and Mount Tibrogargan at 364 m (1,194 ft) is the third highest. Walking tracks normally allow access to the summits of Mount Beerwah and Mount Tibrogargan (although Mount Beerwah summit track is closed as of April 2009), however climbing Mount Coonowrin is prohibited due to the danger of rock falls.

Flora

The peaks support a diverse range of habitats including montane heath and shrubland, open forest and woodlands and small rainforest patches on some peaks. The montane heath is particularly rich in threatened and endemic species many of which can be found nowhere else on earth. The Glasshouse Mountains Tea Tree Leptospermum leuhmanii is restricted to the peaks and is notable for its beautiful smooth orange bark. The Mount Beerwah Mallee Red Gum Eucalyptus kabiana is also endemic and is named after the local Aboriginal Tribe and traditional owners the Kabi Kabi (pronounced Gubbi Gubbi). Other endemic plants include Gonocarpus effusus, Grevillea hodgei, Westringia grandifolia and Leptospermum oreophyllum.

Aboriginal legend

In the Aboriginal legend the mountains are members of a family with the father being Mount Tibrogargan and the mother Mount Beerwah. All of the other mountains are sons and daughters with the eldest being Mount Coonowrin.

Tibrogargan, the father, observes that the sea is rising and asks that Coonowrin the eldest son help their pregnant mother to safety. Terrified, Coonowrin instead flees. Infuriated by his sons cowardice Tibrogargan pursues him and strikes him so hard that he dislocates Coonowrin's neck.

Once the danger passes Coonowrin feels tremendous guilt for his actions and asks his father, brothers and sisters for forgiveness but all wept with shame. This is said to explain the many small streams that flow through the area. Tibrogargan turned his back on Coonowrin and gazes out to sea refusing to look at his son Coonowrin who continues to hang his head in shame and weeps.

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Torres del Paine National Park is a national park encompassing a mountains, glacier, lake, and river-rich areas in southern Chilean Patagonia. The Cordillera del Paine is the centerpiece of the park. It lies in a transition area between the Magellanic subpolar forests and the Patagonian Steppes. The park is located 112 km (70 mi) north of Puerto Natales and 312 km (194 mi) north of Punta Arenas. Bernardo O'Higgins National Park is its neighbour to the west, while Los Glaciares National Park is located to the north in Argentine territory.

History

Lady Florence Dixie, in her book published in 1880, gives one of the first descriptions of the area and refers to the three towers as Cleopatra's Needles. She and her party were the first tourists to visit what is now called Torres del Paine National Park.

Several European scientists and explorers visited the area in the following decades, including Otto Nordenskiöld, Carl Skottsberg and Alberto María de Agostini.

Gunther Plüschow was the first person to fly over the Paine massif.

The park was established in 1959 as Parque Nacional de Turismo Lago Grey (Grey Lake National Tourism Park) and it was given its present name in 1970. In 1977, Guido Monzino donated 12,000 hectares (30,000 acres) to the Chilean Government, and its definitive limits were established. The park was designated a World Biosphere Reserve by UNESCO in 1978.

Geography

The landscape of the park is dominated by the Paine massif, which is an eastern spur of the Andes located on the east side of the Grey Glacier, rising dramatically above the Patagonian steppe. Small valleys separate the spectacular granite spires and mountains of the massif. These are: Valle del Francés (French Valley), Valle Bader, Valle Ascencio, and Valle del Silencio (Silence Valley).

The head of French Valley is a cirque formed by impressive cliffs. To west rise abruptly the colossal walls of Cerro Cota 2000 and Cerro Catedral. Cerro Cota 2000 is named for its elevation; its highest contour line is about 2,000 m (6,562 ft). Cerro Catedral is named so because its east face resembles a cathedral's facade. To the north stands the granite arête called Aleta de Tiburón (English: Shark's Fin). To the east, from north to south, lie the peaks Fortaleza (Fortress), La Espada (The Sword), La Hoja (The Blade), La Máscara (The Mummer), Cuerno Norte (North Horn), and Cuerno Principal (Main Horn).

Silence Valley is where standing face to face the gigantic granite walls of Cerro Fortaleza and Cerro Escudo (Shield Hill) with the western faces of the Torres del Paine. Ascencio Valley is the normal route to reach the Torres del Paine lookout, which is located at the bank of a milky green tarn. The highest mountain of the group is Paine Grande, although its elevation has not been determined with precision.

The Southern Patagonian Ice Field mantles a great portion of the park. Glaciers include the Dickson, the Grey, and the Tyndall.

Among the lakes are the Dickson Lake, Nordenskjöld Lake, Pehoe Lake, Grey Lake, Sarmiento Lake, and Del Toro Lake. Only a portion of the latter is within the borders of the park. All are vividly colored, most due to rock flour suspended in their waters. The main river flowing through the park is Paine River. Most of the rivers and lakes of the park drain into Última Esperanza Sound via Serrano River.

Geology

Much of the geology of the Paine Massif area consists of Cretaceous sedimentary rocks that have been intruded by a Miocene-aged laccolith. Orogenic and erosional processes have shaped the present-day topography, glacial erosion being the main one responsible for the sculpturing of the massif in the last tens of thousands of years. A good example of the latter are the Cuernos del Paine, whose central bands of exposed granite strongly contrast with the dark aspect of their tops, which are remnants of a heavily eroded sedimentary stratum. In the case of Las Torres, what once was their overlying sedimentary rock layer has been completely eroded away, leaving behind the more resistant granite.

Flora

Torres del Paine National Park is adorned with beautiful vegetation. Among them are the evergreen Embothrium coccineum, which produces vivid red flowers grouped in corymbs and the Calceolaria uniflora, of striking shape and colors. The park has 7 documented species of Orchidaceae, including the Chloraea magellanica.

In the park have been recorded 85 non-native plant species, of which 75 are of European origin and 31 are considered to be invasive.

The park contains four vegetation zones: Patagonian steppe, Pre-Andean shrubland, Magellanic deciduous forest and Andean Desert. The vegetation of the Patagonian steppe is dominated by Fescue species (mainly Festuca gracillima), which are resistant to harsh winds and weather conditions that are typical of the Patagonian region. Some of the dominant plant species of the Pre-Andeanthisst shrubland are the Mulinum spinosum (a cushion plant) and Escallonia rubra, which are frequently associated with other species, including Anathrophyllun desideratum and Berberis buxifolia. The Magellanic deciduous forest is home to various species of trees such as the Nothofagus pumilio and Nothofagus antarctica. Above tree line in the Andean Desert, Escallonia rubra, Empetrum rubrum and Senecio skottsbergii take the place of Nothofagus pumilio trees.

Fauna

Guanacos are one of the most common mammals found in the park. Other mammals include cougars and foxes. It is also home to the endangered Chilean Huemul.

The park contains breeding populations of 15 bird of prey species. and two others are likely reproducing here. Among them are Andean Condor, Black-chested Buzzard-eagle, Rufous-tailed Hawk, Cinereous Harrier, Chimango Caracara, Magellanic Horned Owl, Austral Pygmy-owl, to name but a few. Other birds occurring in the park include the Chilean Flamingo, Darwin's Rhea, Coscoroba Swan, Black-necked Swan, Magellanic Woodpecker, Magellan Goose and Black-faced Ibis.

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Parque Nacional Los Glaciares (Spanish: The Glaciers) is a national park in the Santa Cruz Province, in Argentine Patagonia. It comprises an area of 4459 km². In 1981 it was declared a World Heritage Site by UNESCO.

The national park, created in 1937, is the second largest in Argentina. Its name refers to the giant ice cap in the Andes range that feeds 47 large glaciers, of which only 13 flow towards the Atlantic Ocean. The ice cap is the largest outside of Antarctica and Greenland. In other parts of the world, glaciers start at a height of at least 2,500 meters above mean sea level, but due to the size of the ice cap, these glaciers begin at only 1,500m, sliding down to 200m AMSL, eroding the surface of the mountains that support them.

Geography

Los Glaciares, of which 30% is covered by ice, can be divided in two parts, each corresponding with one of the two elongated big lakes partially contained by the Park. Lake Argentino, 1,466 km² and the largest in Argentina, is in the south, while Lake Viedma, 1,100 km², is in the north. Both lakes feed the Santa Cruz River that flows down to Puerto Santa Cruz on the Atlantic. Between the two halves is a non-touristic zone without lakes called Zona Centro.

The northern half consists of part of Viedma Lake, the Viedma Glacier and a few minor glaciers, and a number of mountains very popular among fans of climbing and trekking, including Mount Fitz Roy and Cerro Torre.

The southern part has, as well as a number of smaller ones, the major glaciers which flow into Lake Argentino: Perito Moreno Glacier, Upsala Glacier, and Spegazzini Glacier. Typical excursion boats travel between icebergs to visit Bahía Onelli, and the otherwise inaccessible Spegazzini and Upsala. The Perito Moreno is reachable by land.

Ecology

The mountains hold most of the humidity from the Pacific Ocean, letting through only the ice coldness (annual average of 7.5 °C) and creating an arid steppe on the Argentine side of the range. This area is habitat for ñandúes, guanaco, cougar, and gray fox, the latter who has suffered from the invasion of the cattle industry and are endangered. The guanaco, while not endangered, has had a dramatic decline in historic population due to large scale grazing of livestock throughout much of Patagonia. There are over 1000 species of birds in the area (condors, eagles, and others), but only 100 have been registered. Between the ice and the Patagonian steppe there is a fertile area of forests composed mainly of lengas and guindos, but also ñires. Within these more hospitable areas also live huemul deer and Torrent Duck.

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Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, though it also extends into Montana and Idaho. Yellowstone was the first national park in the world, and is known for its wildlife and its many geothermal features, especially Old Faithful Geyser, one of the most popular features in the park. It has many types of ecosystems, but the subalpine forest is dominant.

Native Americans have lived in the Yellowstone region for at least 11,000 years. The region was bypassed during the Lewis and Clark Expedition in the early 1800s. Aside from visits by mountain men during the early to mid-1800s, organized exploration did not begin until the late 1860s. The U.S. Army was commissioned to oversee the park just after its establishment. In 1917, administration of the park was transferred to the National Park Service, which had been created the previous year. Hundreds of structures have been built and are protected for their architectural and historical significance, and researchers have examined more than 1,000 archaeological sites.

Yellowstone National Park spans an area of 3,468 square miles (8,980 km2), comprising lakes, canyons, rivers and mountain ranges. Yellowstone Lake is one of the largest high-altitude lakes in North America and is centered over the Yellowstone Caldera, the largest supervolcano on the continent. The caldera is considered an active volcano; it has erupted with tremendous force several times in the last two million years. Half of the world's geothermal features are in Yellowstone, fueled by this ongoing volcanism. Lava flows and rocks from volcanic eruptions cover most of the land area of Yellowstone. The park is the centerpiece of the Greater Yellowstone Ecosystem, the largest remaining, nearly intact ecosystem in the Earth's northern temperate zone.

Hundreds of species of mammals, birds, fish and reptiles have been documented, including several that are either endangered or threatened. The vast forests and grasslands also include unique species of plants. Grizzly Bears, wolves, and free-ranging herds of bison and elk live in the park. Forest fires occur in the park each year; in the large forest fires of 1988, nearly one third of the park burned. Yellowstone has numerous recreational opportunities, including hiking, camping, boating, fishing and sightseeing. Paved roads provide close access to the major geothermal areas as well as some of the lakes and waterfalls. During the winter, visitors often access the park by way of guided tours that use either snow coaches or snowmobile.

Geography

Approximately 96 percent of the land area of Yellowstone National Park is located within the state of Wyoming. Another 3 percent is within Montana, with the remaining 1 percent in Idaho. The park is 63 miles (101 km) north to south, and 54 miles (87 km) west to east by air. Yellowstone is 2,219,789 acres (898,317 ha; 3,468.420 sq mi) in area, larger than the states of Rhode Island or Delaware. Rivers and lakes cover 5 percent of the land area, with the largest water body being Yellowstone Lake at 87,040 acres (35,220 ha; 136.00 sq mi). Yellowstone Lake is up to 400 feet (120 m) deep and has 110 miles (180 km) of shoreline. At an elevation of 7,733 feet (2,357 m) above sea level, Yellowstone Lake is the largest high altitude lake in North America. Forests comprise 80 percent of the land area of the park; most of the rest is grassland.

The Continental Divide of North America runs diagonally through the southwestern part of the park. The divide is a topographic feature that separates Pacific Ocean and Atlantic Ocean water drainages. About one third of the park lies on the west side of the divide. The origins of the Yellowstone and Snake Rivers are near each other but on opposite sides of the divide. As a result, the waters of the Snake River flow to the Pacific Ocean, while those of the Yellowstone find their way to the Atlantic Ocean via the Gulf of Mexico.

The park sits on the Yellowstone Plateau, at an average elevation of 8,000 feet (2,400 m) above sea level. The plateau is bounded on nearly all sides by mountain ranges of the Middle Rocky Mountains, which range from 9,000 to 11,000 feet (2,700 to 3,400 m) in elevation. The highest point in the park is atop Eagle Peak (11,358 ft/3,462 m) and the lowest is along Reese Creek (5,282 ft/1,610 m). Nearby mountain ranges include the Gallatin Range to the northwest, the Beartooth Mountains in the north, the Absaroka Range to the east, and the Teton Range and the Madison Range to the southwest and west. The most prominent summit on the Yellowstone Plateau is Mount Washburn at 10,243 feet (3,122 m).

Yellowstone National Park has one of the world's largest petrified forests, trees which were long ago buried by ash and soil and transformed from wood to mineral materials. This ash and other volcanic debris, are believed to have come from the park area itself. This is largely due to the fact that Yellowstone is actually a massive caldera of a supervolcano. There are 290 waterfalls of at least 15 feet (4.6 m) in the park, the highest being the Lower Falls of the Yellowstone River at 308 feet (94 m).

Three deep canyons are located in the park, cut through the volcanic tuff of the Yellowstone Plateau by rivers over the last 640,000 years. The Lewis River flows through Lewis Canyon in the south, and the Yellowstone River has carved two colorful canyons, the Grand Canyon of the Yellowstone and the Black Canyon of the Yellowstone in its journey north.

Geology

Yellowstone is at the northeastern end of the Snake River Plain, a great U-shaped arc through the mountains that extends from Boise, Idaho some 400 miles (640 km) to the west. This feature traces the route of the North American Plate over the last 17 million years as it was transported by plate tectonics across a stationary mantle hotspot. The landscape of present-day Yellowstone National Park is the most recent manifestation of this hotspot below the crust of the Earth.

The Yellowstone Caldera is the largest volcanic system in North America. It has been termed a "supervolcano" because the caldera was formed by exceptionally large explosive eruptions. The current caldera was created by a cataclysmic eruption that occurred 640,000 years ago, which released 240 cubic miles (1,000 km³) of ash, rock and pyroclastic materials. This eruption was 1,000 times larger than the 1980 eruption of Mount St. Helens. It produced a crater nearly a two thirds of a mile (1 km) deep and 52 by 28 miles (84 by 45 km) in area and deposited the Lava Creek Tuff, a welded tuff geologic formation. The most violent known eruption, which occurred 2.1 million years ago, ejected 588 cubic miles (2,450 km³) of volcanic material and created the rock formation known as the Huckleberry Ridge Tuff and created the Island Park Caldera.

A smaller eruption ejected 67 cubic miles (280 km³) of material 1.2 million years ago, forming the Henry's Fork Caldera and depositing the Mesa Falls Tuff.

Each of the three climax eruptions released vast amounts of ash that blanketed much of central North America falling many hundreds of miles away. The amount of ash and gases released into the atmosphere probably caused significant impacts to world weather patterns and led to the extinction of many species, primarily in North America.

A subsequent minor climax eruption occurred 160,000 years ago. It formed the relatively small caldera that contains the West Thumb of Yellowstone Lake. Later, two smaller eruptive cycles, the last one ending about 70,000 years ago, buried much of the caldera under thick lava flows.

Each eruption is in fact a part of an eruptive cycle that climaxes with the collapse of the roof of a partially emptied magma chamber. This creates a crater, called a caldera, and releases vast amounts of volcanic material, usually through fissures that ring the caldera. The time between the last three cataclysmic eruptions in the Yellowstone area has ranged from 600,000 to 900,000 years, but the small number of such climax eruptions cannot be used to make an accurate prediction for future volcanic events.

Between 630,000 and 700,000 years ago, Yellowstone Caldera was nearly filled in with periodic eruptions of rhyolitic lavas such as those that can be seen at Obsidian Cliffs and basaltic lavas which can be viewed at Sheepeater Cliff. Lava strata are most easily seen at the Grand Canyon of the Yellowstone, where the Yellowstone River continues to carve into the ancient lava flows. The canyon is a classic V-shaped valley, indicative of river-type erosion rather than erosion caused by glaciation.

The most famous geyser in the park, and perhaps the world, is Old Faithful Geyser, located in Upper Geyser Basin. Castle Geyser, Lion Geyser and Beehive Geyser are in the same basin. The park contains the largest active geyser in the world—Steamboat Geyser in the Norris Geyser Basin. There are 300 geysers in Yellowstone and a total of at least 10,000 geothermal features altogether. Half the geothermal features and two-thirds of the world's geysers are concentrated in Yellowstone.

In May 2001, the U.S. Geological Survey, Yellowstone National Park, and the University of Utah created the Yellowstone Volcano Observatory (YVO), a partnership for long-term monitoring of the geological processes of the Yellowstone Plateau volcanic field, for disseminating information concerning the potential hazards of this geologically active region.

In 2003, changes at the Norris Geyser Basin resulted in the temporary closure of some trails in the basin. New fumaroles were observed, and several geysers showed enhanced activity and increasing water temperatures. Several geysers became so hot that they were transformed into purely steaming features; the water had become superheated and they could no longer erupt normally. This coincided with the release of reports of a multiple year United States Geological Survey research project which mapped the bottom of Yellowstone Lake and identified a structural dome that had uplifted at some time in the past. Research indicated that these uplifts posed no immediate threat of a volcanic eruption, since they may have developed long ago, and there had been no temperature increase found near the uplifts. On March 10, 2004, a biologist discovered 5 dead bison which apparently had inhaled toxic geothermal gases trapped in the Norris Geyser Basin by a seasonal atmospheric inversion. This was closely followed by an upsurge of earthquake activity in April 2004. In 2006, it was reported that the Mallard Lake Dome and the Sour Creek Dome— areas that have long been known to show significant changes in their ground movement— had risen at a rate of 1.5 to 2.4 inches (3.8 to 6.1 cm) per year from mid–2004 through 2006. As of late 2007, the uplift has continued at a reduced rate. These events inspired a great deal of media attention and speculation about the geologic future of the region. Experts responded to the conjecture by informing the public that there was no increased risk of a volcanic eruption in the near future.

Yellowstone experiences thousands of small earthquakes every year, virtually all of which are undetectable to people. There have been six earthquakes with at least magnitude 6 or greater in historical times, including a 7.5 magnitude quake that struck just outside the northwest boundary of the park in 1959. This quake triggered a huge landslide, which caused a partial dam collapse on Hebgen Lake; immediately downstream, the sediment from the landslide dammed the river and created a new lake, known as Earthquake Lake. Twenty-eight people were killed, and property damage was extensive in the immediate region. The earthquake caused some geysers in the northwestern section of the park to erupt, large cracks in the ground formed and emitted steam, and some hot springs' normally clear water turned muddy. A 6.1 magnitude earthquake struck inside the park on June 30, 1975, but damage was minimal. For three months in 1985, 3,000 minor earthquakes were detected in the northwestern section of the park, during what has been referred to as an earthquake swarm, and has been attributed to minor subsidence of the Yellowstone caldera. Beginning on April 30, 2007, sixteen small earthquakes with magnitudes up to 2.7 occurred in the Yellowstone Caldera for several days. These swarms of earthquakes are common, and there have been 70 such swarms between 1983 and 2008. In December 2008, over 250 earthquakes were measured over a four day span under Yellowstone Lake, the largest measuring a magnitude of 3.9. In January 2010, more than 250 earthquakes were detected over a two day period. Seismic activity in Yellowstone National Park continues and is reported hourly by the Earthquake Hazards Program of the U.S. Geological Survey.

Biology and ecology

Yellowstone National Park is the centerpiece of the 20 million acre/31,250 square-mile (8,093,712 ha/80,937 km2) Greater Yellowstone Ecosystem, a region that includes Grand Teton National Park, adjacent National Forests and expansive wilderness areas in those forests. The ecosystem is the largest remaining continuous stretch of mostly undeveloped pristine land in the continental United States,considered to be the world's largest intact ecosystem in the northern temperate zone (although the area is mostly not temperate but subalpine, and all the national forest lands surrounding the National Park are not intact). With the successful wolf reintroduction program, which began in the 1990s, virtually all the original faunal species known to inhabit the region when white explorers first entered the area can still be found there.

Climate

Yellowstone climate is greatly influenced by altitude, with lower elevations generally found to be warmer year round. The record high temperature was 99 °F (37 °C) in 2002, while the coldest temperature recorded is −66 °F (−54.4 °C) in 1933. During the summer months of June through early September, daytime highs are normally in the 70 to 80 °F (21 to 27 °C) range, while nighttime lows can go to below freezing (0 °C)—especially at higher altitudes. Summer afternoons are frequently accompanied by thunderstorms. Spring and fall temperatures range between 30 and 60 °F (-1 and 16 °C) with cold nights in the teens to single digits (-5 to -20 °C). Winter in Yellowstone is very cold with high temperatures usually between zero to 20 °F (-20 to -5 °C) and nighttime temperatures below zero °F (-20 °C) for most of the winter.

Precipitation in Yellowstone is highly variable and ranges from 15 inches (380 mm) annually near Mammoth Hot Springs, to 80 inches (2,000 mm) in the southwestern sections of the park. The precipitation of Yellowstone is greatly influenced by the moisture channel formed by the Snake River Plain to the west that was, in turn, formed by Yellowstone itself. Snow is possible in any month of the year, with averages of 150 inches (3,800 mm) annually around Yellowstone Lake, to twice that amount at higher elevations.

Tornadoes in Yellowstone are rare; however, on July 21, 1987, the most powerful tornado recorded in Wyoming touched down in the Teton Wilderness of Bridger-Teton National Forest and hit Yellowstone National Park. Called the Teton–Yellowstone tornado, it was classified as an F4, with wind speeds estimated at between 207 and 260 miles per hour (333 and 420 km/h). The tornado left a path of destruction 1 to 2 miles (1.6 to 3.2 km) wide, and 24 miles (39 km) long, and leveled 15,000 acres (6,100 ha; 23 sq mi) of mature pine forest.

credited to wikipedia