In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation include drizzle, sleet, snow and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and "precipitates", thus and mist are not precipitation but suspensions, because the water vapor does not condense sufficiently to precipitate. Two processes acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called "showers."Moisture, lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condensed into clouds and rain. This process is active when freezing rain occurs. A stationary front is present near the area of freezing rain and serves as the foci for forcing and rising air.
Provided necessary and sufficient atmospheric moisture content, the moisture within the rising air will condense into clouds, namely stratus and cumulonimbus. The cloud droplets will grow large enough to form raindrops and descend toward the Earth where they will freeze on contact with exposed objects. Where warm water bodies are present, for example due to water evaporation from lakes, lake-effect snowfall becomes a concern downwind of the warm lakes within the cold cyclonic flow around the backside of extratropical cyclones. Lake-effect snowfall can be locally heavy. Thundersnow is possible within lake effect precipitation bands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation. On the leeward side of mountains, desert climates can exist due to the dry air caused by compressional heating. Most precipitation is caused by convection; the movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes.
Precipitation is a major component of the water cycle, is responsible for depositing the fresh water on the planet. 505,000 cubic kilometres of water falls as precipitation each year. Given the Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres, but over land it is only 715 millimetres. Climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes. Precipitation may occur on other celestial bodies, e.g. when it gets cold, Mars has precipitation which most takes the form of frost, rather than rain or snow. Precipitation is a major component of the water cycle, is responsible for depositing most of the fresh water on the planet. 505,000 km3 of water falls as precipitation each year, 398,000 km3 of it over the oceans. Given the Earth's surface area, that means the globally averaged annual precipitation is 990 millimetres. Mechanisms of producing precipitation include convective and orographic rainfall.
Convective processes involve strong vertical motions that can cause the overturning of the atmosphere in that location within an hour and cause heavy precipitation, while stratiform processes involve weaker upward motions and less intense precipitation. Precipitation can be divided into three categories, based on whether it falls as liquid water, liquid water that freezes on contact with the surface, or ice. Mixtures of different types of precipitation, including types in different categories, can fall simultaneously. Liquid forms of precipitation include drizzle. Rain or drizzle that freezes on contact within a subfreezing air mass is called "freezing rain" or "freezing drizzle". Frozen forms of precipitation include snow, ice needles, ice pellets and graupel; the dew point is the temperature to which a parcel must be cooled in order to become saturated, condenses to water. Water vapor begins to condense on condensation nuclei such as dust and salt in order to form clouds. An elevated portion of a frontal zone forces broad areas of lift, which form clouds decks such as altostratus or cirrostratus.
Stratus is a stable cloud deck which tends to form when a cool, stable air mass is trapped underneath a warm air mass. It can form due to the lifting of advection fog during breezy conditions. There are four main mechanisms for cooling the air to its dew point: adiabatic cooling, conductive cooling, radiational cooling, evaporative cooling. Adiabatic cooling occurs when air expands; the air can rise due to convection, large-scale atmospheric motions, or a physical barrier such as a mountain. Conductive cooling occurs when the air comes into contact with a colder surface by being blown from one surface to another, for example from a liquid water surface to colder land. Radiational cooling occurs due to the emission of infrared radiation, either by the air or by the surface underneath. Evaporative cooling occurs when moisture is added to the air through evaporation, which forces the air temperature to cool to its wet-bulb temperature, or until it reaches saturation; the main ways water vapor is added to the air are: wind convergence into areas of upward motion, precipitation or virga falling from above, daytime heating evaporating water from the surface of oceans, water bodies or wet lan
Sierra Negra is an extinct volcano located in the Mexican state of Puebla, close to the border with Veracruz. At 4,580 metres above sea level, it is the fifth-highest peak in Mexico. However, because it is overshadowed by nearby Pico de Orizaba, it is not too well known and left out of lists of Mexico's mountains. Sierra Negra is located within the Pico de Orizaba National Park; the mountain is the site for two of the world's premier astronomical instruments, the Large Millimeter Telescope and the High Altitude Water Cherenkov Observatory. Therefore, the access to the mountain is restricted and has to be applied for at least a week in advance; the service road for this facility is claimed to be the highest road in North America. A part of the telescope facility is visible as a white dot in the first picture below and more in the second picture; the Spanish word sierra is applied to mountain ranges or ridges. However, a few mountains were given the name sierra after the Conquest, like Sierra de Tlaxcala or Sierra de Tolocan.
As listed by the Mexican geographical institute INEGI, the official name for the Sierra Negra is Cerro La Negra, although the latter is unused in common speech. The Nahuatl names Tliltépetl or Atlitzin are sometimes attached. Speakers of Orizaba Nahuatl called the mountain Iztactepetl Icni; the mountain range to the east of the city of Tehuacán, with such principal towns as Zoquitlán and Coyomeapan, is known as the "Sierra Negra". List of mountain peaks of Mexico List of the highest major summits of North America Trans-Mexican Volcanic Belt National Institute of Astrophysics and Electronics List of national parks of Mexico "Sierra Negra". SummitPost.org. Retrieved 2016-10-16; the Large Millimeter Telescope Peakbagger.com: Sierra Negra "Pico de Orizaba". Global Volcanism Program. Smithsonian Institution. Yarza de la Torre, Esperanza. Volcanes de México. Aguilar. P. 237 pp
For the mountain in Antarctica, see Mount Steele. Mount Steele is the fifth-highest mountain in Canada and the eleventh-highest peak in North America reaching the height of 5,073 metres. A lower southeast peak of Mt. Steele stands at 4,300 m, it was named after Sir Sam Steele, the North-West Mounted Police officer in charge of the force in the Yukon during the Klondike Gold Rush. Walter A. Wood led a team consisting of Foresta Wood, Swiss guide Hans Fuhrer, Joseph W. Fobes, Harrison Wood and I. Pearce Hazard; the expedition approached the peak on the eastern side from Kluane Lake. Base camp was established at the foot of the Steele Glacier with horses carrying loads to Advance Base Camp further along the glacier. ABC provided good views of the mountain and the team decided on the east ridge as their line of ascent. After waiting for the weather to improve after heavy snowfalls, a four-man team consisting of Walter Wood, Harrison Wood and Forbes left Camp 8 at the base of the ridge, their plan to was to make a 2,440-meter push to the summit.
After steady upwards progress, deteriorating weather forced them to return to Camp 8 where they waited out a five-day storm which dumped over a metre of fresh snow. They started out again on August 15 and the ascent was made easier this time by windblown and hard steep snow slopes rather than steep soft snow on their earlier attempt. At 4,570 m, a plateau of wretched snow forced the team to crawl on all fours. Walter Wood commented: The humour of it impressed me. Here were four normal human beings crawling across a snow field 15,000 ft. up in the air, engaged in what they fondly believed to be a sporting venue. Alternating the lead every 100 paces, they made their way from the plateau to the top reaching the summit at 2:30 pm; the team enjoyed a blissful thirty minutes of windless conditions on top before beginning their descent. List of mountain peaks of North America List of mountain peaks of Canada
Mexico the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States. Covering 2,000,000 square kilometres, the nation is the fifth largest country in the Americas by total area and the 13th largest independent state in the world. With an estimated population of over 120 million people, the country is the eleventh most populous state and the most populous Spanish-speaking state in the world, while being the second most populous nation in Latin America after Brazil. Mexico is a federation comprising 31 states and Mexico City, a special federal entity, the capital city and its most populous city. Other metropolises in the state include Guadalajara, Puebla, Tijuana and León. Pre-Columbian Mexico dates to about 8000 BC and is identified as one of five cradles of civilization and was home to many advanced Mesoamerican civilizations such as the Olmec, Teotihuacan, Zapotec and Aztec before first contact with Europeans. In 1521, the Spanish Empire conquered and colonized the territory from its politically powerful base in Mexico-Tenochtitlan, administered as the viceroyalty of New Spain.
Three centuries the territory became a nation state following its recognition in 1821 after the Mexican War of Independence. The post-independence period was tumultuous, characterized by economic inequality and many contrasting political changes; the Mexican–American War led to a territorial cession of the extant northern territories to the United States. The Pastry War, the Franco-Mexican War, a civil war, two empires, the Porfiriato occurred in the 19th century; the Porfiriato was ended by the start of the Mexican Revolution in 1910, which culminated with the promulgation of the 1917 Constitution and the emergence of the country's current political system as a federal, democratic republic. Mexico has the 11th largest by purchasing power parity; the Mexican economy is linked to those of its 1994 North American Free Trade Agreement partners the United States. In 1994, Mexico became the first Latin American member of the Organisation for Economic Co-operation and Development, it is classified as an upper-middle income country by the World Bank and a newly industrialized country by several analysts.
The country is considered both a regional power and a middle power, is identified as an emerging global power. Due to its rich culture and history, Mexico ranks first in the Americas and seventh in the world for number of UNESCO World Heritage Sites. Mexico is an ecologically megadiverse country, ranking fourth in the world for its biodiversity. Mexico receives a huge number of tourists every year: in 2018, it was the sixth most-visited country in the world, with 39 million international arrivals. Mexico is a member of the United Nations, the World Trade Organization, the G8+5, the G20, the Uniting for Consensus group of the UN, the Pacific Alliance trade bloc. Mēxihco is the Nahuatl term for the heartland of the Aztec Empire, namely the Valley of Mexico and surrounding territories, with its people being known as the Mexica, it is believed to be a toponym for the valley which became the primary ethnonym for the Aztec Triple Alliance as a result, although it could have been the other way around.
In the colonial era, back when Mexico was called New Spain this territory became the Intendency of Mexico and after New Spain achieved independence from the Spanish Empire it came to be known as the State of Mexico with the new country being named after its capital: the City of Mexico, which itself was founded in 1524 on top of the ancient Mexica capital of Mexico-Tenochtitlan. Traditionally, the name Tenochtitlan was thought to come from Nahuatl tetl and nōchtli and is thought to mean "Among the prickly pears rocks". However, one attestation in the late 16th-century manuscript known as "the Bancroft dialogues" suggests the second vowel was short, so that the true etymology remains uncertain; the suffix -co is the Nahuatl locative, making the word a place name. Beyond that, the etymology is uncertain, it has been suggested that it is derived from Mextli or Mēxihtli, a secret name for the god of war and patron of the Mexica, Huitzilopochtli, in which case Mēxihco means "place where Huitzilopochtli lives".
Another hypothesis suggests that Mēxihco derives from a portmanteau of the Nahuatl words for "moon" and navel. This meaning might refer to Tenochtitlan's position in the middle of Lake Texcoco; the system of interconnected lakes, of which Texcoco formed the center, had the form of a rabbit, which the Mesoamericans pareidolically associated with the moon rabbit. Still another hypothesis suggests that the word is derived from Mēctli, the name of the goddess of maguey; the name of the city-state was transliterated to Spanish as México with the phonetic value of the letter x in Medieval Spanish, which represented the voiceless postalveolar fricative. This sound, as well as the voiced postalveolar fricative, represented by a j, evolved into a voiceless velar fricative during the 16th century; this led to the use of the variant Méjico in many publications in Spanish, most notably in Spain, whereas in Mexico and most other Spanish–speaking countries, México was the preferred spelling. In recent years, the Real Academia Española, which regulates the Spanish l
Sierra Madre Oriental
The Sierra Madre Oriental is a mountain range in northeastern Mexico. The Sierra Madre Oriental is part of the American Cordillera, a chain of mountain ranges that consists of an continuous sequence of mountain ranges that form the western "backbone" of North America, Central America, South America and Antarctica. Spanning 1,000 kilometres the Sierra Madre Oriental runs from the Rio Grande on the border between Coahuila and Texas south through Nuevo León, southwest Tamaulipas, San Luis Potosí, Querétaro, Hidalgo to northern Puebla, where it joins with the east-west running Eje Volcánico Transversal of central Mexico; the northernmost are the Sierra del Burro and the Sierra del Carmen which reach the border with the United States at the Rio Grande. North of the Rio Grande, the range continues northwestward into Texas and beyond as the Davis and Guadalupe Ranges. Mexico's Gulf Coastal Plain lies to the east of the range, between the mountains and the Gulf of Mexico coast; the Mexican Plateau, which averages 1,100 metres in elevation, lies between the Sierra Madre Oriental and the Sierra Madre Occidental further west.
The climate of the Sierra Madre Oriental is drier than the rainforest areas further south. The highest point is Cerro San Rafael, at 3,700 metres above sea level, is the highest point of the Sierra Madre Oriental and the state of Coahuila and the second in Mexico in isolation; this long range of tall mountains is noted for its abundant biodiversity and large number of endemic species of plants and wildlife, from the dry north to the wetter south. The Sierra Madre Oriental pine-oak forests are found at high elevations in the range. To the east, the Tamaulipan matorral occupies the range's lower slopes in Nuevo León and northern Tamaulipas, while the Veracruz moist forests cover the lower slopes of the central range, the eastern slopes at the southern end of the range are home to the Veracruz montane forests. West of the range, the Mexican Plateau is home to deserts and xeric shrublands, including the Chihuahuan Desert to the north, the Meseta Central matorral on the central part of the plateau, the Central Mexican matorral on the southern plateau.
Much of the wildlife can be found in the Sierra Madre Occidental, which runs parallel to these mountains along western Mexico. Pine-oak forests are dominated by several species of pine, such as Pinus nelsonii, P. cembroides, P. pseudostrobus, P. arizonica, oak, such as Quercus castanea and Q. affinis. Matorral is characterized by woody shrubs, small trees and succulents. Montane chaparral is found above 1,700 m and is home to species in the genera Quercus, Yucca and Bauhinia. Piedmont scrub occurs below 2,000 m and is composed of plants 3 to 5 m in height such as Helietta parvifolia, Neopringlea integrifolia and Acacia spp; the canopy of moist forests is dominated by trees up to 30 m in height, including Brosimum alicastrum, Manilkara zapota, Celtis monoica, Bursera simaruba, Dendropanax arboreus, Sideroxylon capiri. Birds of the forest include the Mexican chickadee, Montezuma quail, Strickland's woodpecker, zone-tailed hawk and several species of jay. Pine-oak forests in Coahuila are part of the migration route of monarch butterflies.
Original habitats have been reduced by clearance for livestock grazing and logging over hundreds of years. Protected areas include the Cumbres de Monterrey National Park in Mexico and the Big Bend National Park in Texas; the El Cielo Biosphere in Tamaulipas preserves the northernmost tropical Veracruz moist forests in Mexico and extensive temperate cloud forests. Mountain peaks of Mexico "Sierra Madre Oriental pine-oak forests". Terrestrial Ecoregions. World Wildlife Fund
A normal route or normal way is the most used route for ascending and descending a mountain peak. It is the simplest route. In the Alps, routes are classed in the following ways, based on their waymarking and upkeep: Footpaths Hiking trails Mountain trails Alpine routes Climbing routes and High Alpine routes in combined rock and ice terrain, graded by difficultySometimes the normal route is not the easiest ascent to the summit, but just the one, most used. There may be technically easier variations; this is the case on the Watzmannfrau, the Hochkalter and Mount Everest. There may be many reasons these easier options are less well-used: the simplest route is less well known than the normal route; the technically easiest route is more arduous than another and is therefore used on the descent. The technically easiest route carries a much higher risk of e.g. rockfalls or avalanche and is therefore avoided in favour of a more difficult route. The technically easier route requires a complicated or long approach march, or all access may be banned via one country.
The term tourist route may sometimes be applied by those wishing to suggest that other routes up a mountain are somehow more "worthy". This belittling of the "normal route" therefore maintains a distinction between those perceiving themselves as serious mountaineers who disparage the incursion of tourist climbers into their domain
Mount Sanford (Alaska)
Mount Sanford is a shield volcano in the Wrangell Volcanic Field, in eastern Alaska near the Copper River. It is the sixth highest mountain in the United States and the third highest volcano behind Mount Bona and Mount Blackburn; the south face of the volcano, at the head of the Sanford Glacier, rises 8,000 feet in 1 mile resulting in one of the steepest gradients in North America. Mount Sanford is composed of andesite, is an ancient peak, being Pleistocene, although some of the upper parts of the mountain may be Holocene; the mountain first began developing 900,000 years ago, when it began growing on top of three smaller shield volcanoes that had coalesced. Although obscured by icefields, the uppermost 2,000 feet of the mountain appear to be a lava dome filling a larger summit crater. Two notable events in the mountain's history include a large rhyolite flow which traveled some 11 miles to the north east of the peak and has a volume of about 5 cubic miles, another flow which erupted from a rift zone on the flank of the volcano some 320,000 years ago.
The second flow marks the most recent activity of the volcano. The flow was dated using radiometric methods. Observers have reported minor activity at Sanford vapor clouds or plumes from ice and rockfalls; some reported incidents may have been orographic clouds, while others have been interpreted as avalanches. The majority of Mount Sanford above 8,000 feet is covered by icefields, merging to the south with that surrounding Mount Wrangell; the largest glacier on Sanford is the Sanford Glacier, whose source lies at the steep cirque that cuts into the south side of the mountain. The mountain was named in 1885 by Lieutenant Henry T. Allen of the U. S. Army, a descendant of Reuben Sanford. Mount Sanford was first climbed on July 21, 1938 by noted mountaineers Terris Moore and Bradford Washburn, via the still standard North Ramp route up the Sheep Glacier; this route "offers little technical difficulty" and "is a glacier hike all the way to the summit" but is still a serious mountaineering challenge due to the altitude and latitude of the peak.
The base of the route is accessed by air, but landing near the mountain is not straightforward. On March 12, 1948, Northwest Airlines Flight 4422 crashed into Mount Sanford. All 24 passengers and 6 crew members were killed; the wreckage was covered by snow and was not found again until 1999. The first solo ascent of Sanford was achieved on September 19, 1968, by Japanese mountaineer Naomi Uemura, who died just after making the first solo winter ascent of Denali. List of mountain peaks of North America List of mountain peaks of the United States List of mountain peaks of Alaska List of the highest major summits of the United States List of the most prominent summits of the United States List of the most isolated major summits of the United States List of volcanoes in the United States Richter, Donald H.. Guide to the Volcanoes of the Western Wrangell Mountains, Alaska. USGS Bulletin 2072. Richter, Donald H.. Geologic Map of the Wrangell-Saint Elias National Park and Preserve, Alaska. USGS Scientific Investigations Map 2877.
Winkler, Gary R.. A Geologic Guide to Wrangell—Saint Elias National Park and Preserve, Alaska: A Tectonic Collage of Northbound Terranes. USGS Professional Paper 1616. ISBN 0-607-92676-7. Wood, Charles A.. Volcanoes of North America. Cambridge University Press. ISBN 0-521-43811-X. Mount Sanford at the Alaska Volcano Observatory"Sanford Trip Report". Mt. Sanford Expedition via the Sheep Glacier, 2014. Retrieved 2014-08-14