Canadian Pacific Railway
The Canadian Pacific Railway known as CP Rail between 1968 and 1996, known as Canadian Pacific is a historic Canadian Class I railroad incorporated in 1881. The railroad is owned by Canadian Pacific Railway Limited, which began operations as legal owner in a corporate restructuring in 2001. Headquartered in Calgary, Alberta, it owns 20,000 kilometres of track all across Canada and into the United States, stretching from Montreal to Vancouver, as far north as Edmonton, its rail network serves Minneapolis-St. Paul, Detroit and New York City in the United States; the railway was first built between eastern Canada and British Columbia between 1881 and 1885, fulfilling a promise extended to British Columbia when it entered Confederation in 1871. It was Canada's first transcontinental railway, but no longer reaches the Atlantic coast. A freight railway, the CPR was for decades the only practical means of long-distance passenger transport in most regions of Canada, was instrumental in the settlement and development of Western Canada.
The CPR became one of the largest and most powerful companies in Canada, a position it held as late as 1975. Its primary passenger services were eliminated in 1986, after being assumed by Via Rail Canada in 1978. A beaver was chosen as the railway's logo in honor of Sir Donald A Smith who had risen from Factor to Governor of the Hudson's Bay Company over a lengthy career in the beaver fur trade. Smith was a principal financier of the C. P. R. Staking much of his personal wealth. In 1885, he drove the last spike to complete the transcontinental line; the company acquired two American lines in 2009: the Dakota and Eastern Railroad and the Iowa and Eastern Railroad. The trackage of the IC&E was at one time part of CP subsidiary Soo Line and predecessor line The Milwaukee Road; the combined DME/ICE system spanned North Dakota, South Dakota, Wisconsin and Iowa, as well as two short stretches into two other states, which included a line to Kansas City, a line to Chicago and regulatory approval to build a line into the Powder River Basin of Wyoming.
It is publicly traded on both the Toronto Stock Exchange and the New York Stock Exchange under the ticker CP. Its U. S. headquarters are in Minneapolis. Together with the Canadian Confederation, the creation of the Canadian Pacific Railway was a task undertaken as the National Dream by the Conservative government of Prime Minister Sir John A. Macdonald, he was helped by Sir Alexander Tilloch Galt, the owner of the North Western Coal and Navigation Company. British Columbia, a four-month sea voyage away from the East Coast, had insisted upon a land transport link to the East as a condition for joining Confederation; the government however proposed to build a railway linking the Pacific province to the Eastern provinces within 10 years of 20 July 1871. Macdonald saw it as essential to the creation of a unified Canadian nation that would stretch across the continent. Moreover, manufacturing interests in Quebec and Ontario wanted access to raw materials and markets in Western Canada; the first obstacle to its construction was political.
The logical route went through the city of Chicago, Illinois. In addition to this was the difficulty of building a railroad through the Canadian Rockies. To ensure this routing, the government offered huge incentives including vast grants of land in the West. In 1873, Sir John A. Macdonald and other high-ranking politicians, bribed in the Pacific Scandal, granted federal contracts to Hugh Allan's Canada Pacific Railway Company rather than to David Lewis Macpherson's Inter-Ocean Railway Company, thought to have connections to the American Northern Pacific Railway Company; because of this scandal, the Conservative Party was removed from office in 1873. The new Liberal prime minister, Alexander Mackenzie, ordered construction of segments of the railway as a public enterprise under the supervision of the Department of Public Works led by Sandford Fleming. Surveying was carried out during the first years of a number of alternative routes in this virgin territory followed by construction of a telegraph along the lines, agreed upon.
The Thunder Bay section linking Lake Superior to Winnipeg was commenced in 1875. By 1880, around 1,000 kilometres was nearly complete across the troublesome Canadian Shield terrain, with trains running on only 500 kilometres of track. With Macdonald's return to power on 16 October 1878, a more aggressive construction policy was adopted. Macdonald confirmed that Port Moody would be the terminus of the transcontinental railway, announced that the railway would follow the Fraser and Thompson rivers between Port Moody and Kamloops. In 1879, the federal government floated bonds in London and called for tenders to construct the 206 km section of the railway from Yale, British Columbia, to Savona's Ferry, on Kamloops Lake; the contract was awarded to Andrew Onderdonk, whose men started work on 15 May 1880. After the completion of that section, Onderdonk received contracts to build between Yale and Port Moody, between Savona's Ferry and Eagle Pass. On 21 October 1880, a new syndicate, unrelated to Hugh Allan's, signed
Alberta is a western province of Canada. With an estimated population of 4,067,175 as of 2016 census, it is Canada's fourth most populous province and the most populous of Canada's three prairie provinces, its area is about 660,000 square kilometres. Alberta and its neighbour Saskatchewan were districts of the Northwest Territories until they were established as provinces on September 1, 1905; the premier has been Rachel Notley since May 2015. Alberta is bounded by the provinces of British Columbia to the west and Saskatchewan to the east, the Northwest Territories to the north, the U. S. state of Montana to the south. Alberta is one of three Canadian provinces and territories to border only a single U. S. state and one of only two landlocked provinces. It has a predominantly humid continental climate, with stark contrasts over a year. Alberta's capital, Edmonton, is near the geographic centre of the province and is the primary supply and service hub for Canada's crude oil, the Athabasca oil sands and other northern resource industries.
About 290 km south of the capital is the largest city in Alberta. Calgary and Edmonton centre Alberta's two census metropolitan areas, both of which have populations exceeding one million, while the province has 16 census agglomerations. Tourist destinations in the province include Banff, Drumheller, Sylvan Lake and Lake Louise. Alberta is named after the fourth daughter of Queen Victoria. Princess Louise was the wife of Marquess of Lorne, Governor General of Canada. Lake Louise and Mount Alberta were named in her honour. Alberta, with an area of 661,848 km2, is the fourth-largest province after Quebec and British Columbia. To the south, the province borders on the 49th parallel north, separating it from the U. S. state of Montana, while to the north the 60th parallel north divides it from the Northwest Territories. To the east, the 110th meridian west separates it from the province of Saskatchewan, while on the west its boundary with British Columbia follows the 120th meridian west south from the Northwest Territories at 60°N until it reaches the Continental Divide at the Rocky Mountains, from that point follows the line of peaks marking the Continental Divide in a southeasterly direction until it reaches the Montana border at 49°N.
The province extends 660 km east to west at its maximum width. Its highest point is 3,747 m at the summit of Mount Columbia in the Rocky Mountains along the southwest border while its lowest point is 152 m on the Slave River in Wood Buffalo National Park in the northeast. With the exception of the semi-arid steppe of the south-eastern section, the province has adequate water resources. There are numerous lakes used for swimming, fishing and a range of water sports. There are three large lakes, Lake Claire in Wood Buffalo National Park, Lesser Slave Lake, Lake Athabasca which lies in both Alberta and Saskatchewan; the longest river in the province is the Athabasca River which travels 1,538 km from the Columbia Icefield in the Rocky Mountains to Lake Athabasca. The largest river is the Peace River with an average flow of 2161 m3/s; the Peace River originates in the Rocky Mountains of northern British Columbia and flows through northern Alberta and into the Slave River, a tributary of the Mackenzie River.
Alberta's capital city, Edmonton, is located at about the geographic centre of the province. It is the most northerly major city in Canada, serves as a gateway and hub for resource development in northern Canada; the region, with its proximity to Canada's largest oil fields, has most of western Canada's oil refinery capacity. Calgary is about 280 km south of Edmonton and 240 km north of Montana, surrounded by extensive ranching country. 75% of the province's population lives in the Calgary–Edmonton Corridor. The land grant policy to the railroads served as a means to populate the province in its early years. Most of the northern half of the province is boreal forest, while the Rocky Mountains along the southwestern boundary are forested; the southern quarter of the province is prairie, ranging from shortgrass prairie in the southeastern corner to mixed grass prairie in an arc to the west and north of it. The central aspen parkland region extending in a broad arc between the prairies and the forests, from Calgary, north to Edmonton, east to Lloydminster, contains the most fertile soil in the province and most of the population.
Much of the unforested part of Alberta is given over either to grain or to dairy farming, with mixed farming more common in the north and centre, while ranching and irrigated agriculture predominate in the south. The Alberta badlands are located in southeastern Alberta, where the Red Deer River crosses the flat prairie and farmland, features deep canyons and striking landforms. Dinosaur Provincial Park, near Brooks, showcases the badlands terrain, desert flora, remnants from Alberta's past when dinosaurs roamed the lush landscape. Alberta has a humid continental climate with cold winters; the province is open to cold arctic weather systems from the north, which produce cold conditions in winter. As the fronts between the air masses shift north and south across Alberta, the temperature can change rapidly. Arctic
Canadian Northern Railway
The Canadian Northern Railway is a historic Canadian transcontinental railway. At its demise in 1923, when it was merged into the Canadian National Railway, the CNoR owned a main line between Quebec City and Vancouver via Ottawa and Edmonton. CNoR had its start in the independent branchlines that were being constructed in Manitoba in the 1880s and 1890s as a response to the monopoly exercised by Canadian Pacific Railway. Many of these branchlines were built with the sponsorship of the provincial government, which sought to subsidize local competition to the federally subsidized CPR. Two of these branchline contractors, Sir William Mackenzie and Sir Donald Mann, took control of the bankrupt Lake Manitoba Railway and Canal Company in January, 1896. Mackenzie and Mann expanded their enterprise, in 1897, by building further north into Manitoba's Interlake district as well as east and west of Winnipeg, they began building and buying lines south to connect the U. S. border at Pembina, North Dakota, east to Ontario.
The Canadian Northern Railway was established, in 1899, all railway companies owned by Mackenzie and Mann were consolidated into the new entity. CNoR's first step toward competing directly with CPR came at the start of the 20th century with the decision to build a line linking the Prairie Provinces with Lake Superior at the harbour in Port Arthur-Fort William which would permit the shipping of western grain to European markets as well as the transport of eastern Canadian goods to the West; this line incorporated an existing CNoR line to Lake of the Woods and two local Ontario railways, the Port Arthur and Western Railway and the Ontario and Rainy River Railway whose charters Mackenzie and Mann had acquired in 1897. To reach Port Arthur which became the lake terminus of the CNoR, the line extended south of Lake of the Woods into northern Minnesota before heading northeast through Rainy River District to the head of navigation on the Great Lakes; the Winnipeg-Port Arthur line was completed on December 30, 1901 with the last spike being driven just east of Atikokan station by Ontario's Commissioner of Crown Lands, Elihu Davis.
Throughout this time and Mann had been busy expanding their prairie branch line network to feed the connection to Port Arthur. This network expanded in subsequent years to cover most parts of the prairies. In 1903, the federal government and Grand Trunk Railway were seeking a 2nd transcontinental railway for Canada and approached Mackenzie and Mann to seek their co-operation; this effort was spurned and GTR and the federal government would go on to form a system composed of the Grand Trunk Pacific Railway and the National Transcontinental Railway. Mackenzie and Mann began their first significant expansion outside of the prairies with the purchase of Great Lakes steamships, the fr:Quebec and Lake St-John Railway into northern Quebec's Saguenay region and the acquisition of branchlines in southwestern Nova Scotia and western Cape Breton Island. Other acquisitions were in southern Ontario and a connecting line was built from Toronto to Parry Sound. In 1905, CNoR reached Edmonton, which had just been named capital of the newly formed province of Alberta.
In Eastern Canada, in 1908, a line was built east from a connection at Capreol, Ontario, on the Toronto – Parry Sound line to Ottawa and on to Montreal. In 1910 a direct Toronto–Montreal line was built. In 1911, federal funding was made available for construction of the line Montreal – Ottawa – Capreol – Port Arthur. In 1912, with GTR and CPR holding the ideal southern routes around Mount Royal to downtown Montreal, CNoR started building a double-tracked mainline north by building the Mount Royal Tunnel under the mountain. In western Canada, in 1910 construction was started on the line west of Edmonton through Yellowhead Pass to Vancouver, thanks to subsidies provided by the government of British Columbia. In 1911, work was started on a new townsite named Port Mann on the Fraser River that would accommodate the new car shops and from where lines would extend to Vancouver and to the delta of the Fraser River CNoR's initial expansion in the 1890s and 1900s had been frugal by acquiring bankrupt companies or finishing failed construction projects.
By the 1910s, significant expenses were adding up from the construction north of Lake Superior and the Mount Royal Tunnel, but the largest costs were from building on "the wrong side" of the Thompson and Fraser rivers in the mountains of British Columbia. CPR had trackage on the desirable eastern side, leading to the port of Vancouver, forcing CNoR to blast tunnels and ledges out of these canyons; the most infamous construction folly on the CNoR in British Columbia happened in 1913, when blasting for a passage for the railway at Hells Gate triggered an enormous landslide which blocked the narrow swift-flowing Fraser River. The resulting damage to Pacific salmon runs took decades to reverse by the governmental construction of fishways. In addition to difficult construction between Jasper and Vancouver, CNoR started construction west of Edmonton in 1910 two years than GTPR, which had started construction east from Prince Rupert in the Skeena River, leading to Yellowhead Pass. In 1910 the company entered the trans-Atlantic liner business with the founding of the Canadian Northern Steamship Company.
The subsidiary acquired two liners from the Egyptian Mail Steamship Company and operated them under its Royal Line brand. The pair of ships were renamed upon purchase—Cairo became Royal Edward and Heliopolis became Royal
Calgary is a city in the Canadian province of Alberta. It is situated at the confluence of the Bow River and the Elbow River in the south of the province, in an area of foothills and prairie, about 80 km east of the front ranges of the Canadian Rockies; the city anchors the south end of what Statistics Canada defines as the "Calgary–Edmonton Corridor". The city had a population of 1,267,344 in 2018, making it Alberta's largest city and Canada's third-largest municipality. In 2016, Calgary had a metropolitan population of 1,392,609, making it the fourth-largest census metropolitan area in Canada; the economy of Calgary includes activity in the energy, financial services and television, transportation and logistics, manufacturing, aerospace and wellness, tourism sectors. The Calgary CMA is home to the second-highest number of corporate head offices in Canada among the country's 800 largest corporations. In 2015, Calgary had the highest number of millionaires per capita of any major city in Canada.
In 1988, Calgary became the first Canadian city to host the Winter Olympic Games. Calgary has been recognized for its high quality of life. In 2018, The Economist magazine ranked Calgary the fourth-most liveable city in the world in their Global Liveability Ranking. Calgary is classed as a Beta global city. Calgary was named after Calgary on the Isle of Scotland. In turn, the name originates from a compound of kald and gart, similar Old Norse words, meaning "cold" and "garden" used when named by the Vikings who inhabited the Inner Hebrides. Alternatively, the name might be Gaelic Cala ghearraidh, meaning "beach of the meadow", or Gaelic for either "clear running water" or "bay farm"; the indigenous peoples of Southern Alberta referred to the Calgary area as "elbow", in reference to the sharp bend made by the Bow River and the Elbow River. In some cases, the area was named after the reeds that grew along the riverbanks, which were used to fashion bows. In the Blackfoot language, the area was known as Mohkínstsis akápiyoyis, meaning "elbow many houses", reflecting its strong settler presence.
The shorter form of the Blackfoot name, Mohkínstsis meaning "elbow", has been the popular Indigenous term for the Calgary area. In the Nakoda language, the area is known as Wincheesh-pah or Wenchi Ispase, both meaning "elbow". In the Nehiyaw Language, the area was known as Otoskwanik meaning "house at the elbow" or Otoskwunee meaning "elbow". In the Tsuut'ina language, the area is known as Kootsisáw meaning "elbow". In the Slavey language, the area was known as Klincho-tinay-indihay meaning "many horse town", referring to the Calgary Stampede and the city's settler heritage. There have been several attempts to revive the indigenous names of Calgary. In response to the Truth and Reconciliation Commission, local post-secondary institutions have adopted "official acknowledgements" of indigenous territory using the Blackfoot name of the City, Mohkínstsis. In 2017, the Stoney Nakoda sent an application to the Government of Alberta, to rename Calgary as Wichispa Oyade meaning "elbow town", however this has been challenged by the Piikani Blackfoot.
The Calgary area was inhabited by pre-Clovis people whose presence has been traced back at least 11,000 years. The area has been inhabited by the Niitsitapi, îyârhe Nakoda, the Tsuut'ina First Nations peoples and Métis Nation, Region 3; as Mayor Naheed Nenshi describes, "There have always been people here. In Biblical times there were people here. For generations beyond number, people have come here to this land, drawn here by the water, they come here to fish. He was the first recorded European to visit the area. John Glenn was the first documented European settler in the Calgary area, in 1873. In 1875, the site became a post of the North-West Mounted Police; the NWMP detachment was assigned to protect the western plains from US whisky traders, to protect the fur trade. Named Fort Brisebois, after NWMP officer Éphrem-A. Brisebois, it was renamed Fort Calgary in 1876 by Colonel James Macleod; when the Canadian Pacific Railway reached the area in 1883, a rail station was constructed, Calgary began to grow into an important commercial and agricultural centre.
Over a century the Canadian Pacific Railway headquarters moved to Calgary from Montreal in 1996. Calgary was incorporated as a town in 1884, elected its first mayor, George Murdoch. In 1894, it was incorporated as "The City of Calgary" in what was the North-West Territories; the Calgary Police Service was established in 1885 and assumed municipal, local duties from the NWMP. The Calgary Fire of 1886 occurred on November 7, 1886. Fourteen buildings were destroyed with losses estimated at $103,200. Although no one was killed or injured, city officials drafted a law requiring all large downtown buildings to be built with Paskapoo sandstone, to prevent this from happening again. After the arrival of the railway, the Dominion Government started leasing grazing land at minimal cost; as a result of this policy, large ranching operations were established in the outlying country near Calgary. A transportation and distribution hub, Calgary became the centre of Canada's cattle marketing and meatpacking industries.
By the late 19th century, the Hud
Provinces and territories of Canada
The provinces and territories of Canada are the sub-national governments within the geographical areas of Canada under the authority of the Canadian Constitution. In the 1867 Canadian Confederation, three provinces of British North America—New Brunswick, Nova Scotia, the Province of Canada —were united to form a federated colony, becoming a sovereign nation in the next century. Over its history, Canada's international borders have changed several times, the country has grown from the original four provinces to the current ten provinces and three territories. Together, the provinces and territories make up the world's second-largest country by area. Several of the provinces were former British colonies, Quebec was a French colony, while others were added as Canada grew; the three territories govern the rest of the area of the former British North America. The major difference between a Canadian province and a territory is that provinces receive their power and authority from the Constitution Act, 1867, whereas territorial governments have powers delegated to them by the Parliament of Canada.
The powers flowing from the Constitution Act are divided between the Government of Canada and the provincial governments to exercise exclusively. A change to the division of powers between the federal government and the provinces requires a constitutional amendment, whereas a similar change affecting the territories can be performed unilaterally by the Parliament of Canada or government. In modern Canadian constitutional theory, the provinces are considered to be sovereign within certain areas based on the divisions of responsibility between the provincial and federal government within the Constitution Act 1867, each province thus has its own representative of the Canadian "Crown", the lieutenant governor; the territories are not sovereign, but instead their authorities and responsibilities come directly from the federal level, as a result, have a commissioner instead of a lieutenant governor. Notes: There are three territories in Canada. Unlike the provinces, the territories of Canada have no inherent sovereignty and have only those powers delegated to them by the federal government.
They include all of mainland Canada north of latitude 60° north and west of Hudson Bay, as well as most islands north of the Canadian mainland. The following table lists the territories in order of precedence. Ontario, New Brunswick, Nova Scotia were the original provinces, formed when several British North American colonies federated on July 1, 1867, into the Dominion of Canada and by stages began accruing the indicia of sovereignty from the United Kingdom. Prior to this and Quebec were united as the Province of Canada. Over the following years, British Columbia, Prince Edward Island were added as provinces; the British Crown had claimed two large areas north-west of the Canadian colony, known as Rupert's Land and the North-Western Territory and assigned them to the Hudson's Bay Company. In 1870, the company relinquished its claims for £300,000, assigning the vast territory to the Government of Canada. Subsequently, the area was re-organized into the province of the Northwest Territories; the Northwest Territories were vast at first, encompassing all of current northern and western Canada, except for the British holdings in the Arctic islands and the Colony of British Columbia.
The British claims to the Arctic islands were transferred to Canada in 1880, adding to the size of the Northwest Territories. The year of 1898 saw the Yukon Territory renamed as Yukon, carved from the parts of the Northwest Territories surrounding the Klondike gold fields. On September 1, 1905, a portion of the Northwest Territories south of the 60th parallel north became the provinces of Alberta and Saskatchewan. In 1912, the boundaries of Quebec and Manitoba were expanded northward: Manitoba's to the 60° parallel, Ontario's to Hudson Bay and Quebec's to encompass the District of Ungava. In 1869, the people of Newfoundland voted to remain a British colony over fears that taxes would increase with Confederation, that the economic policy of the Canadian government would favour mainland industries. In 1907, Newfoundland acquired dominion status. In the middle of the Great Depression in Canada with Newfoundland facing a prolonged period of economic crisis, the legislature turned over political control to the Newfoundland Commission of Government in 1933.
Following Canada's participation in World War II, in a 1948 referendum, a narrow majority of Newfoundland citizens voted to join the Confederation, on March 31, 1949, Newfoundland became Canada's tenth province. In 2001, it was renamed Newfoundland and Labrador. In 1903, the Alaska Panhandle Dispute fixed British Columbia's northwestern boundary; this was one of only two provinces in Canadian history to have its size reduced. The second reduction, in 1927, occurred when a boundary dispute between Canada and the Dominion of Newfoundland saw Labrador increased at Quebec's expense – this land returned to Canada, as part of the province of Newfoundland, in 1949. In 1999, Nunavut was created from the eastern portion of the Northwest Territories. Yukon lies in the western portion of Northern Canada. All t
Red Deer County
Red Deer County is a municipal district in central Alberta, Canada within Census Division No. 8 and surrounding the City of Red Deer. The neighbouring municipalities of Red Deer County are Clearwater County to the west, Lacombe County to the north, the County of Stettler No. 6 to the east, Kneehill County to the southeast and Mountain View County to the south. It is located midway between Edmonton and Calgary, bisected by the Queen Elizabeth II Highway and bounded on the north and east by the Red Deer River. Red Deer County is an agricultural area, much of the rural land is used for growing crops, feeding livestock and providing lumber and mineral resources; the County has initiated several projects to ensure that agriculture and the environment are represented as it continues to grow. An Agricultural Profile has been created to detail the County's existing agriculture and water resources; the County was divided into 19 distinct geographic areas called County Neighbourhoods. These delineations distinguish variations in drainage, soil type, water resources, primary production.
County Neighbourhoods have specific characteristics that will assist future growth and development plans. Livestock and crop production are an important part of the economy; the County has dairies that make cheese, U-pick vegetable and fruit farms and the largest organic farm in Alberta. Amenities for trout fishing exist at a U-fish pod; the County has elk and apiary farms as well as a mouse farm, which raises white mice for the pet food industry. Construction of residences and most buildings in Red Deer County require County-issued development permits to assure that proposed projects are in conformance with applicable County bylaws and statutory plans and are consistent with requirements regulating property divisions and uses such as setbacks, minimum frontage, potable water supply and sewage disposal systems; as well, permits are required from other agencies such as Alberta Transportation or Alberta Environment. Although the County has no jurisdiction in these areas, it can assist applicants through the process.
In the 2016 Census of Population conducted by Statistics Canada, Red Deer County recorded a population of 19,541 living in 7,097 of its 8,440 total private dwellings, a 6.7% change from its 2011 population of 18,316. With a land area of 3,961.85 km2, it had a population density of 4.9/km2 in 2016. In the 2011 Census, Red Deer County had a population of 18,351 living in 6,643 of its 7,703 total dwellings, a -1.6% change from its 2006 adjusted population of 18,649. With a land area of 3,949 km2, it had a population density of 4.6/km2 in 2011. List of communities in Alberta List of municipal districts in Alberta Official website
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