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Ice, including snow, is the solid phase of water. It is useful to think of it this way rather than as "frozen water" because water can achieve the solid phase through the freezing of liquid water or by direct deposition (sublimation) of water vapour, its gaseous phase.
The Subarctic covers a relatively large area in eastern Canada; its western counterpart, formed where Pacific and Arctic waters meet and mix, is restricted to a narrow band along the shore of the Beaufort Sea (see Coastal Waters).
Sea ice formed by the freezing of seawater and floats on the surface of the polar oceans. Its coverage varies with the seasons; in the Northern Hemisphere sea ice ranges from a minimum of about 9 million km2 in September to a maximum of about 16 million km2 in March. In the Southern Hemisphere the range is from 3 million to 19 million km2, with the minimum and maximum coverage occurring in February and September respectively. The thickness of sea ice can vary from a few centimetres for newly formed ice in protected locations to 20 m or more in ridges; however, typical thicknesses are about 3 m in the Arctic and about 1 m in the Antarctic.
Canals and Inland Waterways
These 2 great journeys were first made just before the end of the 18th century, and by the same man. Alexander Mackenzie reached the mouth of the river which now bears his name in 1789, and was the first European to cross the North American continent (to Bella Coola) in 1793.
Hydroelectricity in Canada
Hydroelectricity is energy produced from flowing water. The amount of energy produced depends on volume and speed: the more water moving at a fast rate, the more energy produced. For this reason, many hydroelectric stations are built near waterfalls. To produce energy, water is directed toward turbines — sometimes with the help of a dam — causing them to spin. In turn, the turbines make electrical generators spin and electricity is produced. It is a renewable, comparatively nonpolluting energy source and Canada’s largest source of electric-power generation.
Worldwide, over two-thirds of precipitation falling on land surfaces is evaporated and transpired back into the atmosphere. In Canada less than 40% is evaporated and transpired; the remainder, called the water yield, enters into streamflow.
Ice caps are large masses of ice that rest on land and cover most of the underlying landscape.
The Manicouagan Reservoir, 1,942 km2, elevation 360 m, is located in southeastern Quebec, about 140 km from the Labrador border. The second-largest natural lake in Quebec, it was created by a meteorite millions of years ago. The name “Manicouagan” is possibly of Innu origin and might mean “where there is bark” (for canoe making). The lake appears on Jonathan Carver’s map of Quebec (1776) as Lake Asturagamicook, and is shown to be drained by the Manicouagan or Black River.
Floods in Canada
Floods are primarily caused by naturally occurring changes in the height of rivers, lakes and oceans. According to Public Safety Canada, floods are the most common natural hazard in the country and among the costliest. Historic floods have occurred across Canada, with many of the worst happening on major river systems that pass through populated areas. Scientists predict that flooding linked to the impacts of climate change will increase as the 21st century progresses, particularly in coastal areas of the country.
James Bay Project
In 1971, Hydro-Québec and the government of Quebec initiated the James Bay Project, a monumental hydroelectric-power development on the east coast of James Bay. (See also Hydroelectricity in Canada.) Over the course of two phases, a total of eight generating stations were built, allowing for the pollution-free production of a significant portion of Quebec’s electricity. However, the project also profoundly disrupted the environment and the Indigenous communities living in the region, the effects of which are still being felt today.