Hudson Bay is a large (1.23 million km²) body of water in northeastern Canada on the Arctic Ocean. It drains a large area that includes parts of Ontario, Quebec, Saskatchewan, Alberta, Manitoba and Nunavut, as well as parts of North Dakota and Minnesota. A smaller offshoot of the bay, James Bay, lies to its south.
The Eastern Cree name for Hudson and James Bay is Wînipekw (Southern dialect) or Wînipâkw (Northern dialect), meaning muddy or brackish water. Lake Winnipeg is similarly named by the local Cree, as is the location for the City of Winnipeg.
Hudson Bay was named after Henry Hudson, who explored the bay in 1610 on his ship the Discovery. On this fourth voyage he worked his way around the west coast of Greenland and into the bay, mapping much of its eastern coast. The Discovery became trapped in the ice over the winter, and the crew survived onshore at the southern tip of James Bay. When the ice cleared in the spring Hudson wanted to explore the rest of the area, but the crew mutinied on June 22, 1611, and left Hudson and others adrift in a small boat. No one to this day knows the fate of Hudson and his loyal crew.
Hudson's Bay Company
Sixty years later the Nonsuch reached the bay and successfully traded for beaver pelts with the Cree. This led to the creation of the Hudson's Bay Company (HBC), which bears its name to this day. The British crown awarded a trading monopoly on the Hudson Bay watershed, called Rupert's Land, to the Company. France contested this grant by sending several military expeditions to the region, but abandoned its claim in the Treaty of Utrecht (April, 1713).
During this period, the HBC built several forts and trading posts along the coast at the mouth of the major rivers such as Fort Severn, Ontario, York Factory, Manitoba and Churchill, Manitoba. These strategic locations allowed inland exploration and more importantly, facilitated the fur trade. The HBC continued to use these posts until the beginning of the 20th century. The port of Churchill is still today an important shipping link for trade with Europe and Russia.
This land, an area of approximately 3.9 million km², was ceded in 1870 to Canada as part of the Northwest Territories when the trade monopoly was abolished. Starting in 1913, the Bay was extensively charted by the Canadian Government's CSS Acadia to develop the bay for navigation.
Hudson Bay was the growth centre for the main ice sheet that covered northern North America during the last Ice Age. The legacy of this is the very low year round average temperatures in the whole region. (The average annual temperature for Churchill at 59°N is -5°C; by comparison Arkhangelsk at 64°N in a similar cold continental position in northern Russia has an average of 2°C.) Water temperature peaks at 8°-9°C on the western side of the bay in late summer. It is largely frozen over from mid-December to mid-June when it usually clears from its eastern end westwards and southwards. A steady increase in regional temperatures over the last 100 years has been reflected in a lengthening of the ice-free period which was as short as four months in the late 17th century.
Hudson Bay has a salinity that is lower than the world ocean on average. This is caused mainly by the low rate of evaporation, with the bay ice-covered for much of the year; the large volume of freshwater drainage entering the bay, about 700 km³ annually; and the limited connection with the larger Atlantic Ocean and its higher salinity.
The western shores of the bay are a lowland known as the Hudson Bay Lowlands. The area is drained by a large number of rivers and has formed a characteristic vegetation known as muskeg. Much of the landform has been shaped by the actions of glaciers and the shrinkage of the bay over long periods of time. Signs of numerous former beachfronts can be seen far inland from the current shore. A large portion of the lowlands in the province of Ontario is part of the Polar Bear Provincial Park, and a similar portion of the lowlands in Manitoba is contained in Wapusk National Park.
When Earth's gravitational field was mapped starting in the 1960s a large region of below-average gravity was detected in the Hudson Bay region. This was initially thought to be a result of the crust still being depressed from the weight of the Laurentide ice sheet during the most recent Ice Age, but more detailed observations taken by the GRACE satellite suggest that this effect cannot account for the entirety of the gravitational anomaly. It is thought that convection in the underlying mantle may be contributing.
Some of the larger communities on the shores of Hudson Bay are:
- GHCN climatic monthly data, GISS, using 1995-2007 annual averages
- General Survey of World Climatology, Landsberg ed., (1984), Elsevier.
- Young, Kelly. Satellites solve mystery of low gravity over Canada, New Scientist, 10 May 2007. Retrieved on 2007-05-11.