To the north of this region is the broad Canadian Shield, an area of rock scoured clean by the last ice age, thinly soiled, rich in minerals, and dotted with lakes and rivers. Canada by far has more lakes than any other country and has a large amount of the world's freshwater.
In eastern Canada, most people live in large urban centres on the flat Saint Lawrence Lowlands. The Saint Lawrence River widens into the world's largest estuary before flowing into the Gulf of Saint Lawrence. The gulf is bounded by Newfoundland to the north and the Maritimes to the south. The Maritimes protrude eastward along the Appalachian Mountain range from northern New England and the Gaspé Peninsula of Quebec. New Brunswick and Nova Scotia are divided by the Bay of Fundy, which experiences the world's largest tidal variations. Ontario and Hudson Bay dominate central Canada. West of Ontario, the broad, flat Canadian Prairies spread toward the Rocky Mountains, which separate them from British Columbia.
In northwestern Canada, the Mackenzie River flows from the Great Slave Lake to the Arctic Ocean. A tributary of a tributary of the Mackenzie is the South Nahanni River, which is home to Virginia Falls, a waterfall about twice as high as Niagara Falls. Mount Robson, Canadian Rockies in British Columbia. Northern Canadian vegetation tapers from coniferous forests to tundra and finally to Arctic barrens in the far north. The northern Canadian mainland is ringed with a vast archipelago containing some of the world's largest islands.
Average winter and summer high temperatures across Canada vary depending on the location. Winters can be harsh in many regions of the country, particularly in the interior and Prairie provinces which experience a continental climate, where daily average temperatures are near −15 °C (5 °F) but can drop below −40 °C (−40 °F) with severe wind chills. In non-coastal regions, snow can cover the ground almost six months of the year (more in the north). Coastal British Columbia is an exception and enjoys a temperate climate with a mild and rainy winter.
On the east and west coast, average high temperatures are generally in the low 20s °C (70s °F), while between the coasts the average summer high temperature ranges from 25 to 30 °C (75 to 85 °F) with occasional extreme heat in some interior locations exceeding 40 °C (104 °F). For a more complete description of climate across Canada see Environment Canada's Website. Canada is also geologically active, having many earthquakes and potentially active volcanoes, notably Mount Meager, Mount Garibaldi, Mount Cayley and the Mount Edziza volcanic complex. The volcanic eruption of Tseax Cone in 1775 caused a catastrophic disaster, killing 2,000 Nisga'a people and the destruction of their village in the Nass River valley of northern British Columbia; the eruption produced a 22.5 km (14 mi) lava flow and according to legend of the Nisga'a people, it blocked the flow of the Nass River.