Mackenzie River
At , the Mackenzie River drainage basin encompasses nearly 20 percent of Canada. About , or 54 percent of the basin, lies above Great Slave Lake. Permafrost underlies about three-quarters of the watershed, reaching up to deep in the Mackenzie Delta. As a whole, the Mackenzie basin receives only meager to moderate rainfall, averaging over the entire basin, though mountain areas experience much higher precipitation, and areas near and north of the Arctic Circle receive much lower precipitation.
Canada
Since the end of the last glacial period, Canada has consisted of eight distinct forest regions, including extensive boreal forest on the Canadian Shield. Canada has over 2,000,000 lakes—563 greater than —which is more than any other country, containing much of the world's fresh water.
There are also fresh-water glaciers in the Canadian Rockies and the Coast Mountains.
Canada is geologically active, having many earthquakes and potentially active volcanoes, notably Mount Meager massif, Mount Garibaldi, Mount Cayley massif, and the Mount Edziza volcanic complex. The volcanic eruption of the Tseax Cone in 1775 was among Canada's worst natural disasters, killing an estimated 2,000 Nisga'a people and destroying their village in the Nass River valley of northern British Columbia. The eruption produced a lava flow, and, according to Nisga'a legend, blocked the flow of the Nass River.