of Vancouver Island is covered by a temperate rain forest. One-third of the province consists of barren alpine tundra, icefields, and glaciers. Mountains and mountain ranges The landforms of British Columbia include two major continental landforms, the Interior Plains in the province's northeast, the British Columbia portion of which is part of the Alberta Plateau. The rest of the province is part of the Western Cordillera of North America, often referred to in Canada as the Pacific Cordillera or Canadian Cordillera. The Cordillera is subdivided into four main "systems" (which are distinct from the corresponding region's geologic provinces): Eastern System B.C.'s Eastern Mountain System comprises the dominant Canadian Rockies, with the Cariboo, Selkirk, Monashee, and Purcell ranges of the Columbia Mountains system in the south, and the Hart Ranges & Muskwa Ranges of the Northern Rocky Mountains to the north The Canadian Rockies incorporate the Canadian segment of the North American Rocky Mountains range. The southern end in Alberta and British Columbia borders Idaho and Montana of the United States. The northern end is at the Liard Plain in British Columbia. Interior System The Interior System comprises the Interior Plateau and Interior Mountains (aka the Northern Interior Mountains) and the southern part of the Yukon Plateau. The major subdivisions of the Interior Mountains are the Cassiar Mountains, Omineca Mountains, Stikine Plateau, Skeena Mountains and Hazelton Mountains. Each has a variety of subranges and some definitions include the Tahltan Highland and Tagish Highland which may also be assigned to the Boundary Ranges of the Coast Mountains (see next). The major subdivisions of the Interior Plateau are the Nechako Plateau, the McGregor Plateau, the Fraser Plateau (which includes the Chilcotin Plateau and Cariboo Plateau and a number of small mountain ranges) and the Thompson Plateau. The Quesnel, Shuswap and Okanagan Highlands which flank the plateau to the east are sometimes seen as part of it, but are officially part of the Columbia Mountains range-system and are seen as subranges of the adjoining ranges, namely the Cariboo Mountains and Monashee Mountains. Western System The Western System comprises the Coast Mountains, the Canadian portion of the Cascade Mountains (known in the US as the Cascade Range), the southeasternmost Saint Elias Mountains and the Coastal Trough, which includes the Georgia Depression and its subunit the Fraser Lowland and other low-lying coastal areas. The Western Mountain System's Coast Mountains are the westernmost range of the Pacific