The Coast Mountains are a mountain range of the Pacific Cordillera, running along the north western shore of the North American continent, extending south from the Alaska Panhandle and covering most of coastal British Columbia. They are part of a larger grouping, the Pacific Coast Ranges, which includes the Alaska Range, the Chugach Mountains, the Saint Elias Mountains, the Cascade Range, the Sierra Nevada and the Sierra Madre Occidental in Mexico.

The Coast Mountains are approximately 1600 km long and average 200 km in width. Its southern and southeastern boundaries are described by the Fraser River and the Interior Plateau. North of the Nechako Diversion, the Coast Mountains are flanked on the inland side by the Hazelton Mountains, the Skeena Mountains, the Stikine Plateau and the Tahltan and Tagish Highlands. Its far northwestern edge is delimited by the Kelsall River at the north end of the Alaska Panhandle, beyond which are the Saint Elias Mountains.

Covered in dense temperate rainforest on its western exposures, the range rises to heavily glaciated peaks, including the largest temperate-latitude icefields in the world. It then tapers to the dry interior plateau on its eastern flanks, or to the subarctic boreal forest of the Skeena Mountains and Stikine Plateau.

Mount Waddington, at , is the highest peak in the Coast Mountains and also the highest peak entirely within British Columbia.

Although the Coast Mountains are commonly considered to be the westernmost range of the Pacific Cordillera, the Insular Mountains are the true westernmost range,^[1] which includes Vancouver Island and the Queen Charlotte Islands.

The largest icefield in the Coast Mountains is the Ha-Iltzuk Icefield.

Tectonic origin

The Coast Mountains has its origins with a formerly active volcanic arc, called the Coast Range Arc, which began forming about 100 million years ago. Over millions of yearsthe volcanoes of the Coast Range Arc had their summits worn down and isostatic rebound has caused their solidified magma chambers to rise, forming the Coast Mountains.

During the early to middle Miocene, the Coast Mountains were favored thermally-driven uplift arising from the Miocene passage of the Anahim hotspot beneath the range, and response to convergence in late Miocene-Pliocene time.

Significant peaks

The Coast Mountains.

Subranges

There are several subdivisions of the Coast Mountains. These include:

• The Boundary Ranges, which lie along the BC-Alaska border from the mouth of the Nass River to the Chilkoot Pass and include the vast Juneau Icefield and the even vaster Stikine Icecap.
• The Kitimat Ranges, which lie between the Nass and Bella Coola
• The Pacific Ranges, which lie between Bella Coola and the Lower Mainland. The Pacific Ranges contain the largest temperate-latitude icecaps in the world, each 25-40 km in diameter. These include the Ha-Iltzuk (Silverthrone), Klinaklini, Monarch, Waddington, Homathko, Lillooet and Pemberton Icecaps.
• The Chilcotin Ranges, which run on the inland lea of the Pacific Ranges between the head of the Klinaklini River and the confluence of the Bridge River and Fraser River near Lillooet. The Chilcotin Ranges are sometimes considered part of the Pacific Ranges.
• The Lillooet Ranges, lying between the Harrison-Lillooet drainage and the Fraser River, south of the BCR line. The Lillooet Ranges are sometimes considered part of the Pacific Ranges.
• The Front Ranges, which include the North Shore Mountains of Greater Vancouver and the coastal-lying lower ranges of the Sunshine Coast and skirting the coastal archipelago.

There are innumerable smaller named ranges, and informal names for many groupings, within these subdivisions. Some neighbouring ranges can be found in Interior Plateau and the Hazelton Mountains section of the Skeena Mountains (which are not part of the Coast Mountains but just inland).

References

cs:Pob?e?ní hory de:Coast Mountains et:Rannikuahelik es:Montañas Costeras fr:Chaîne côtière it:Montagne Costiere lt:Pakrant?s kalnai ru:????????? ?????? (???????? ???????) sk:Coast Mountains fi:Rannikkovuoret