Coast Mountains
Major mountain range in western North America.
The Coast Mountains are a major mountain range within the Pacific Coast Ranges of western North America, stretching from southwestern Yukon through the Alaska Panhandle and along nearly the entire coast of British Columbia down to the Fraser River. Their name reflects their proximity to the sea, and they are commonly called the Coast Range. This range comprises both volcanic and non-volcanic peaks, as well as extensive ice fields, including the largest temperate-latitude icecaps in the world. It is part of the larger Pacific Mountain System and the American Cordillera, a near-continuous sequence of mountain ranges forming the western backbone of the Americas. The range is divided into three subdivisions: the southern Pacific Ranges, the central Kitimat Ranges, and the northern Boundary Ranges. The Pacific Ranges contain Mount Waddington, the highest peak in the range and the highest mountain entirely within British Columbia. The western slopes are covered in dense temperate rainforest, while the eastern flanges taper to the dry Interior Plateau and subarctic boreal forests. Geologically, the Coast Mountains are built from deformed igneous and metamorphic rocks of diverse origins, assembled from several different terranes. They are part of the Pacific Ring of Fire, and their southern portion is shaped by the subduction of oceanic crust, forming a line of volcanoes known as the Garibaldi Volcanic Belt. Further north, a large continental rift has created additional volcanoes within the Northern Cordilleran Volcanic Province, the most volcanically active area in Canada. The mountains profoundly influence British Columbia’s climate by forcing moisture-laden Pacific air to rise, dropping some of the heaviest precipitation in North America on the western slopes, while the eastern slopes remain relatively dry.
- subdivisions
- Pacific Ranges, Kitimat Ranges, Boundary Ranges
- part_of
- Pacific Coast Ranges, American Cordillera, Pacific Ring of Fire
Lore & Background
The Coast Mountains extend from southwestern Yukon through the Alaska Panhandle and along nearly the entire coast of British Columbia, south to the Fraser River. Their name comes from their proximity to the sea. The range includes both volcanic and non-volcanic mountains, extensive ice fields, and the northern end of the Cascade Volcanoes. The mountains are part of the Pacific Ring of Fire. The range is divided into three sections: the southern Pacific Ranges, the central Kitimat Ranges, and the northern Boundary Ranges. The Pacific Ranges contain four of the five major coastal icecaps in the southern part of the range, which are among the largest temperate-latitude ice fields in the world. Mount Waddington, the highest peak entirely within British Columbia, is located here. The western slopes are covered in dense temperate rainforest, while the eastern flanks taper to the dry Interior Plateau. The mountains force moisture-laden Pacific air to rise, causing some of the heaviest precipitation in North America on the western slopes, while the eastern side remains relatively dry. The range is built from multiple terranes of different ages and tectonic origins, and its southern portion features a north–south line of young, explosive volcanoes.
Reader's Guide
The Coast Mountains are significant for their role in shaping the climate of British Columbia. By forcing moisture-laden air off the Pacific Ocean to rise, they drop heavy rainfall on their western slopes, supporting dense temperate rainforests, while the eastern slopes are relatively dry and protect the Interior Plateau from Pacific weather systems. Geologically, the range is built from several terranes of different ages and tectonic origins, including deformed igneous and metamorphosed pre-Tertiary rocks. The range's formation involved the collision of the Insular Islands with the continental margin and subsequent volcanic activity from the Coast Range Arc. The Coast Mountains remain largely undeveloped except for logging and the ski resort at Whistler.
Did You Know?
- The Coast Mountains extend from southwestern Yukon through the Alaska Panhandle and virtually all of the Coast of British Columbia south to the Fraser River.
- The Pacific Ranges include four of the five major coastal icecaps in the southern Coast Mountains, which are the largest temperate-latitude icecaps in the world.
- Mount Waddington, the highest mountain of the range, lies in the Waddington Range of the Pacific Ranges.
- The Coast Mountains are part of the Pacific Ring of Fire and contain volcanoes of the Garibaldi Volcanic Belt and the Northern Cordilleran Volcanic Province.
- The range's formation involved the collision of the Insular Islands with the continental margin and subsequent volcanic activity from the Coast Range Arc.
Frequently Asked Questions
Where exactly are the Coast Mountains located?
They run along the Pacific coast of western North America, from southwestern Yukon through the Alaska Panhandle and down the British Columbia coast to the Fraser River. The range is a core component of the Pacific Coast Ranges.
What is the highest peak in the Coast Mountains?
Mount Waddington tops the range at 4,019 m (13,186 ft) above sea level. It is situated within the Pacific Ranges subdivision.
How large are the Coast Mountains overall?
The range stretches roughly 1,600 km (about 1,000 mi) in length and averages around 300 km (190 mi) in width. That makes it one of the most extensive mountain systems on the North American west coast.
What are the main subdivisions of the Coast Mountains?
The range is broken into three sections: the Pacific Ranges, the Kitimat Ranges, and the Boundary Ranges. Collectively they contain both volcanic and non-volcanic peaks as well as extensive ice fields.
Which larger geological systems do the Coast Mountains belong to?
They are part of the Pacific Coast Ranges, the broader American Cordillera, and the Pacific Mountain System. Their position within the Pacific Ring of Fire also accounts for the volcanic features found in portions of the range.
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