Fraser River - Geography

Geography

The Fraser drains a 220,000 km² (85,000 sq mi) area. Its source is a dripping spring at Fraser Pass. The river then flows north to the Yellowhead Highway and west past Mount Robson to the Rocky Mountain Trench and the Robson Valley near Valemount. After running northwest past 54° north, it makes a sharp turn to the south at Giscome Portage, meeting the Nechako River at the city of Prince George, then continuing south, progressively cutting deeper and deeper into the Fraser Plateau to form the Fraser Canyon from roughly the confluence of the Chilcotin River, near the city of Williams Lake, southwards. It is joined by the Bridge and Seton Rivers at the town of Lillooet, then by the Thompson River at Lytton, where it proceeds south until it is approximately 40 miles (64 km) north of the 49th parallel, which is Canada's border with the United States.

From Lytton southwards it runs through a progressively deeper canyon between the Lillooet Ranges of the Coast Mountains on its west and the Cascade Mountains on its east. Hell's Gate, located immediately downstream of the town of Boston Bar, is a famous portion of the canyon where the walls narrow dramatically, forcing the entire volume of the river through a gap only 35 metres (115 feet) wide. An aerial tramway takes visitors out over the river; the feature is not visible from the main highway. Simon Fraser was forced to portage the gorge on his trip through the canyon in June of 1808. At Yale, at the head of navigation on the river, the canyon opens up and the river is wider, though without much adjoining lowland until Hope, where the river then turns west and southwest into a lush lowland valley, known as the Fraser Valley, past Chilliwack and the confluence of the Harrison and Sumas Rivers, bending northwest at Abbotsford and Mission, turning southwest again just east of New Westminster, where it splits into a North Arm, which is the southern boundary of the city of Vancouver, and the South Arm, which divides the City of Richmond from the Corporation of Delta.

Richmond is on the largest island in the Fraser, Lulu Island and also on Sea Island, which is the location of Vancouver Airport; the eastern end of Lulu Island is within the City of New Westminster and is called Queensborough. Also in the lowermost Fraser, among other smaller islands, is Annacis Island, an important industrial and port area, which lies to the southeast of the eastern end of Lulu Island (Sea, Lulu and Annacis Islands lie between the North and South Arms. Other notable islands in the lower Fraser are Barnston Island, Matsqui Island, Nicomen Island and Sea Bird Island.` Other islands lie on the outer side of the estuary, most notably Westham Island, a wildfowl preserve, and Iona Island, the location of the main sewage plant for the City of Vancouver.

After 100 kilometres (about 60 mi), it forms a delta where it empties into the Strait of Georgia between the mainland and Vancouver Island. The lands south of the City of Vancouver, including the cities of Richmond and Delta, sit on the flat flood plain. The islands of the delta include Iona Island, Sea Island, Lulu Island, Annacis Island, and a number of smaller islands. While the vast majority of the river's drainage basin lies within British Columbia, a small portion in the drainage basin lies across the international border in Washington in the United States, namely the upper reaches of the tributary Chilliwack and Sumas Rivers. Most of lowland Whatcom County, Washington is part of the Fraser Lowland and was formed also by sediment deposited from the Fraser, though most of the county is not in the Fraser drainage basin.

Similar to the Columbia River Gorge east of Portland, Oregon, the Fraser exploits a topographic cleft between two mountain ranges separating a more continental climate (in this case, that of the British Columbia Interior) from a milder climate near the coast. When an Arctic high-pressure area moves into the British Columbia Interior and a relatively low-pressure area builds over the general Puget Sound and Strait of Georgia region, the cold Arctic air accelerates southwest through the Fraser Canyon. These outflow winds can gust up to 60 to 80 miles per hour (97 to 130 km/h) and have at times exceeded 100 miles per hour (160 km/h). Such winds frequently reach Bellingham and the San Juan Islands, gaining strength over the open water of the Strait of Juan de Fuca.

The estuary at the river's mouth is a site of hemispheric importance in the Western Hemisphere Shorebird Reserve Network.