Sumas Prairie is a landform in

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

and the State of Washington,

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. Part of the

Fraser Lowland The Fraser Lowland is a landform and physiographic region in the Pacific Northwest of North America, shared between the Canadian province of British Columbia and the U.S. state of Washington. The region includes much of the Lower Mainland region ...

, it was created by the draining of

Sumas Lake Sumas () is a city in Whatcom County, Washington, United States. It had a population of 1,307 as of the 2010 census. Sumas is located adjacent to the Canada–U.S. border and borders the city of Abbotsford, British Columbia. The Sumas-Huntingd ...

early in the 20th Century, and extends from the Vedder Canal southwestwards into northern

Whatcom County, Washington Whatcom County is a county located in the northwestern corner of the U.S. state of Washington, bordered by the Canadian Lower Mainland (the Metro Vancouver and Fraser Valley Regional Districts of British Columbia) to the north, Okanogan Coun ...

. The

British Columbia Highway 1 Highway 1 is a Provincial highways in British Columbia, provincial highway in British Columbia, Canada, that carries the main route of the Trans-Canada Highway (TCH). The highway is long and connects Vancouver Island, the Greater Vancouver regi ...

traverses the former lakebed on the prairie between Abbotsford and Chilliwack. All of its Canadian portion, except its northeasternmost area around

Yarrow ''Achillea millefolium'', commonly known as yarrow () or common yarrow, is a flowering plant in the family Asteraceae. Other common names include old man's pepper, devil's nettle, sanguinary, milfoil, soldier's woundwort, and thousand seal. The ...

, which is part of today's City of Chilliwack, was formerly the District of Sumas, which was amalgamated into the

City of Abbotsford Abbotsford is a city located in British Columbia, adjacent to the Canada–United States border, Greater Vancouver and the Fraser River. With an estimated population of 153,524 people it is the largest municipality in the province outside metrop ...

in 1972. 800px, center, View of Sumas Prairie from Lower Sumas Mountain, Abbotsford.

Flooding

Since the draining of the lake, Sumas Prairie has periodically flooded during major spring freshets of the

Fraser River The Fraser River is the longest river within British Columbia, Canada, rising at Fraser Pass near Blackrock Mountain in the Rocky Mountains and flowing for , into the Strait of Georgia just south of the City of Vancouver. The river's annual d ...

, occurring in 1894, 1948, 1972, and 2007. The prairie has also flooded due to extreme rainfall events, occurring in November 1990 and November 2021. During the 2021 British Columbia and Washington floods, the Sumas Prairie flooded, forcing evacuation of 1100 homes. Floodwaters came from the

Nooksack River The Nooksack River is a river in western Whatcom County of the northwestern U.S. state of Washington, draining extensive valley systems within the North Cascades around Mount Shuksan, Mount Baker and the Twin Sisters, and a portion of Fraser Lo ...

in neighboring

Washington State Washington (), officially the State of Washington, is a state in the Pacific Northwest region of the Western United States. Named for George Washington—the first U.S. president—the state was formed from the western part of the Washington ...

, which usually flows towards

Bellingham Bay Bellingham Bay is a bay of the Salish Sea located in Washington State in the United States. It is separated from the Strait of Georgia on the west by the Lummi Peninsula, Portage Island, and Lummi Island. It is bordered on the east by Bellingha ...

. On November 19, 2021, Abbotsford mayor Henry Braun announced that the

Canadian Army The Canadian Army (french: Armée canadienne) is the command responsible for the operational readiness of the conventional ground forces of the Canadian Armed Forces. It maintains regular forces units at bases across Canada, and is also respo ...

would build a levee to replace a broken dike and prevent the Sumas Prairie from further flooding. He said that this would lead to the flooding of about a dozen homes, but this was the only available option to prevent even more flooding.

References

Lower Mainland Landforms of British Columbia Landforms of Whatcom County, Washington {{BritishColumbiaCoast-geo-stub

Flooding

See also

References