Where Do Landslides Occur?
Some areas of British Columbia are more susceptible to landslides than others because
of their unique geological conditions:
The sedimentary rocks of the Skeena Mountains are the most prone to large slumps and shallow slides in the province.
Debris flows and torrents often occur in the humid west coast of Vancouver Island and the Queen Charlotte Islands within the Insular Mountains.
Dormant volcanic centres in the Coast Mountains (e.g., Mt. Garibaldi) are susceptible to rock and debris avalanches and flows.
Thick clay and silt-rich glacial sediments in the Northeastern Plateau are prone to soil creep and are frequently undercut by rivers, which results in slumps.
The steeply dipping beds of sedimentary rocks in the Rocky Mountains are prone to rock slides, topples, falls and avalanches.
The Interior Plateau contains weathered volcanic rock and glaciolacustrine sediments that are particularly susceptible to creep, slumping and sliding.
Metamorphic rocks in the Columbia Mountains are prone to rock slides and slumps.
Population centres and transportation routes in British Columbia are exposed to a great variety
|This structure near Williams Lake received considerable damage in 1992 from undercutting of the slope (photo courtesy of the Ministry of Health). |
|The Spences Bridge Slide dammed the Thompson River in 1905 and is typical of other slides in the Interior Plateau (photo courtesy of the Ministry of Environment, Lands and Parks).|
Historical Landslides in British Columbia
||Rubble Creek/Garibaldi (The Barrier)
||30 million cubic metres of rock dislodged|
||Displacement wave 12 metres high created by the slide caused 1 death|
||15 million cubic metre slide blocked Thompson River for 2 days|
||Damaged homes, farms and a highway|
||Spences Bridge/Thompson River
||Resulting wave caused 18 deaths|
||Hell's Gate/Thompson River
||Millions of dollars in lost fish stocks and in repair of fish migration corridor|
||Jane Camp/Britannia Mine
||200 000 cubic metres of rock; 56 deaths|
||Britannia Creek/Howe Sound
||Glacial dam burst, over 5 million cubic metres of water and debris|
||Debris 17 metres thick; 7 deaths|
||British Columbia's largest rock slide; 4 deaths|
||76 000 cubic metres of debris; 4 deaths|
||Boston Bar/Fraser River
||Train derailed in slump; 3 deaths|
||Mine waste movement; 2 deaths|
||Attachie Slide/Fort St. John
||Over 24 million cubic metres of sediment|
|1973 & 1975
||2 events, 22 000 cubic metres|
||13 million cubic metres; 4 deaths|
||M Creek/Howe Sound
||20 000 cubic metres of debris; 10 deaths|
||Alberta Creek/Howe Sound
||15 000 cubic metres of debris; 2 deaths|
||Heavy rain; 3 deaths|
||Wahleach/Lower Fraser Valley
||60 million cubic metres, $25 million on engineering controls|
||Rock slide, slump
||Millions spent to control more than 2 billion cubic metres of rock|
|The Attachie slide of May 26, 1973 west of Fort St. John dammed the Peace River for approximately 10 hours (photo courtesy of Thurber Engineering Ltd.)|
|In 1898, the Big Slide of Quesnel destroyed homes, farms and part of a highway (photo courtesy of the Ministry of Transportation and Highways).|
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||Landslides in British Columbia was originally produced as Information Circular 1993-7 by the BC Geological Survey of the B.C. Ministry of Energy, Mines and Petroleum Resources in cooperation with the B.C. Ministry of Health, the B.C. Ministry of Transportation and Highways, the B.C. Ministry of Environment, Lands and Parks, the B.C. Ministry of Forests, the B.C. Provincial Emergency Program, and with the assistance of the Geological Survey of Canada.|
Copies are available from:
BC Geological Survey