The Barrier is a

lava dam A volcanic dam is a type of natural dam produced directly or indirectly by volcanism, which holds or temporarily restricts the flow of surface water in existing streams, like a man-made dam. There are two main types of volcanic dams, those creat ...

retaining the

Garibaldi Lake Garibaldi Lake is a turquoise-coloured alpine lake in British Columbia, Canada, located 37 km (23 mi) north of Squamish and 19 km (12 mi) south of Whistler. The lake lies within Garibaldi Provincial Park, which features mount ...

system in southwestern

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 ...

. It is over thick and about long where it impounds the lake. The area below and adjacent to The Barrier is considered hazardous due to the unstable lava formation.

Formation

The Barrier was formed about 15,000–12,000 years ago when large lava flows emanated from Clinker Peak on the west shoulder of Mount Price. The large lava flowed towards the Cheakamus River valley. At the time of eruption, the valley was filled by glacial ice. The lava flow was stopped by the ice and ponded, eventually cooling to form an ice-marginal lava flow. When the ice melted away, the ice-cooled lava-flow front formed a precipitous cliff; water ponded behind the lava dam, forming Garibaldi Lake.

Rubble Creek boulder field

The unstable lava formation of The Barrier has in the past unleashed several

debris flow Debris flows are geological phenomena in which water-laden masses of soil and fragmented rock rush down mountainsides, funnel into stream channels, entrain objects in their paths, and form thick, muddy deposits on valley floors. They generally ...

s in the area below Garibaldi Lake. The most recent major landslide in 1855-1856 formed a large boulder field which gives Rubble Creek its name. At least of rock was removed from The Barrier during the 1855-1856 event.

Hazards

Concerns about The Barrier's instability due to volcanic, tectonic, or heavy rainfall activity prompted the provincial

government A government is the system or group of people governing an organized community, generally a state. In the case of its broad associative definition, government normally consists of legislature, executive, and judiciary. Government is ...

to declare the area immediately below it unsafe for human habitation in 1981. This led to the evacuation of the small resort village of

Garibaldi Giuseppe Maria Garibaldi ( , ;In his native Ligurian language, he is known as ''Gioxeppe Gaibado''. In his particular Niçard dialect of Ligurian, he was known as ''Jousé'' or ''Josep''. 4 July 1807 – 2 June 1882) was an Italian general, pat ...

nearby, and the relocation of residents to new recreational subdivisions away from the hazard zone. Should The Barrier completely collapse,

would be entirely released and downstream damage in the Cheakamus and

Squamish River The Squamish River is a short but very large river in the Canadian province of British Columbia. Its drainage basin is in size. The total length of the Squamish River is approximately . Course The Squamish River drains a complex of basins in the ...

s would be considerable, including major damage to the town of Squamish and possibly an impact-wave on the waters of

Howe Sound Howe Sound (french: Baie (de /d')Howe, squ, Átl'ka7tsem, Nexwnéwu7ts, Txwnéwu7ts) is a roughly triangular sound, that joins a network of fjords situated immediately northwest of Vancouver, British Columbia. It was designated as a UNESCO Biosp ...

that would reach

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest by ...

References

{{DEFAULTSORT:Barrier, The Dams in British Columbia Cliffs of Canada Volcanic dams Natural hazards in British Columbia Sea-to-Sky Corridor Garibaldi Ranges Holocene volcanism Garibaldi Lake volcanic field New Westminster Land District

Formation

Rubble Creek boulder field

Hazards

See also

References