===Structure===
===Structure===
The formation of The Barrier took place about 13,000 years ago when the [[Cordilleran Ice Sheet]] had retreated from higher elevations but still existed in lower valleys.{{sfn|Morison|Hickson|2023|p=476}}{{sfn|Green|1990|p=144}} During this time, an andesite lava flow was erupted from Clinker Peak and then entered Rubble Creek valley where it cooled against ice.{{sfn|Russell|Hickson|Graham|2007|pp=11, 12}} The Barrier, which reaches a thickness of at least {{convert|250|m|ft|abbr=on}} at its [[headwall]], consists of unusually thick andesite lava as a result of this impoundment.{{sfn|Wilson|Russell|2019|p=141}}{{sfn|Green|1990|p=144}} Pseudo-[[pillow lava|pillow]] jointing and irregular, radiating and horizontal [[columnar joint]]s are present in The Barrier; they are indicative of lava-ice interactions.{{sfn|Wilson|Russell|2019|p=141}}
The formation of The Barrier took place about 13,000 years ago when the [[Cordilleran Ice Sheet]] had retreated from higher elevations but still existed in lower valleys.{{sfn|Morison|Hickson|2023|p=476}}{{sfn|Green|1990|p=144}} During this time, an andesite lava flow was erupted from Clinker Peak and then entered Rubble Creek valley where it cooled against ice.{{sfn|Russell|Hickson|Graham|2007|pp=11, 12}} The Barrier, which reaches a thickness of at least {{convert|250|m|ft|abbr=on}} at its [[headwall]], consists of unusually thick andesite lava as a result of this impoundment.{{sfn|Wilson|Russell|2019|p=141}}{{sfn|Green|1990|p=144}} Pseudo-[[pillow lava|pillow]] jointing and irregular, radiating and horizontal [[columnar joint]]s are present in The Barrier; they are indicative of lava .{{sfn|Wilson|Russell|2019|p=141}}
===1855–1856 collapse===
===1855–1856 collapse===
Lava dam in British Columbia, Canada
The Barrier is a lava dam retaining the Garibaldi Lake system in southwestern British Columbia, Canada.
The Barrier is located about 80 kilometres (50 miles) north of Vancouver between the communities of Squamish and Whistler. It lies within Garibaldi Provincial Park, a more than 20,000-hectare (49,000-acre) protected area in the southern Coast Mountains. This wilderness park incorporates much of the Cheakamus River watershed and contains snow-capped mountains, diverse vegetation, iridescent waters, scenic vistas and rich geological history. The main territorial division in the area is New Westminster Land District which includes the southwestern portion of mainland British Columbia, as well as offshore islands and waterways.[8]

Garibaldi Lake on the northern side of Mount Garibaldi is the main lake impounded by The Barrier. It lies within the heart of Garibaldi Provincial Park and is fed by meltwater streams originating from glaciers. With a length of 5.23 km (3.25 mi) and a width of 2.4 km (1.5 mi), Garibaldi Lake is the largest lake in Garibaldi Provincial Park. This 250-metre-deep (820-foot) lake has a water volume of 1 km3 (0.24 mi3), a surface elevation of 1,470 m (4,820 ft) and is drained by Rubble Creek, which flows into the much smaller Lesser Garibaldi Lake.
Lesser Garibaldi Lake lies within a depression on top of The Barrier where Rubble Creek follows a subterranean channel under the volcanic dam. Rubble Creek then reappears at the foot of The Barrier in a pair of springs before flowing northwesterly through a valley to the Cheakamus River 4.5 km (2.8 mi) downstream. At times of exceptionally high water, a part of Rubble Creek flows over the surface to Barrier Lake at the northwesternmost end of The Barrier. Rubble Creek then cascades over The Barrier into the lower valley.

The Barrier is part of the Mount Price complex, which includes the 2,049 m (6,722 ft) high stratovolcano of Mount Price and the 1,983 m (6,506 ft) high stratovolcano of Clinker Peak on the western shoulder of Mount Price. This complex was formed by the eruption of lavas and pyroclastic flows during three periods of volcanic activity in the last 1.2 million years; the lavas and pyroclastic flows are of andesite and dacite composition. The Mount Price complex is the oldest eruptive centre in the Garibaldi Lake volcanic field, which also includes Cinder Cone, The Black Tusk and The Table.
Volcanism throughout the Garibaldi Lake volcanic field has produced a broader range of volcanic rocks; among them are andesite, dacite, basaltic andesite and basalt. The volcanic field is part of the Garibaldi Volcanic Belt, which includes several other volcanic fields such as the Mount Garibaldi, Mount Meager, Mount Cayley, Bridge River and Squamish fields. Volcanism in the Garibaldi Volcanic Belt, which began about three million years ago, is the result of subduction along the western continental margin of North America.
The formation of The Barrier took place about 13,000 years ago when the Cordilleran Ice Sheet had retreated from higher elevations but still existed in lower valleys. During this time, an andesite lava flow was erupted from Clinker Peak and then entered Rubble Creek valley where it cooled against ice. The Barrier, which reaches a thickness of at least 250 m (820 ft) at its headwall, consists of unusually thick andesite lava as a result of this impoundment. Pseudo-pillow jointing and irregular, radiating and horizontal columnar joints are present in The Barrier; they are indicative of lava cooling against ice.
1855–1856 collapse
[edit]

Rubble Creek boulder field
Landslides
Garibaldi Lake
Barrier Civil Defence Zone
- Anthony, Leslie (2016). “Breaking Barriers”. Pique Newsmagazine. Retrieved January 17, 2026.
- Burwash, Edward M. (1914). “Pleistocene Vulcanism of the Coast Range of British Columbia”. The Journal of Geology. 22 (3). University of Chicago Press: 260–267. Bibcode:1914JG…..22..260B. doi:10.1086/622148. S2CID 128978632.
- Davidson, John; Caverhill, P. Z.; Preble, Edward A.; Hutchinson, A. H. (1926). “British Columbia”. In Shelford, Victor E. (ed.). Naturalist’s Guide to the Americas. Williams and Wilkins Company. pp. 150–168.
- “Garibaldi Lake”. BC Geographical Names. Archived from the original on November 30, 2024.
- “Garibaldi Lake”. Global Volcanism Program. Smithsonian Institution. Archived from the original on July 22, 2021.
- “Garibaldi Park”. BC Geographical Names. Archived from the original on April 25, 2025.
- “Garibaldi Park”. BC Parks. Archived from the original on January 15, 2026.
- Green, Nathan (1990). Wood, Charles A.; Kienle, Jürgen (eds.). Volcanoes of North America: United States and Canada. Cambridge University Press. ISBN 0-521-43811-X.
- Green, Nathan L.; Armstrong, Richard L.; Harakal, J. E.; Souther, J. G.; Read, Peter B. (1988). “Eruptive History and K-Ar Geochronology of the Late Cenozoic Garibaldi Volcanic Belt, Southwestern British Columbia”. Geological Society of America Bulletin. 100 (4). Geological Society of America: 563–579. doi:10.1130/0016-7606(1988)100<0563:EHAKAG>2.3.CO;2. ISSN 0016-7606.
- Kelman, Melanie C.; Wilson, Alexander M. (2024). “Assessing the Relative Threats from Canadian Volcanoes”. Canadian Journal of Earth Sciences. 61 (3). Canadian Science Publishing: 408–430. doi:10.1139/cjes-2023-0074. ISSN 0008-4077.
- Locher, Peter; Berna, Francesco (2014). “Holocene Human Interaction and Adaptation to Geological and Climatic Changes in the Lower Mainland, Fraser Canyon, and Coast Mountain Area of British Columbia: A Geoarchaeological View”. In Dashtgard, Shahin; Ward, Brent (eds.). Trials and Tribulations of Life on an Active Subduction Zone: Field Trips in and Around Vancouver, Canada. GSA Field Guide. Vol. 38. Geological Society of America. doi:10.1130/2014.0038(04). ISBN 978-0-8137-0038-0.
- Madsen, J. K.; Thorkelson, D. J.; Friedman, R. M.; Marshall, D. D. (2006). “Cenozoic to Recent Plate Configurations in the Pacific Basin: Ridge Subduction and Slab Window Magmatism in Western North America”. Geosphere. 2 (1). Geological Society of America: 11–34. doi:10.1130/GES00020.1. ISSN 1553-040X.
- Maybank, Blake; Mertz, Peter (2002). The National Parks and Other Wild Places of Canada. Barron’s Educational Series. ISBN 978-0764154225.
- Moore, D. P.; Mathews, W. H. (1978). “The Rubble Creek Landslide, Southwestern British Columbia”. Canadian Journal of Earth Sciences. 15 (7). NRC Research Press: 1039–1052. doi:10.1139/e78-112. ISSN 0008-4077.
- Morison, Conner A. G.; Hickson, Catherine J. (2023). “Mount Garibaldi: Hazard Potential from a Long-Dormant Volcanic System in the Pacific Northwest”. Canadian Journal of Earth Sciences. 60 (5). Canadian Science Publishing: 464–484. doi:10.1139/cjes-2022-0067. ISSN 0008-4077.
- “New Westminster Land District”. BC Geographical Names. Archived from the original on January 20, 2025.
- Russell, James K.; Edwards, Benjamin R.; Williams-Jones, Glyn; Hickson, Catherine J. (2023). “Pleistocene to Holocene Volcanism in the Canadian Cordillera”. Canadian Journal of Earth Sciences. 60 (10). Canadian Journal of Earth Sciences: 1443–1466. doi:10.1139/cjes-2023-0065. ISSN 0008-4077.
- Russell, J. K.; Hickson, C. J.; Andrews, Graham (2007). “Canadian Cascade Volcanism: Subglacial to Explosive Eruptions Along the Sea to Sky Corridor, British Columbia”. In Stelling, Pete; Tucker, David S. (eds.). Floods, Faults, and Fire: Geological Field Trips in Washington State and Southwest British Columbia. GSA Field Guides. Vol. 9. Geological Society of America. pp. 1–29. doi:10.1130/2007.fld009(01). ISBN 978-0813700090.
- “Squamish”. Global Volcanism Program. Smithsonian Institution. Archived from the original on October 17, 2025.
- “The Barrier”. BC Geographical Names. Archived from the original on April 1, 2025.
- Mathews, W. H. (1956). “Physical Limnology and Sedimentation in a Glacial Lake”. Geological Society of America Bulletin. 67 (5). Geological Society of America: 537–552. doi:10.1130/0016-7606(1956)67[537:PLASIA]2.0.CO;2.
- Wilson, A. M.; Russell, J. K. (2019). “Quaternary Glaciovolcanism in the Canadian Cascade Volcanic Arc – Paleoenvironmental Implications”. In Poland, Michael P.; Garcia, Michael O.; Camp, Victor E.; Grunder, Anita (eds.). Field Volcanology: A Tribute to the Distinguished Career of Don Swanson. GSA Special Papers. Vol. 538. Geological Society of America. pp. 133–157. doi:10.1130/2018.2538(06). ISBN 978-0813795386. S2CID 214521258.



