Editing Mount Garibaldi (section)

===Volcanic hazards===
[[File:Trips 03 - Brandywine - Mt Garibaldi (4435874720).jpg|thumb|right|alt=Snow-covered mountains rising over hilly vegetated terrain.|Mount Garibaldi with Mount Price and Clinker Peak in the left-centre]]
[[File:GaribaldiPP-MountGaribalidi.jpg|thumb|right|alt=A snow-covered, cone-shaped mountain overlooking snow-covered and exposed slopes.|Mount Garibaldi as seen from the north-northeast]]
Mount Garibaldi is one of two volcanoes in Canada classified as a very high threat by [[Natural Resources Canada]], the other volcano being Mount Meager {{Convert|95|km|mi|abbr=off}} to the northwest.<ref>{{cite report|last1=Wilson|first1=Alexander M.|last2=Kelman|first2=Melanie C.|title=Assessing the Relative Threats from Canadian Volcanoes|series=Geological Survey of Canada, Open File 8790|pages=32, 34, 50|publisher=[[Natural Resources Canada]]|year=2021|doi=10.4095/328950|doi-access=free}}</ref> Although [[Plinian eruption]]s have not been identified at Mount Garibaldi, Peléan eruptions can also produce large amounts of volcanic ash that could significantly affect the nearby communities of Whistler and Squamish. Peléan eruptions might cause short and long term water supply problems for the city of Vancouver and most of the Lower Mainland. The catchment area for the [[Metro Vancouver watersheds|Greater Vancouver watershed]] is downwind from Mount Garibaldi. An eruption producing floods and [[lahar]]s could destroy parts of [[British Columbia Highway 99|Highway 99]], threaten communities such as [[Brackendale, British Columbia|Brackendale]] and endanger water supplies from [[Pitt Lake]]. Fisheries on the Pitt River would also be at risk.<ref name="HC"/> Mount Garibaldi is also close to a major [[airway (aviation)|air traffic route]]; volcanic ash reduces visibility and can cause jet engine failure, as well as damage to other aircraft systems.<ref>{{cite web|url=http://gsc.nrcan.gc.ca/volcanoes/haz_e.php|title=Volcanic Hazards|work=Volcanoes of Canada|publisher=[[Natural Resources Canada]]|date=2009-04-02|access-date=2022-04-09|url-status=dead|archive-url=https://web.archive.org/web/20090202075315/http://gsc.nrcan.gc.ca/volcanoes/haz_e.php|archive-date=February 2, 2009}}</ref><ref>{{cite web|last1=Neal|first1=Christina A. |author-link1=Christina Neal |last2=Casadevall|first2=Thomas J.|last3=Miller|first3=Thomas P.|last4=Hendley II|first4=James W.|last5=Stauffer|first5=Peter H.|title=Volcanic Ash–Danger to Aircraft in the North Pacific|publisher=[[United States Geological Survey]]|date=2004-10-14|url=https://pubs.usgs.gov/fs/fs030-97/|access-date=2022-04-09|url-status=live|archive-url=https://web.archive.org/web/20210718085637/https://pubs.usgs.gov/fs/fs030-97/|archive-date=2021-07-18}}</ref> These volcanic hazards become more serious as the Lower Mainland grows in population.<ref name="HC"/>

At the head of the Cheekye River are several fractures and linear scarps that face up-slope. These features, referred to as the Cheekye linears, occur in pyroclastic rocks and interbedded andesitic and dacitic flows on the slopes of Brohm and Alice ridges. They may have formed as a result of sliding of this volcanic sequence along its [[Contact (geology)|contact]] with the underlying basement rocks.<ref name="KG">{{cite journal|last1=Clague|first1=John J.|last2=Friele|first2=Pierre|last3=Hutchinson|first3=Ian|title=Chronology and Hazards of Large Debris Flows in the Cheekye River Basin, British Columbia, Canada|journal=Environmental & Engineering Geoscience|publisher=[[Association of Environmental & Engineering Geologists]]|pages=100, 101|year=2003|volume=9|issue=2|doi=10.2113/9.2.99|bibcode=2003EEGeo...9...99C |issn=1558-9161}}</ref> As a result, the Cheekye linears pose potential landslide hazards to Brackendale and several [[Squamish Nation]] villages nearby.<ref name="KG"/><ref name="OB">{{cite web|last1=Ritchie|first1=Haley|url=https://www.vancouverisawesome.com/courier-archive/real-estate/huge-squamish-mixed-use-development-takes-next-step-3080141|title=Huge Squamish Mixed-use Development Takes Next Step|website=Vancouver Is Awesome|publisher=[[Glacier Media]]|year=2018|access-date=2022-04-14}}</ref> The danger of catastrophic landslides from Mount Garibaldi has restricted development on the Cheekye Fan.<ref name="KG"/> In 2018, a major development on the Cheekye Fan was approved by Squamish council. The project included 537&nbsp;single-family units, 678&nbsp;multi-unit dwellings and a $45 million debris flow barrier to prevent a large landslide from reaching the Cheekye Fan.<ref name="OB"/>

Because dacite is the main type of lava erupted from Mount Garibaldi, lava flows are a low to moderate hazard.<ref name="HLK"/> Dacite is [[felsic]]{{efn|Felsic pertains to magmatic rocks that are enriched with silicon, oxygen, [[aluminum]], [[sodium]] and [[potassium]].<ref name="Pinti2011">{{Citation|last=Pinti|first=Daniele|date=2011|encyclopedia=Encyclopedia of Astrobiology|page=938|publisher=[[Springer Berlin Heidelberg]]|doi=10.1007/978-3-642-11274-4_1893|isbn=978-3-642-11271-3|chapter=Mafic and Felsic}}</ref>}} in composition, containing 62–69% silica content.<ref>{{cite book|last1=Tran|first1=Trong-Hoa|last2=Polyakov|first2=Gleb V.|last3=Tran|first3=Tuan-Anh|last4=Borisenko|first4=Alexander S.|last5=Izokh|first5=Andrey E.|last6=Balkin|first6=Pavel A.|last7=Ngo|first7=Thi-Phuong|last8=Pham|first8=Thi-Dung|title=Intraplate Magmatism and Metallogeny of North Vietnam|series=Modern Approaches in Solid Earth Sciences|year=2016|publisher=[[Springer International Publishing]]|page=121|isbn=978-3-319-25233-9}}</ref><ref>{{cite web|title=Volcano Hazards Program Glossary|publisher=[[United States Geological Survey]]|url=https://www.usgs.gov/glossary/volcano-hazards-program-glossary|archive-url=https://web.archive.org/web/20220411121546/https://www.usgs.gov/glossary/volcano-hazards-program-glossary|archive-date=2022-04-11|url-status=live}}</ref> This high percentage in silica content increases the viscosity of dacitic melts relative to that of andesite or [[basalt]], generally resulting in the formation of steep-sided lava domes and stubby lava flows.<ref>{{cite web|title=Lava Flows Destroy Everything in Their Path|publisher=[[United States Geological Survey]]|url=https://www.usgs.gov/natural-hazards/volcano-hazards/lava-flows-destroy-everything-their-path|archive-url=https://web.archive.org/web/20210705104634/https://www.usgs.gov/natural-hazards/volcano-hazards/lava-flows-destroy-everything-their-path|archive-date=2021-07-05|url-status=live}}</ref><ref>{{cite book|last1=Gill|first1=Robin|title=Igneous Rocks and Process: A Practical Guide|year=2010|publisher=[[Wiley-Blackwell]]|page=169|isbn=978-0-632-06377-2|doi=}}</ref> An exception is the {{Convert|15|km|mi|adj=mid|-long|abbr=off}} Ring Creek dacite flow from Opal Cone, a length that is normally attained by basaltic lava flows.<ref name="HC"/>