Editing Lower Mainland (section)

==Natural threats==

===Flooding===
The Lower Mainland is considered to have a high vulnerability to flood risk. There have been two major region-wide floods in [[Fraser River#1894 flood|1894]] and [[Fraser River flood of 1948|1948]], both associated with an extreme [[Freshet|spring freshet]] of the [[Fraser River]].<ref>{{cite web|title=Flood History|publisher=Flood Wise|url=https://floodwise.ca/flood-101/flood-history/|quote=The Lower Mainland has experienced two major Fraser River floods in just the past 130 years. The largest flood on written record was in 1894, and the second largest was in 1948. Earlier large-scale floods are also part of the oral history of Coast Salish First Nations.|access-date=29 November 2021|archive-date=30 November 2021|archive-url=https://web.archive.org/web/20211130011811/https://floodwise.ca/flood-101/flood-history/|url-status=live}}</ref><ref>{{cite web|title=From the Archives: The 1894 and 1948 Fraser Valley floods|publisher=Vancouver Sun|url=https://vancouversun.com/news/local-news/from-the-archives-the-1894-and-1948-fraser-valley-floods|date=17 November 2021|access-date=29 November 2021|archive-date=30 November 2021|archive-url=https://web.archive.org/web/20211130013714/https://vancouversun.com/news/local-news/from-the-archives-the-1894-and-1948-fraser-valley-floods|url-status=live}}</ref><ref>{{cite web|title=This Week in History: 1894 & 1948 The Fraser Valley is inundated in a great flood|publisher=Vancouver Sun|url=https://vancouversun.com/news/this-week-in-history-1894-1948-the-fraser-valley-is-inundated-in-a-great-flood|date=19 November 2021|access-date=29 November 2021|archive-date=30 November 2021|archive-url=https://web.archive.org/web/20211130011810/https://vancouversun.com/news/this-week-in-history-1894-1948-the-fraser-valley-is-inundated-in-a-great-flood|url-status=live}}</ref> Other major floods in the Lower Mainland{{Snd}}including June 1972,<ref>{{cite web|title=Flooding events in Canada: British Columbia|publisher=Government of Canada|url=https://www.canada.ca/en/environment-climate-change/services/water-overview/quantity/floods/events-british-columbia.html|quote=On June 16, the lower Fraser peaked at Hope, with a maximum instantaneous flow of 3400 cubic metres per second and a maximum elevation of 7.1 metres, well above the danger level of 6.1 metres.|date=2 December 2010|access-date=29 November 2021|archive-date=30 November 2021|archive-url=https://web.archive.org/web/20211130011813/https://www.canada.ca/en/environment-climate-change/services/water-overview/quantity/floods/events-british-columbia.html|url-status=live}}</ref><ref>{{cite web|title=River flooding part of Hope history|publisher=Hope Standard|url=https://www.hopestandard.com/community/river-flooding-part-of-hope-history/|quote=In 1972, the Fraser River again experienced record flood waters – the second highest in recorded times with a discharge of 12,900 cubic metres per second and a maximum height of 10.141 meters at Hope on June 16. Wardle Street and part of Seventh Avenue were submerged, and on Tom Berry Road 10 houses were flooded and families were forced to evacuate their properties. Pumps were brought in to remove water and residents were able to return home after approximately a week.|date=27 June 2012|access-date=29 November 2021|archive-date=30 November 2021|archive-url=https://web.archive.org/web/20211130011815/https://www.hopestandard.com/community/river-flooding-part-of-hope-history/|url-status=live}}</ref> November 1990,<ref>{{cite web|title=The Fraser River doesn't pose the only flood threat to Abbotsford|publisher=The Abbotsford News|url=https://www.abbynews.com/news/the-fraser-river-doesnt-pose-the-only-flood-threat-to-abbotsford/|quote=A Nooksack flood in 1990 swamped the Whatcom Road interchange and western portions of Sumas Prairie. Such a flood is expected to take place every 35 years or so. There are worries that a larger flood event would change the course of the river entirely, diverting it north into the channel of the much-smaller Sumas River.|date=17 May 2018|access-date=29 November 2021|archive-date=30 November 2021|archive-url=https://web.archive.org/web/20211130011811/https://www.abbynews.com/news/the-fraser-river-doesnt-pose-the-only-flood-threat-to-abbotsford/|url-status=live}}</ref><ref>{{cite web|title=Group tasked with preventing major Fraser Valley flood hasn't met in seven years|publisher=Today In BC|url=https://www.todayinbc.com/news/group-tasked-with-preventing-major-fraser-valley-flood-hasnt-met-in-seven-years/|quote=In 1990, the Nooksack River in northern Washington overflowed its banks, with its waters flooding over the border and into Sumas Prairie. The flood cut off Highway 1, and also inundated the towns of Everson and Sumas.|date=3 September 2018|access-date=29 November 2021|archive-date=30 November 2021|archive-url=https://web.archive.org/web/20211130011811/https://www.todayinbc.com/news/group-tasked-with-preventing-major-fraser-valley-flood-hasnt-met-in-seven-years/|url-status=live}}</ref> and November 2021{{Snd}}have been more localized, primarily impacting areas in the Fraser Valley like the [[Sumas Prairie]], with comparatively minor impacts to Metro Vancouver. Prior to the 2021 flood, according to the Fraser Basin Council, scientists predicted a one-in-three chance of a similar-sized flood occurring in the next 50 years.<ref>{{cite web |title=Flood Hazard Management on the Fraser River |publisher=Fraser Basin Council |url=http://www.fraserbasin.bc.ca/programs/flood.html#risk |access-date=18 June 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080626142044/http://www.fraserbasin.bc.ca/programs/flood.html#risk |archive-date=26 June 2008}}</ref>

In the second quarter of 2007, the Lower Mainland was on high alert for flooding. Higher than normal snow packs in the [[British Columbia Interior]] prompted municipal governments to start taking emergency measures in the region. [[Dike (construction)|Dikes]] along the Fraser River are regulated to handle approximately {{Convert|8.5|m}} at the Mission Gauge (the height above sea level of the dykes at Mission). Warmer than normal weather in the province's Interior region caused large amounts of snow to melt prematurely, resulting in higher-than-normal water levels, which, nevertheless, remained well below flood levels.<ref>{{cite news |title=Fraser Valley prepares for possible flooding |publisher=CBC News |date=5 June 2007 |url=https://www.cbc.ca/news/canada/british-columbia/fraser-valley-prepares-for-possible-flooding-1.648037 |access-date=24 June 2007 |url-status=live |archive-url=https://web.archive.org/web/20070709215645/https://www.cbc.ca/news/canada/british-columbia/fraser-valley-prepares-for-possible-flooding-1.648037 |archive-date=9 July 2007}}</ref><ref>Nguyen, Linda (7 June 2007). [http://www.canada.com/vancouversun/story.html?id=570b533b-65a6-438c-813a-04f5a4c4ec89 Lower Mainland at flood risk for weeks yet] {{webarchive|url=https://web.archive.org/web/20070626080216/http://www.canada.com/vancouversun/story.html?id=570b533b-65a6-438c-813a-04f5a4c4ec89 |date=26 June 2007}}. ''Vancouver Sun.'' Retrieved on: 18 June 2008.</ref>

Flooding can cover much of the Lower Mainland. [[Cloverdale, Surrey|Cloverdale]], [[Barnston Island]], low-lying areas of [[Maple Ridge, British Columbia|Maple Ridge]], areas west of [[Hope, British Columbia|Hope]], [[White Rock, British Columbia|White Rock]], [[Richmond, British Columbia|Richmond]], parts of [[Vancouver]], and parts of [[Surrey, British Columbia|Surrey]] are potentially at risk. In 2007, the Lower Mainland was largely spared, although northern regions of the province, along the [[Skeena River|Skeena]] and [[Nechako River|Nechako]] Rivers, experienced floods. [[Climatology|Climate scientists]] predict that increasing temperatures will mean wetter winters and more snow at the high elevations. This will increase the likelihood of snowmelt floods.<ref>{{cite news |last=Drake |first=Laura |title=Flooding in future may be more frequent, scientists say |newspaper=Globe and Mail |date=16 June 2007 |url=https://www.theglobeandmail.com/servlet/story/LAC.20070616.BCFLOOD16/TPStory/TPNational/BritishColumbia/  | access-date=24 June 2007}}</ref>

The provincial government maintains an integrated flood hazard management program and extensive flood protection infrastructure in the Lower Mainland. The infrastructure consists of dikes, [[pump station]]s, floodboxes, [[riprap]], and [[relief well]]s.<ref>{{cite web |author=Ministry of Environment |title=Lower Mainland Dike and Emergency Maps |url=http://www.env.gov.bc.ca/wsd/public_safety/flood/maps.html#emergmaps |access-date=24 June 2007 |url-status=dead |archive-url=https://web.archive.org/web/20070620191654/http://www.env.gov.bc.ca/wsd/public_safety/flood/maps.html#emergmaps |archive-date=20 June 2007}}</ref>

===Earthquakes===
While [[earthquake]]s are common in British Columbia and adjacent coastal waters, most are minor in energy release or are sufficiently remote to have little effect on populated areas. Nevertheless, earthquakes with a magnitude of up to 7.3 have occurred within {{Convert|150|km}} of the Lower Mainland.

Based on geological evidence, however, stronger earthquakes appear to have occurred at approximately 600-year intervals. Therefore, there is a probability that there will be a major earthquake in the region within the next 200 years.<ref name="eqplan">British Columbia. Provincial Emergency Program. (1999). [http://www.pep.bc.ca/hazard_plans/eqplan99/eqplan99-x2.html British Columbia Earthquake Response Plan, Appendix 2-The Earthquake Threat] {{webarchive|url=https://web.archive.org/web/20081113110254/http://www.pep.bc.ca/hazard_plans/eqplan99/eqplan99-x2.html |date=13 November 2008}}. {{ISBN|0-7726-3924-8}}. Retrieved on: 7 April 2008.</ref>

In April 2008, the [[United States Geological Survey]] released information concerning a newly found [[Fault (geology)|fault]] south of downtown [[Abbotsford, British Columbia|Abbotsford]], called the Boulder Creek Fault. Scientists now believe this fault is [[Active fault|active]] and capable of producing earthquakes in the 6.8 magnitude range.<ref>[https://archive.today/20120903164840/http://www.mcclatchydc.com/science/v-print/story/34512.html McClatchy Washington Bureau]. Earthquake risk. Retrieved on 12 May 2009.</ref>

===Volcanoes===
Much of the Lower Mainland is vulnerable to [[explosive eruption]]s from the [[Garibaldi Volcanic Belt]]. Volcanoes in this zone are capable of producing large quantities of [[volcanic ash]] that may cause short and long term water supply problems for Lower Mainland communities.<ref>{{cite web |publisher=[[Natural Resources Canada]] |url=http://gsc.nrcan.gc.ca/volcanoes/cat/feature_garibaldi_e.php |title=Garibaldi volcanic belt: Garibaldi Lake volcanic field |work=Catalogue of Canadian volcanoes |date=1 April 2009 |access-date=26 May 2018 |url-status=dead |archive-url=https://web.archive.org/web/20080513070258/http://gsc.nrcan.gc.ca/volcanoes/cat/feature_garibaldi_e.php |archive-date=13 May 2008}}</ref> All airports covered by the accompanying [[eruption column]] would be closed, heavy [[pyroclastic fall|ash falls]] would damage electrical equipment and weak structures could collapse under the weight of the ash.<ref>{{citation |last1=V. Stasiuk |first1=Mark |last2=J. Hickson |first2=Catherine |last3=Mulder |first3=Taimi |journal=Natural Hazards |title=The Vulnerability of Canada to Volcanic Hazards |publisher=[[Kluwer Academic Publishers]] |volume=28 |page=580 |year=2003 |issue=2/3 |doi=10.1023/A:1022954829974 |s2cid=129461798 |issn=0921-030X}}</ref>