A tsunami risk presentation to Oak Bay didnB次元官网网址檛 rock the boat much as council considered the local impact of the presented scenarios.

David Forde of Associated Engineering presented council, meeting as committee of the whole on May 16, with a summary of the CRDB次元官网网址檚 2020 tsunami and flood risk assessment, which analyzed 11 scenarios and data from the Washington Geological Survey and the Oregon Department of Geology and Mineral Industry.

The focus rested on three tsunami scenarios: Cascadia Subduction Zone L1 (every 2,500 years), Cascadia Subduction Zone northern segment (every 500 to 600 years) and the DevilB次元官网网址檚 Mountain fault (every 2,000 years).

Mayor Kevin Murdoch, who said the DevilB次元官网网址檚 Mountain fault had the best name of the three, inquired how long it would take to reach Oak Bay. Forde said this scenario would need just five to 10 minutes to reach Oak Bay from across the Strait of Juan de Fuca, whereas the Cascadia Subduction Zone scenarios would take closer to an hour to arrive from their sources along coastal Washington.

B次元官网网址淭he Cascadia Subduction Zone is a much better understood seismic hazard, as well as tsunami source, relative to the DevilB次元官网网址檚 Mountain fault,B次元官网网址� Forde noted.

Murdoch emphasized the DevilB次元官网网址檚 Mountain scenario is only expected once every 2,000 years, B次元官网网址渏ust to put that into perspective.B次元官网网址�

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In the case of flooding, Forde said it helps that Oak Bay is a relatively elevated municipality, above the six-metre contour.

The area most susceptible to flooding is what Forde called the McNeill Avenue corridor, which runs about 1.25 km between McNeill Bay and the Oak Bay Marina.

B次元官网网址淭he longstanding (regional) plan used to be based on a four-metre safe elevation,B次元官网网址� Saanich Deputy Fire Chief Frank Macdonald said, adding it now falls on the district to inform the public about flood risk.

Macdonald said a digital letter of notice will be sent to residents living in what the presentation showed to be tsunami and flood-risk zones.

An educational brochure and interactive risk map of the CRD are also being crafted.

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Eileen Grant, Oak BayB次元官网网址檚 emergency program manager, explained the nature of tsunamis and local protocol for them.

B次元官网网址淭hey are quite unique and they are generally connected to earthquakes,B次元官网网址� she said. B次元官网网址淚t doesnB次元官网网址檛 just happen because the ocean moves in a unique way.B次元官网网址�

Grant said an earthquake capable of causing a tsunami could shake the area enough to knock people over. In this case, an evacuation order would already be announced and residents would want to move to safe zones, which include most of Oak Bay, besides the McNeill Avenue corridor. Residents of beachfront property would likely have to head to higher ground, she added.

B次元官网网址淭he big thing is we donB次元官网网址檛 want people to move unless they have to,B次元官网网址� Grant said, noting the traffic and chaos it would cause.

In her 10 years as program manager, she said the only change in protocol has been that residents now must plan for a seven-day evacuation period, rather than the previous three-day plan.

B次元官网网址淲e need people to understand what could happen and what they need to do in these circumstances,B次元官网网址� Grant said, adding itB次元官网网址檚 important for those living in higher-risk zones to have a grab-and-go kit ready at their door.

B次元官网网址淲eB次元官网网址檙e hoping to educate them so they know exactly what to do and whether theyB次元官网网址檙e in a yellow or green zone.B次元官网网址�

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