To: Board of Supervisors
From: Sheriff-Coroner
Meeting Date: February 23, 2021
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Department Contact: |
Matthew Kendall |
Phone: |
463-4085 |
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Department Contact: |
Brentt Blaser |
Phone: |
463-5667 |
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Item Type: Regular Agenda |
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Time Allocated for Item: 15 mins |
Agenda Title:
title
Discussion and Possible Action Including the Adoption of Resolution Recognizing the Necessity of Updated Tsunami Inundation Maps and Adopting Them for Local Planning Use; and Receive a Presentation from the Redwood Coast Tsunami Work Group, California Geological Survey and California Governor’s Office of Emergency Services
(Sponsor: Sheriff-Coroner)
End
Recommended Action/Motion:
recommendation
Adopt Resolution recognizing the necessity of updated tsunami inundation maps and adopting them for local planning use; receive a presentation from the Redwood Coast Tsunami Work Group, California Geological Survey and California Governor’s Office of Emergency Services; direct the Clerk of the Board to return a certified copy of the attached resolution to the Sheriff’s Office of Emergency Services; and authorize Chair to sign same.
End
Previous Board/Board Committee Actions:
None.
Summary of Request:
Before the BOS today is a resolution adopting the newly updated Mendocino County tsunami inundation maps for local use in evacuation and public safety planning.
The California Tsunami Program, led by the California Governor’s Office of Emergency Services and the California Geological Survey, is responsible for updating the state’s tsunami inundation maps for evacuation planning and public safety. Communities use the State inundation maps to develop and update their evacuation maps and local response plans.
The State completed the current statewide tsunami inundation maps in 2009. Based on more recent information from tsunamis that have occurred since 2009, the State has determined that an update of the 2009 maps is warranted to protect the public from tsunami hazards.
The Tsunami Hazard Evacuation Maps for Emergency Planning are a new product from the State of California and are based on the Redwood Coast Tsunami Work Group (RCTWG) tsunami hazard map brochures first published in 2010. These new maps were produced via a process led by the RCTWG mapping subcommittee and have been vetted by emergency managers, first responders, and other important local stakeholders.
Are the existing 2009 tsunami inundation maps and related evacuation maps inaccurate or inadequate?
• The existing maps accurately capture the tsunami hazard from most major tsunamis from local and distant source threats.
• There are multiple reasons for the update: 1) to develop more precise tsunami hazard maps incorporating new information; 2) to follow national guidance on updating maps every 5 to 10 years; and 3) to provide more conservative, more consistent tsunami inundation maps statewide.
• Significant changes to the 2009 tsunami maps are not expected in most places.
• If significant changes are recommended, the State will work with community emergency planners to determine appropriate evacuation lines and to ensure they understand the reason for the change.
What new tsunami hazard information is available, and why is it appropriate for updating the 2009 maps?
• Over the past 10 years, tsunami science has significantly improved, with a better understanding of tsunami sources and enhancements to computer modeling.
• Tsunami events such as 2010 Chile, 2011 Japan, and 2018 Indonesia have taught scientists and planners a number of lessons about how to better plan for and respond to tsunamis.
• A new type of tsunami hazard map, the probabilistic tsunami hazard analysis (PTHA) map, represents all potential tsunami events with a 1000-year average return period, which translates to a 5 percent change of flood exceedance over a 50-year period.
• Overall, the new State tsunami inundation maps best characterize the state of tsunami science in
• California, and conservatively represent safe evacuation from all realistic tsunami events.
Alternative Action/Motion:
Return to staff for alternative handling.
Supervisorial District: All
vote requirement: Majority
Supplemental Information Available Online At: N/A
Fiscal Details:
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source of funding: N/A |
budgeted in current f/y: N/A |
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current f/y cost: N/A |
if no, please describe: |
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annual recurring cost: N/A |
revenue agreement: N/A |
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budget clarification: No cost. Funding provided by California Office of Emergency Services and California Geologic Survey |
Agreement/Resolution/Ordinance Approved by County Counsel: Yes
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CEO Liaison: Janelle Rau, Deputy CEO |
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CEO Review: Yes |
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CEO Comments:
FOR COB USE ONLY
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Executed By: Atlas Pearson, Deputy Clerk I |
Final Status:Adopted |
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Date: February 25, 2021 |
Executed Item Type: Resolution Number: 21-023 |
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