The greatest hazard facing the Oregon coast is a Cascadia Subduction Zone (CSZ) earthquake and tsunami which could occur at any time. It is important that all Oregonians understand and are prepared for this hazard. The Oregon Coastal Management Program (OCMP), administered by DLCD, is coordinating with coastal communities to help them prepare for a local CSZ tsunami through land use planning.
From 2016 through 2021, OCMP conducted a project with many coastal cities and counties focused on reducing the potential negative impacts of a tsunami through local mapping, the adoption of Tsunami Hazard Overlay Zones, development of Tsunami Evacuation Facility Improvement Plans (TEFIPs), and more. The resources posted here are the results of this work. Coastal cities and counties who have not yet done this type of planning can benefit from these lessons learned and plan for tsunami resilience in their own communities.
Tsunami Mapping
Maps from the Oregon Department of Geology and Mineral Industries (DOGAMI) are the best source of information for identifying areas that may be subject to tsunami inundation. DOGAMI has produced several maps depicting tsunami inundation for the Oregon coast, all of which can be found on their
Tsunami Clearinghouse webpage.
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Tsunami Inundation Maps (TIMs) depict the projected tsunami inundation zone from five different seismic events and their resulting tsunamis: small, medium, large, extra-large, or extra extra-large (S, M, L, XL, XXL). These models show the changes in risk of tsunami inundation compared to the size of the event.
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Tsunami Evacuation Maps are public products designed to direct visitors and residents away from low-lying areas in the event of a tsunami. They depict three color zones: orange for the largest expected distant tsunami (an earthquake occurs elsewhere but we receive a tsunami); yellow for the largest expected local tsunami (from a CSZ earthquake); and green for safety (or high ground). These maps are available through brochures, an online viewer, and a phone app. You can also print a brochure for a specific area of interest.
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Beat the Wave Tsunami Evacuation Routes show areas of expected tsunami inundation, the most efficient routes to reach safety, and how fast one must travel to get there. DOGAMI completed detailed tsunami evacuation modeling for most coastal communities to determine the best routes to "beat the wave" to safety for a local tsunami event.
These maps allow communities and planners to understand the risk and vulnerability to a local tsunami event. With this information, they can look for ways to improve evacuation and implement land use strategies to improve community resilience. Visit
www.oregontsunami.org for more information about maps and map products available for your area.
Tsunami Land Use Work
All coastal cities and counties are encouraged to adopt tsunami resilience land use regulations created to fit their community needs. This kind of land use planning can influence where and how people build or use land over time. When tsunami hazards are considered and understood as communities develop, both short- and long-term resilience can improve.
OCMP created a
Tsunami Land Use Guide that provides model code and comprehensive plan policy language as a starting point. It is important to note that the model code does not apply to single family homes on existing lots or parcels, nor does it apply to existing development.
The provisions suggested in the Land Use Guide focus on three main areas:
- Building new critical and special occupancy buildings, such as hospitals, police and fire stations, schools, and large gathering facilities away from areas at high risk for tsunami inundation, labeled as “Large” or "Medium" tsunami inundation zones on DOGAMI maps. This is to allow those buildings and services to function post-event. There is a “Use Exception” process to allow critical and special occupancy buildings to be permitted in the tsunami inundation zone based on specific criteria.
- Require new land divisions within areas at higher risk of tsunami inundation to include evacuation improvements in their overall development design, such as evacuation route signs, educational materials, or pedestrian pathways. This is to help ensure evacuation success to the maximum possible extent.
- Provide an optional permit process to allow a development proposal to flex code standards to achieve higher degrees of risk reduction than required. This process could waive standards such as density requirements, height limitations, or setbacks. For example, this permit could waive height limitations for a hotel that is built as a vertical evacuation structure. Alternatively, the permit could waive setbacks or other development standards to allow developments to be clustered outside of a tsunami inundation zone. This process is similar in concept to flexibilities for planned developments.
Land Use Planning Resources
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Tsunami Land Use Guide – provides a path for communities to address tsunami risk through tailored land use planning. The guide includes:
- Sample comprehensive plan policies for Goal 7: Areas Subject to Natural Hazards, Goal 11: Public Facilities and Services, Goal 12: Transportation, and Goal 14: Urbanization for coastal communities
- Model code for a Tsunami Hazard Overlay Zone (THOZ) which can be tailored to meet a community's risk tolerance
- Steps to develop a Tsunami Evacuation Facilities Improvement Plan (TEFIP)
- Financing and incentive concepts, such as how to finance evacuation improvements
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How to Implement Goal 7: Areas Subject to Natural Hazards – fact sheet about the post-acknowledgement plan amendment process a community can use to integrate new natural hazard data into their land use program.
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Tsunami building code standards – As a result of the 2021 Legislative Session, there are now building code requirements for certain types of critical and essential facilities that are built within the tsunami inundation zone as
mapped by the American Society of Civil Engineers. These rules are different, but related, to any tsunami land use regulations in a local community.
Examples of Tsunami Planning in Oregon
Utilize and learn from the good work of others! Communities listed below, from north to south, have partnered with DLCD in tsunami resilience planning. Check out a selection of plans, maps, fact sheets, notices, and other resources, which may be useful for your community. Many communities, businesses, and organizations on the Oregon coast are working to prepare for a CSZ earthquake and tsunami. These projects are focused on land use planning work done with DLCD through two federally funded grants.
Gearhart
Rockaway Beach
Tillamook County
Manzanita
Lincoln City
Newport
North Bend
Port Orford
Coastwide
Many of the coastal communities doing this work received a technical assistance grant from OCMP. Learn more on our
Coastal Grants webpage.
Funding for this important work was made possible through grants from the National Oceanic and Atmospheric Administration's (NOAA)
Office for Coastal Management and
National Tsunami Hazard Mitigation Program.
Learn more about
earthquake and tsunami hazards.
Learn more about
natural hazard mitigation planning.