When it comes to tsunami preparedness, coastal communities must adapt to their unique geographies and resources to protect residents and visitors. In this post, I compare two towns with different approaches to managing tsunami risks: Seaside, Oregon, and Westport, Washington. Using data from the Oregon Department of Geology and Mineral Industries (DOGAMI) for Seaside and external maps for Westport, I created feature maps highlighting their respective tsunami inundation zones and evacuation strategies.
Seaside, Oregon: A Community in the Crosshairs
As discussed in my previous post, Seaside is highly vulnerable to a Cascadia Subduction Zone earthquake and tsunami.
- Extensive Inundation Zones: Much of Seaside lies within the “XXL” tsunami inundation zone, leaving critical infrastructure like hospitals, older schools, and bridges at risk.
- Limited high ground: There are few natural high-ground areas within a short distance, complicating evacuation efforts.
- Reliance on horizontal evacuation: Residents must travel inland to reach safety, a daunting task given the short evacuation window of 15-20 minutes.
- Outdated construction laws: Although it has been illegal for decades to build hospitals, schools, firehouses, and police stations inside the inundation zone, those which were already within it could stay, and any other new construction is permissible – including but not limited to: energy facilities, hotels, and retirement homes. In these cases, builders are required only to consult with DOGAMI about evacuation plans.
However, recent efforts show progress in addressing these risks:
- New school built outside the Inundation Zone: Seaside has taken a significant step by constructing a new school outside the tsunami inundation zone, ensuring that students and staff have a safe location during an event.
- Evacuation maps available: Residents now have access to detailed evacuation maps, which improve awareness and preparedness.
Westport, Washington: A Model for Vertical Evacuation
In contrast, Westport, Washington, has made strides in tsunami preparedness through innovative solutions:
- Vertical evacuation structure: Westport boasts the first vertical evacuation structure in the United States, built atop Ocosta Elementary School. This structure provides immediate refuge for hundreds of residents and students.
- Proximity to high ground: Westport benefits from more natural high-ground areas nearby, reducing the reliance on long evacuation routes.
- Comprehensive evacuation maps: Washington State’s tsunami evacuation maps showcase detailed routes and assembly areas, making it easier for residents to understand their options.
Mapping Westport: Challenges and Insights
To create a comparable feature map for Westport, I referred to tsunami evacuation maps provided by Washington State’s Department of Natural Resources (DNR). Since the DOGAMI dataset only covers the Oregon coast, I:
- Downloaded PDFs from the Washington DNR’s official website.
- Digitized Westport’s tsunami inundation zones, location of critical infrastructure, and the vertical evacuation structure onto a single map.
- Compared Westport’s evacuation infrastructure with Seaside’s, focusing on accessibility and safety.
Lessons Learned
The contrast between Seaside and Westport reveals important lessons for tsunami preparedness:
- Westport’s vertical evacuation structure is a possible game-changer for communities with limited high ground. Whether similar structures would be a sound solution for other communities like Seaside remains an area for further research.
- Access to detailed evacuation maps, like those provided by Washington DNR and DOGAMI, empowers residents to make informed decisions.
- Westport’s foresight in building innovative infrastructure highlights the importance of long-term investment in disaster resilience.