New maps have been created for the Twin Harbors coast that show emergency tsunami safety routes.
The maps were created as part of the Washington State Department of Natural Resources’ (DNR) efforts to provide tsunami safety information to communities along the Washington coast.
Geologists have modeled and published the maps showing the estimated time to take shelter in the event of a tsunami produced by a major earthquake in the Cascadia subduction zone.
Knowing where to walk and how long it will take to get there could be one of the most important pieces of information for anyone in coastal communities when a tsunami hits.
The construction of a vertical evacuation structure by the Shoalwater Bay Indian Tribe has allowed residents of the 3-mile-long Tokeland Peninsula to reach safety during the next tsunami.
“It is essential that our coastal communities know what to do and where to go before the next tsunami hits,” said Public Lands Commissioner Hilary Franz. “I am extremely grateful for the Shoalwater Bay Tribe’s commitment to making everyone on the Tokeland Peninsula safer, providing people with refuge when they need it. The Auntie Lee Escape Tower will save lives, and I hope it will serve as a model for other communities along the coast where our geologist discovered there wasn’t enough time to walk to to safety when – not if – the next tsunami arrives.
On the Tokeland Peninsula, the construction of the Auntie Lee Vertical Escape Tower has reduced what was a 90-minute walk to just 15 minutes.
According to DNR models, tsunami waves produced by a magnitude 9 earthquake on the Cascadia subduction zone would be about 17 feet high and arrive about 35 minutes after the earthquake.
On August 5, the Shoalwater Bay Indian Tribe dedicated the Auntie Lee Vertical Escape Tower.
The tower is the third vertical evacuation structure in North America, joining rooftop structures in Westport, Washington and Newport, Oregon, and can accommodate more than 400 people.
Using models of a magnitude 9 earthquake in Cascadia, the maps use colors to indicate the number of minutes it would take to walk to safety at a moderate pace in these communities.
These maps can help communities prepare for and plan for tsunami evacuation. They also highlight evacuation issues, such as locations of likely bridge failures and areas requiring evacuation structures where no elevated ground is available. The maps were produced in coordination with local emergency officials.
Waves from a Cascadia earthquake-induced tsunami could reach some coastal communities in just 15 minutes after the next mega-thrust earthquake begins. Cascadia’s last break was 322 years ago.
Templates, maps available online
New pedestrian maps and maps of other communities are available via an interactive map on the MNR website: https://www.dnr.wa.gov/programs-and-services/geology/geologic-hazards/tsunamis#tsunami-evacuation-maps
The interactive map also provides access to tsunami evacuation brochures for areas that do not yet have walking time maps.
Additional information on the impacts of earthquakes on communities in Washington is available on the MNR Geological Information Portal at: https://geologyportal.dnr.wa.gov