PACIFIC COUNTY — New tsunami simulation models provide a hair-raising idea of ways in which a Cascadia Subduction Zone (CSZ) earthquake will send the ocean surging toward our coast.
The Washington State Department of Natural Resources released its south coast model Aug. 27, providing state and local agencies along with residents a glimpse of what to expect.
The new model shows that should a CSZ quake strike off the coastline, the Long Beach Peninsula would have a 15- to 20-minute window before a large-caliber tsunami would strike the area. Areas such as Tokeland would be in the same window of time. Farther away from the ocean, those near Bay Center may have up to 45 minutes. Raymond and South Bend both are anticipated to have approximately 60 to 90 minutes before being impacted.
“It’s interesting because most of the maps we’ve seen up to this point have been what DNR terms ‘get your tennis shoes wet’ maps,” Pacific County Emergency Management Agency Director Scott McDougall said.
“In some ways, the information on the new maps is worse than we expected. Where originally we had thought we would see 5 to 6 feet of water in some parts of Raymond and South Bend, that has bumped up to around 11 feet of water.
Beyond the threat of a tsunami during a CSZ quake, number one of the other major concerns is liquefaction that will likely destroy roadways during the initial quake. Areas along the Long Beach Peninsula are expected to be the most impacted. The threat of liquefaction is expected to wreak havoc of residents attempting to flee the area to move to higher ground.
“In a CSZ event, we are flat out telling people and have for a long time ‘you will not be able to drive,’” McDougall stated. “Driving is simply out of the question.”
McDougall added, “The animations are interesting because it does show pretty clearly that it’s not an entirely devastating ‘water is going to wash over everybody and wash away everybody’ event. It also highlights the fact that there are going to be many completely underwater places.”
One of the largest questions residents have had recently regarding a CSZ quake is what agencies have estimated the casualty toll could be. According to McDougall and other sources, the estimate is well into the ten thousands.
“Before we did Cascadia Rising 2016, there was an estimated casualty count for the state of Washington that was thrown out there and I am not sure they are realistic,” McDougall said. Some of the initial numbers were that 1,000 would be killed in the initial earthquake and then another 5,000 killed in the aftermath of the earthquake. I think that number is probably light. I think we are looking at a more significant number.”
Amping up preparation
Beginning this school year state law now requires all schools to drill for an earthquake and tsunami scenario also known as stop, cover and hold on drills.
PCEMA and state agencies are amping up their preparation and activities for the 2022 Cascadia Rising Drill. that entails the cooperation of dozens of agencies to prepare for a CSZ event. Agencies alike are also pushing for residents to begin practicing for evacuations including having an escape route to higher ground planned and detailed that can be traveled on foot.
It is recommended that residents have supplies to sustain themselves for up to two weeks, because it’s expected it may be that long before resources can reach hard-hit areas of the county.
A large portion of the response is expected to focus on the Peninsula, where the most devastation is expected to occur. Resources are expected to come mostly from Eastern Washington, such as Fairchild Airforce Base, where the National Guard will launch air assets responding to the coastline.
“So many people think ‘I’m going to bend over and kiss everything goodbye,”’ McDougall said.
“The fact if 15% of your population died that still means 85% of your population is going to survive. Those who don’t prepare will survive but they then may wish they were dead because of the aftermath and having nothing to sustain themselves with afterward. This is why we push the preparedness message.”
Impact a bit more than anticipated
According to the DNR simulation model and McDougall, the largest impact from a tsunami to north Pacific County will be steadily, rapidly rising water that could impact most of South Bend, the Riverdale area of Raymond, and most-of downtown Raymond. Residents could see several feet of water in each area with residents having to seek refuge in the second or third story buildings or nearby hillsides.
“By the time the water comes that far up the river a lot of the energy will have dissipated,” McDougall said. “But we are still going to have water pushing into the area around the schools in South Bend. When they talk about 11 feet that’s right at the water’s edge and will also be tide dependent, There is potential in that L1 scenario that we could see more water in Raymond and South Bend than we originally thought.”
The water inundation to Raymond and South Bend will likely have residents stuck where they take refuge for quite some time McDougall points out. The water is expected, under favorable conditions, to slowly flow outwards into Willapa Bay and the Pacific Ocean which may take up to 48 hours. The bright side for the rising water for north county residents is that it isn’t expected to push much debris and the hazards inland.