PORTLAND, Ore. – As a helicopter touches down in a parking lot next to the top of Cougar Dam, a massive, 519-foot-high rockfill structure in Oregon’s McKenzie River Valley, a small team of engineers in bright red shirts printed with “Emergency Operations” stands by, waiting to climb aboard.
The pilot gets out to help the engineers load up their gear—backpacks and hard hats, one of them strapped with a head lamp—and starts talking to Col. Mike Helton, commander of the Portland District, U.S. Army Corps of Engineers.
They look out over the dam and the valley below. Pinpointing a good landing spot, the pilot admits, was a bit tricky. The parking lot seemed ideal. But then, hands on his hips, the pilot says something that brings the grim reality of what this team is training for into sharp focus: “If the earthquake hits, this parking lot might not even be here.”
Of course, for the portended earthquake many have come to know as “The Big One,” it’s less a matter of if than when.
The Pacific Northwest is due for a severe earthquake—potentially as large as magnitude 9.2—from the Cascadia Subduction Zone, a 700-mile “megathrust” fault line off the Pacific coast, stretching from northern California into British Columbia.
The last time an earthquake occurred in this fault was Jan. 26, 1700. It measured an estimated magnitude 9.0. According to the Oregon Office of Emergency Management, the quake caused the coastline to drop several feet and triggered a large tsunami that crashed into the land.
Today, seismologists predict the Pacific Northwest has a 40 percent chance of experiencing another similarly large earthquake during the next 50 years.
The Corps of Engineers is taking those odds very seriously.
The Corps’ Northwestern Division, which encompasses five separate districts (Portland, Seattle, Walla Walla, Omaha, and Kansas City), led a regional exercise June 14-16 to prepare its teams of emergency planners, operators, and engineers for the possibility of such a disaster.
The exercise scenario was dire. A rupture along the fault line on the coast of Oregon, near the city of Florence, caused a catastrophic magnitude 9.0 quake, resulting in a tsunami up to 80 feet high. Thousands of people dead. More than a million buildings damaged. Widespread power outages. A total loss of communications for the Corps’ Portland and Seattle districts, with 70 percent of the two districts’ employees impacted.
It's a situation Portland District Catastrophic Disaster Response Program Manager Mark McKay sums up with a single word: devolution.
It means the damage is bad enough to essentially take the Portland and Seattle districts out temporarily. So the Corps’ Walla Walla District, which lies far enough east to remain unaffected by the quake, takes over command and control for its sister entities.
Portland and Seattle set up fully functional command posts outside of the earthquake’s impact zone and spent most of the three days taking accountability for their teams and infrastructure.
“Real accountability would take a long, long time because people are going to take care of their families,” said McKay. “They may not check in for a long time.”
The major lift for the two districts? Checking on the nearly 30 dams they operate and maintain.
For the exercise, Portland District dispatched local damage assessment teams—small groups of engineers who live near the district’s dams—to perform safety inspections on the structures. According to McKay, these teams are brand new. The district just implemented them within the past year.
The district also put several battery-powered, briefcase-size satellite units into operation throughout its 13-dam Willamette Valley System—in this scenario, the hardest hit area of Corps locations—which the teams used to relay data and information on to an emergency operations center at Walla Walla District.
Walla Walla sent in a five-person team of engineers by helicopter to inspect Portland District’s Cougar and Blue River dams—remotely operated, isolated structures in Oregon’s McKenzie River Valley, east of Eugene, that Portland District teams might not be able to make it to.
While any needed repairs to the structures would be a long way off, immediate assessments of the dams’ conditions would allow the Portland District to prioritize the management of the dams and reservoirs toward the best outcome for communities living downstream.
Erik Petersen, the district’s Willamette Valley operations project manager, uses the current situation across the valley, brought on by late-season rainfall in May and June, as an example of how difficult those decisions could be.
Right now, Corps reservoirs across the valley are the fullest they’ve been in the past few years. A major seismic event, Petersen says, would complicate the district’s ability to keep rivers from flooding downstream. Dams in need of evacuating the water stored behind them would be opened for releases, while others would remain closed. Easier said than done, of course.
“If and when Cascadia happens, the whole West Coast is going to experience upset conditions,” Petersen said. “Things are going to be upside down. And we don’t want to make the situation worse by not doing everything we can do to protect the populations at risk downstream of our facilities.
“We want to do all we can do to protect people. And that’s what this is about.”
The somewhat good news is that dams have historically performed extremely well during seismic events. Only one concrete dam in modern history has ever failed as the result of a seismic event: Shih-Kang Dam in Taiwan. According to Northwestern Division Dam Safety Program Manager Ross Hiner, even for earthen embankment dams, which could be more vulnerable to an earthquake, failure of the structure is rare and remains unlikely.
Nevertheless, in recent years, the Portland District has launched seismic studies and risk assessments at each one of its dams to better understand the structures’ expected performance in the event of a major earthquake. Findings from those studies will determine long-term measures the district may need to implement to improve the seismic safety of its dams.
The district has also trained for a Cascadia earthquake in the past. It participated in a national-level exercise in 2016 and has conducted intermittent exercises in the years since. According to McKay, the district stands up its emergency operations command post twice a year.
“You’ve got to practice,” said McKay. “It’s the Super Bowl of disasters for emergencies, and you’ve got to have a team, you’ve got to practice, you’ve got to have some scrimmages, you’ve got to play some games, and you’ve got to go to the playoffs before you get to the Super Bowl.”
McKay added that the COVID-19 pandemic gave the district some unexpected preparation because it forced the organization to figure out how to work effectively in a dispersed environment.
“Once you get internet, people can work from anywhere,” said McKay. “So we got to practice and not even really realize it.”
Of course, McKay admits, some mistakes were made during the district’s recent exercise. But that, he added, is why agencies train.
The drill alerted the Corps to updates it needs to make to its operations plans and documents, phone rosters, emergency accountability reporting tool, and even the need to have amenities like food and water on site at its dams for inspection teams.
Ask Petersen, though, and he’ll tell you the Corps is on the right track, mistakes and all.
“I’m really proud of the team that we have in place,” Petersen said. “They’re extremely committed. They demonstrate that every day. And in the event that they experience Cascadia, I know we’re in the best hands that we could be in.”