MOUNT ST. HELENS — Col. Terry Connell was at his downtown Portland church one Sunday in 1980 when Mount St. Helens erupted.
“You could see all the smoke and the ash coming out of the mountain,” said Connell, who was then Portland District Commander for the U.S. Army Corps of Engineers. “The skies were overcast that day, but you could still see the cloud.”
It had been obvious for weeks the mountain was going to blow. The agency — in charge of waterways and major infrastructure like dams — however, was told staff wouldn’t encounter problems because the mountain was going to explode straight up, the 91-year-old Connell recalled.
He was speaking Wednesday at an event on the mountain meant to celebrate those Corps members who responded to the eruption 45 years earlier.
It soon became clear to Connell while sitting in an 8 a.m. meeting the morning after the eruption, Monday, May 19, especially as the then-director of navigation for the district spoke, that the major task before the Corps was to ensure America’s rivers don't flood and remain navigable for ships.
Director Adam Heineman was explaining in the meeting that six hours earlier, he had received a call from the U.S. Coast Guard, saying a ship was stuck in the middle of the Columbia River’s channel.
“Adam replied, ‘They're always claiming to be stuck in the middle of the channel,’” Connell said. But this time, it was true.
“The channel, at the time, was authorized to a depth of about 32 feet, but it turned out the river was only 12 feet deep, and the ship, in fact, was stuck right smack in the middle of the channel.”
The mission
When the mountain erupted, about 1,300 feet of its summit and a large part of its northern face collapsed. The debris then combined with melted ice and snow to become the world’s largest landslide, according to the U.S. Geological Survey.
In addition to filling much of the upper North Fork Toutle River Valley, the landslide sent about 300 million cubic yards of muck down the Toutle River, through the Cowlitz and into the Columbia, Connell said. Only 50 million cubic yards of that made it to the ocean.
Before the eruption, Connell said the Corps had been dredging about 10 million cubic yards at the mouth of the Columbia every year, as well as about 10 million yards from the river’s shipping channel.
Then, in an instant, it had about 250 million cubic yards to deal with, Connell said.
Restoring navigation — the heart of Southwest Washington’s economy — “was the single most, perhaps, important consideration for the nation and for the Corps of Engineers,” Connell said.
To do that, the Corps took a two-pronged approach. The first was heavy and near-immediate dredging. The second was stopping the practically unending flow of sediment at its source.
Sitting on the physical embodiment of the second prong on Wednesday, Connell gestured to former Corps’ staffers Rick Goodell and Steve Stockton: “They made it all happen. I just came and signed the checks,” he laughed.
Building long-term solutions
“It was two or three days after the eruption, and I was asked to go on a kind of a recon of the consequences,” Stockton said Wednesday. “And so we flew up the North Fork of the Toutle River Valley, looking at the different areas.”
At the time, he was a working-level civil engineer in the Portland District, and he’s still not sure why exactly he was chosen to be on the helicopter ride — but he followed orders.
Days later President Jimmy Carter would take a similar flight and famously remark, “I’ve never seen or heard of anything like this before. Somebody said it looked like a moonscape. But the moon looks like a golf course compared to what’s up there.”
Stockton’s first task was working with colleagues in the district's hydrology branch to assess the damage and predict what the continuing sediment flow would be. He and his colleagues’ research and designs led the Corps to quickly construct a giant levy across the valley floor along with a spillway for the river to flow through.
“Basically, you've got a barrier that slows the water down, and when the water slows down, it drops all the sediment out,” he said.
The dam reduced the flow of sediment, which had clogged the shipping channels, caused costly problems in towns along the Cowlitz River and increased flood risk along the Cowlitz and Columbia rivers.
Next, the true task began: addressing the problem long term.
In the 10 years following the eruption, the Corps approached the program from a variety of angles, culminating in the construction of the giant earth and concrete dam on which Stockton, Connell and others stood Wednesday. The dam is known by the functional name, “Sediment Retention Structure.”
Also during that decade, Stockton rose through the ranks of the agency, boosted by his successes with the Mount St. Helens response. By the time the final retention structure was completed in 1989, he had become the Portland District’s chief of engineering.
After that, he went to Washington, D.C., rising to become the agency’s national director of civil works. That role oversees the Corps’ multibillion-dollar civil works budget which enables millions of jobs and $1.47 trillion in goods to be transported each year.
Two feats
Although the region-shaping event has mostly faded from the spotlight these days, the scale of the feat the Corps pulled off has only just started to come into focus.
On the immediate side, what the agency accomplished on the shipping channel saved jobs and gave the region a much-needed win.
“The Corps’ dredges were brought immediately on the scene. We had them in operation in the Columbia River in that first week,” Connell said.
Within three weeks of the eruption, the Corps had more than doubled the channel’s depth to 25 feet. That allowed limited commercial shipping to restart. It also allowed the U.S. Navy to get some ships into Portland for the 1980 Rose Festival.
And within 100 days, the Corps had restored full commercial navigation in the river, Connell said. (Today, the channel allows about $31 billion in goods to be transported each year.)
Meanwhile, the 184-foot tall sediment retention structure has stood the test of time, still spanning the nearly 2,000-foot-wide valley.
As rains have slowly eroded some of the roughly 1 million Olympic swimming pools' worth of debris deposited around the valley, millions of cubic yards of sediment has made it to the dam. That’s raised the miles-long valley floor by about 100 feet, Corps spokesperson Kerry Solan.
New solutions amid political uncertainty
While the dam was initially expected to last until 2035, it has been a victim of its own success, largely filling up by 2012 from heavier-than-anticipated sediment flows and storms, a USGS report found.
That led it to be raised in 2013, increasing its effectiveness. Since then, however, it again has filled up and switched from catching about 80% of passing sediment to allowing 80% to pass, Corps spokesperson Jeffrey Henon said earlier this year.
That has led to costly problems for downstream cities like Castle Rock, Kelso and Longview. While work to refurbish the structure again was approved last year, it had been delayed, Castle Rock Public Works Director David Vorse said earlier this year.
Along with other federal agencies, the Corps recently has been thrown into turmoil both nationally and locally as the Trump administration has quickly trimmed jobs and funding.
Those actions could have compounded years of delays and uncertainty about when the next dam raise would happen. But it didn’t.
“The District received $59.2 million for SRS (the Sediment Retention Structure) in the (2025 fiscal year budget) which funds the 10-foot crest raise to completion,” Corps spokesperson John Morgan said by email Thursday, adding work is set to start summer of 2026.
Eventually, however, the current structure will be buried by sediment, forcing the agency to again find a way to address the problems of Mount St. Helens’ sediment — an issue the Corps acknowledges is in its infancy.
Asked if the agency could accomplish the same feat its engineers did in the aftermath of the 1980 eruption in today’s environment, both Connell and Stockton were matter of fact.
“Absolutely yes. But the Corps, then, within the various districts and divisions, would have to do a prioritization of what is crucial and critical for public requirements and what might be pared back a little bit in order to provide for what is really crucial,” he said. “Can that be done? If it has to be done, it has to be done.”
And with the agency having been hit by roughly $1.5 billion in cuts to civil works funding this year and the upper North Fork Toutle River valley still holding about 1 billion cubic yards of sediment waiting to be washed downstream — it will have to be done.
