A Landscape Changed In An Instant Keeps Evolving, 40 Years After Mount St. Helens Blew

May 17, 2020

NOTE: This story is a collaboration between the public media Northwest News Network, Spokane Public Radio, Northwest Public Broadcasting and the Spokesman-Review.

The black-and-white images of the 16-mile high stanchion of ash give a false impression.

The photos of Mount St. Helens’ eruption taken on May 18, 1980, suggest a cataclysm that remains in the past, safely ensconced in history and available for warm recollection of when the world exploded and we survived.

But that’s wrong.

Look no further than the abiding pocket gopher – or the chocked Spirit Lake and road builders of the Pumice Plain – to know the continuing effects of the eruption 40 years later.

At the time, the gophers survived the devastation by hiding in their burrows deep under the snow and dirt. Just a few days after the eruption, their mounds could be seen on the mountain by researchers flying overhead in helicopters. This key species helped others return, and still lives up there, high above the tree line.

Spirit Lake was and remains clogged with the trees blown down by the eruption decades ago. A tunnel built after the eruption to help drain the lake is now in need of repair. Government engineers have proposed building a new tunnel and corresponding road through the Pumice Plain, “one of the most closely studied patches of land in the world,” according to a recent article in High Country News. Volcano scientists and conservationists are fighting the proposal.

In other words, Mount St. Helens’ story didn’t end when the ash settled and the landslides ground to a halt. It’s still going on today.

“The geology story played out pretty quickly,” said Fred Swanson, an earth scientist who has studied the mountain before and after the eruption. “The hydrology and erosion and sedimentation issues persist to this day.”

Eric Wagner is a science writer in Seattle who recently published a book about the ecology of Mount St. Helens called “After the Blast” and wrote the High Country News article. In a sense, he said, the eruption never really stopped.

“There’s never, ever a real sense of stability there,” Wagner said in an interview. “That’s the price of living on Earth.”

‘And then it happened’

Seth Moran was a 13-year-old “volcano nerd” in Massachusetts when Mount St. Helens erupted and seized the world’s attention. 

He had recently read a book about volcanoes around the world. The last chapter focused on the Cascades – the string of mountains stretching from British Columbia to California that are part of the Pacific Ocean’s volcanic Ring of Fire. The chapter was titled, “Sleeping Giants.”

“It was fascinating,” Moran said. “There was never any talk of something happening, and then it happened. That really blew my mind.”

The eruption sealed his fate, and Moran got a geology degree in college, before attaining a graduate degree in seismology and a doctorate in geophysics from the University of Washington.

Downtown Spokane, Washington, was covered in ash from the eruption of Mount St. Helens.
Credit Spokesman-Review Archives

Now, Moran is “scientist-in-charge” at the Cascades Volcano Observatory, which was established in Vancouver, Washington, by the U.S. Geological Survey after the Mount St. Helens eruption.

The observatory keeps an eye on all the volcanoes of the West Coast. Baker, Glacier Peak, Rainier, Hood, Shasta and Lassen have all erupted in the last 200 years. During the past 4,000 years, eruptions of the 11 active volcanoes in the range have come about twice a century on average, according to the USGS.

The most active of the group is St. Helens. In fact, there were 20 more eruptions following the big one in 1980 until 1986, leaving behind a new lava dome. Huge clouds of ash burped out of the mountain a few times between 1989 and 1991. And magma reached its surface in 2004, inaugurating another four years of active vulcanism and mountain building.

“The St. Helens of today is, at the surface, dormant. Not really erupting at all,” Moran said. “There’s plenty of activity going on beneath the surface.”

Fifty miles below the mountain, the Earth moves. Though far underground, it’s here where the ocean meets the land. More specifically, where the Juan de Fuca oceanic plate meets the North American continental plate, creating what scientists call a subduction zone. In this case, the Juan de Fuca plate is being jammed underneath the continental plate, creating unimaginable forces and pressure.

Sometimes, what happens below comes to the surface, and molten rock flows. But much of the time, the underground work of tectonic plates is witnessed only by scientists with technical equipment. Like today, as scientists monitor earthquakes happening five miles underfoot.

“There’s a lot of similarity to the earthquakes we’re seeing today to those that were going on between the two eruptions,” Moran said, referring to the 1980 and 2004 eruptions. “We infer there’s once again a recharge going on. It’s not telling us the volcano is going to erupt tomorrow or next week or next month, but it is a sign that the volcano is still alive and well and that we might expect to see an eruption in a time frame of years to decades from now.”

When it does erupt again – because it will erupt again – Moran says it won’t be like 1980.

“That was cataclysmic and unprecedented in a number of ways,” he said. 

Mount St. Helens, clearly, is an explosive volcano. But the 1980 eruption was different because of the accompanying landslide, which instantaneously took the pressure off the intruding magma below.

“It was exactly like taking the lid off of a Coke bottle that you’ve shaken up. It came out in a much more violent way than it otherwise would have,” Moran said. “Today, the volcano is missing a chunk of itself, and it’s missing part of the cap, or the cork, that would be available to hold in the pressure.”

‘Vancouver! Vancouver! This is it!’

On the morning of May 18, 1980, a 30-year-old volcanologist named David Johnston was staring at the north slope of Mount St. Helens. 

Two months earlier, the volcano had signaled its return to life after 123 years of hibernation. Shallow earthquakes were followed by steam explosions and hiccups of ash. The USGS had sent a team to monitor the activity. Johnston was a principal scientist heading up the volcanic gas studies, and was posted at an observation point 6 miles north of the mountain. 

The sky was clear that day, and the sun rose at 5:30 a.m. So did Johnston. Out of his camper, Johnston checked the growing bulge of St. Helens with geodetic equipment. The growth had slowed. It was only about two feet bigger than a day earlier. At 6:53 a.m., he radioed in his measurement to the USGS office in Vancouver, Washington.

Not two hours later, at 8:32 a.m., a 5.1-magnitude earthquake triggered a landslide on the mountain’s north face. The mountain began spewing steam and gas and, seconds later, it erupted from its north side. Not its peak, but the face Johnston was examining. A dense mass of super hot ash, lava and gas came screaming at Johnston at supersonic speeds. This was soon joined by violent mudflows roaring down the North Fork Toutle River Valley.

Though six miles away, Johnston had less than a minute to react. He grabbed his radio: “Vancouver! Vancouver! This is it!”

The Johnston Ridge Observatory on the north side of the current-day Mount St. Helens National Volcanic Monument is a popular tourist and interpretive spot now, marking the spot where volcano scientist David Johnston lost his life while observing the mountain on May 18, 1980.
Credit USGS / Public Domain

Seconds later, his signal went silent.

The eruption was heard hundreds of miles away. Ash rained on Spokane and as far as Nebraska. In its wake, $1 billion in damage was done, and 57 people died. Johnston was the first of them.

Ten days later, Fred Swanson was in a helicopter looking for Johnston’s camp. He was joined by Harry Glicken, another USGS volcanologist who had switched shifts with Johnston so he could talk with a professor about his ongoing graduate work. Also on board was Barry Voight, geologist and brother to Jon, the actor.

Johnston’s body was never found, but pieces of his camper and backpack were. Glicken, guilt-stricken over his colleague’s death, had three helicopter pilots fly him over the mountain in those first days. A decade later, Glicken was doing research on the active Mount Unzen in Japan. It erupted and he was killed, just like Johnston. The two are the only American volcanologists to be killed in volcanic eruptions.

“What we were trying to do on that first trip, in addition to Harry and Voight looking for the David Johnston camp, we were also trying to figure out the relative timing of the giant landslide and the blast,” Swanson said.

But they saw the beginning of what’s continuing to this day.

“There had been forests on that long slope down to Spirit Lake that had established after that eruption back around 1800,” Swanson said. “So it was big timber. It wasn’t old growth in the sense of being many centuries old, but it was approaching 200 years. A lot of the floating mat of logs that are now still on Spirit Lake and moving around with the winds, those were trees that were on the slope between the main body of the volcano down to the shores of Spirit Lake. They were shoved into the lake by the landslide.”

The landslide also hit the lake with such ferocity that a wave, hundreds of feet tall, swept bare the lake’s adjacent slopes.

“It’s totally mind boggling,” Swanson said. “I’m still breathless when I go in there all these years later.”

A place of wonder

Pumice Plain lies between the volcano’s crater and where Johnston camped.

Before the volcano, it held all those trees that are now floating in Spirit Lake, and it was home to countless creatures and plants that call a forest home. But the plain was “sterilized of life” by the eruption, according to the Mount St. Helens Institute

Since then, it’s become an example of what happens after a volcano, and “ecologists have scrutinized it, surveying birds, mammals and plants, and in general cataloging the return of life to this unique and fragile landscape,” according to Wagner in High Country News.

A debris avalanche obliterated forests and and left behind ponds of water surrounded by ash, as seen up close in this 1980 photo.
Credit U.S. Forest Service

Now, the landscape is under threat again. This time it’s not from a volcano.

After the 1980 eruption, Spirit Lake “was left a steaming black broth full of logs, dead animals, pumice and ash. Its surface area nearly doubled to about 2,200 acres, and its sole outlet, to the North Fork Toutle River, was buried under up to 600 feet of debris,” Wagner reported in High Country News.

With no outlet and nature’s continual recharge of rain and snow, Spirit Lake began to rise. If it spilled its banks, another mudflow could rage down the North Fork Toutle River Valley and threaten the people in Longview, Castle Rock and Toutle.

The U.S. Army Corps of Engineers found a solution in a 1.6-mile tunnel it built in 1985 below Johnston Ridge, named for the scientist who died in the eruption. For decades it worked, but the tunnel has been damaged by the area’s seismic grumblings, leading engineers to close it multiple times for maintenance. 

But the repairs are not enough. The U.S. Forest Service, which manages the Mount St. Helens National Volcanic Monument, has plans to build a second outlet for Spirit Lake. To do that, it needs to drill into the earth to assess the debris’ composition. And to do that, the agency has proposed building a 3-mile road through Pumice Plain to move drilling equipment to test sites.

The National Guard turned out to help across the region. These guardsmen worked on clearing ash from an elderly woman's house and yard in Ritzville, Washington. The elderly were hit particularly hard by the heavy loads of ash. Phil Schofield / Spokesman-Review
Credit Phil Schofield / Spokesman-Review

Scientists studying the mountain and conservationists have objected. In April, the Forest Service gave a green light to the road.

“The monument was created in 1982 as a place where geologic processes and ecological succession can continue substantially unimpeded. The ‘substantially unimpeded’ part is what everybody hangs their hat on,” Wagner said in an interview.

“It’s like a big national laboratory,” he said. “It’s a big natural experiment taking place on this vast scale. So you have this sense that the land is operating on its own. But the closer you look, you see how that really isn’t true.”

Wagner says the “ideals” of letting nature run its course don’t always fly with surrounding communities that don’t want their towns destroyed by a mudflow, or that would prefer hiking, fishing and camping on the mountain instead of keeping it pristine.

Wagner says no one wants Spirit Lake to overflow. But some see a better solution to building a road like, for instance, surveying drill sites by helicopter. But that would be expensive and logistically complex.

Regardless of what happens to Pumice Plain, Wagner points to it as a place of wonder, scientifically speaking.

It’s where prairie lupines took root after the eruption. The first seeds of the purple-blue wildflowers likely arrived with the wind, and each of these growing legumes “fixed” nitrogen in the soil and created a microhabitat that allowed other plant species to thrive. The plants trapped debris and lured insects, which ultimately died near them and decomposed, further enriching the soil.

Gophers, the early survivors, tunneled through the earth, mixing up this rich soil created by the lupine and creating more places for new plants to grow. One of those plants was Indian paintbrush, which attracted elk, whose hooves broke through the crust and mixed the soil with their droppings, which contained seeds and fungal spores, furthering biological diversity.

“Every organism that was there before the eruption is now back,” Wagner said. “Just in different abundances and different ways.”

The timescale of geology moves so slowly that it’s generally beyond human comprehension. A volcanic eruption is the exact opposite, when the forces of earth move destructively fast. But life on Earth perseveres through it all. Even on the side of a volcano.

“I was talking to a forest ecologist and he said, ‘You know, 140 years is within the lifespan of a tree,’ ” Wagner said. “A big Douglas fir can live several hundred years. To live and grow on the slopes of Mount St. Helens is to be subject to multiple eruptions over the course of a lifetime. There’s never really a sense of stability there. There’s always going to be flux and disturbance and change.”