After rumbling all spring, Mount St. Helens finally erupted at 8:32 on Sunday morning, May 18, 1980. When President Jimmy Carter flew over the area a few days later, he called the destruction “formidable.” What followed—the response and the ecosystem's recovery—also proved impressive.

The earthquake that signaled the start was quick. Not everyone nearby even felt it. But after five or six seconds, the initial small ash plume grew so large that observers could no longer see the mountain.

Firsthand observations describe a Northwest morning like no other, according to a comprehensive report released by U.S. Geological Survey in 1981. One party that was 14 miles away, watched the cloud “rolling over everything like a track on a caterpillar tractor.” Another observer compared the ash cloud to a “big black inky waterfall” and boiling oil, as he sped 100 miles per hour, outracing it.

That Sunday morning, Jim Scymanky and three other loggers were cutting timber when over the whirring chainsaws, he heard a “horrible crashing, crunching, grinding sound.” Then darkness came, followed by intense heat. Gasping for breath, the men’s mouths and throats burned. Scymanky had been knocked down; when he came to, he felt a “searing, painful heat.” Burns covered almost half his body. None of his companions had survived.

At a campsite 13 miles away, wind preceded the ash by 10 to 15 seconds and blew a woman’s braided hair horizontally. When the cloud arrived, the campers heard their hair “sizzle.”

The sky ahead of the wall of ash was green-tinged, with cedar trees and limbs hanging in the air. Thirty miles away, on a ridge near Mount Adams, a witness saw 100 branches dropping, some of them more than a foot long and nearly an inch thick, singed by the heat. Where trees still stood, pitch boiled out of them.

Amid the sky’s ashy chaos, lightning struck and ignited fires. A pilot south of the mountain saw strange lightning, like a ball, “streaking toward the ground, connected neither with the cloud nor with the ground.” At the other end of the elemental spectrum, ice, then mud balls, dropped onto fleeing people and cars.

The eruption melted snow and glaciers to produce 47 billion gallons of water mixing with 1.4 billion cubic yards of ash and rocks in huge mudflows. On the South Fork Toutle River, the stream turned into a “mass of water, mud, and trees.” A railroad trestle broke loose and caused a huge logjam. Wading in the muck was like moving through “warm concrete,” according to one witness. Mud and logs swept along a car before the passengers finally escaped, jumping log to log and wading through mud before reaching safety.

President Carter visited within days to observe the devastation from above. “Somebody said it looks like a moonscape, but the moon looks like a golf course compared to what’s up there,” Carter told the press.

Carter would have seen some of the damage, which included the North Fork Toutle River buried more than a dozen miles, lakebeds raised by almost 200 feet, nearly 5 billion board feet of timber downed, more than 20 bridges washed away and property damage of more than $1 billion. Almost 60 people died.

Although Carter emphasized devastation, the power of nature and what might come next also captured his attention. He told reporters that scientists and tourists would visit the landscape once it was made safe.

Carter was right. What he didn’t yet know is how much they would be surprised.

In June, three federal scientists helicoptered into the blast zone, steam still rising from the crater. After landing, Jerry Franklin, an ecologist with the United States Forest Service, climbed out. As writer Eric Wagner later described it, a flash of green caught Franklin’s eye. Already, fireweed was reclaiming its spot in the ecosystem. Franklin and his colleagues had expected life to take much longer to return. Mount St. Helens repeatedly humbled scientists whose predictions regularly underestimated what nature would do.

In 1982, Congress established the Mount St. Helens National Volcanic Monument to protect resources and allow “geologic forces and ecological succession to continue substantially unimpeded,” allowing scientists to study a landscape’s evolution in an unprecedented way.

Three decades later the once-gray landscape had greened up.

While the Forest Service stepped back, private timber interests stepped up.

The Weyerhaeuser Company owned 68,000 acres affected by the eruption. It responded with economic interests, salvaging as much downed timber as possible. According to the company, it employed more than 1,000 people, removed up to 600 truckloads of logs daily, worked for almost two years and rescued enough timber for 85,000 homes.

Next, the company planted seedlings, 18 million of them across some 45,000 acres, to start its next commercial forest. The company’s chief forester at its St. Helens tree farm, Dick Ford, told the The New York Times, “We had no idea if anything would even grow there because there was simply no precedent for something like this.” But it worked. Another Weyerhaeuser forester boasted, “We have done a much better job than nature.” By 2009, trees had reportedly reached 70 feet.

Having two types of forest in close proximity invited comparison.

For some of the local population, the recovering Weyerhaeuser Forest seemed promising and more important than studying ecological succession. During a debate about managing the national monument, one local resident voiced her frustration: “You don’t need 20,000 acres to see how vegetation comes back.” To her and others, scientific research and monitoring did not count as the highest use of the land and did not justify such restrictive classification.

Environmental scientists, however, learned much from studying how biological life returned. They found greater biodiversity where nature was left to grow at its own pace. What ecologists saw in the eruption’s aftermath helped them rethink logging practices, too. Clearcutting sweeps the land clean, but Franklin noted in a 2010 feature in BioScience that “if we’re interested in things like biological diversity and other kinds of ecosystem processes besides timber production, maybe we’d better rethink our concepts.”

President Carter had grasped this early on, noting in May 1980, “My guess is that over a period of time the Mount St. Helens explosion will be one of intense interest to geologists and volcanologists and others from all over the world, and it'll be a scientific curiosity in the finest sense of that word.”

Beyond geology, the mountain would reveal lessons about nature's resilience for decades to come.