Soon after the eruption, depressions filled with rainwater and created some 120 new ponds. Willows, red alders, grasses and reeds grow around the edges of the water. In this place the areas between the ponds are still quite rocky, gravelly and gray. The renewal of life on Mount St. Helens. But in and around the ponds there are Pacific treefrogs, Western toads, red-legged frogs, Northwest salamanders and a ton of bugs scooting all around. Amphibian egg masses cling to underwater plants. The place is thriving with life. Sit on a cold gray rock, boots in the gravel, and just look down. Decomposed leaves turn to dirt. Bugs and spiders crawl everywhere. A flower reaches for the sun, ready to bloom. A treefrog sits in the water nearby. This is joy. Why then, how then, do we consider the roaring eruption as some sort of destruction? The mountain exhaled and brought all this here. The field of disturbance ecology gained a state of the art laboratory after the eruption. The new lab was huge, 230 square miles, and divided into several sections: areas where some life survived, areas swept clean of life and some areas so radically changed that altogether new habitats were created. During the last 20 years scientists have watched the land evolve and new ecosystems develop in the ruins. "The idea that large disturbances, albeit infrequent, have a long lasting impact on the ecology of affected areas was brought to a point by Mount St. Helens and has been further refined in the 20 years since," says Peter Frenzen, monument scientist at Mount St. Helens National Volcanic Monument. The mountain’s close proximity to research facilities provided an unprecedented opportunity for scientists. They could return repeatedly through time to watch as the post-eruption changes unfolded. And they have done just that. The southern Washington volcano awoke in March 1980. All through the spring, thin columns of steam and ash rose from the summit. Magma pushed from below, creating a quickly growing bump on the mountain’s northern side. On May 18, after a four day calm, a sudden earthquake at 8:32 A.M. dislodged the bulging flank of the mountain and set loose a giant slide of rock, magma and chunks of glacier. The avalanche tumbled into the Spirit Lake Basin, up and over Johnston Ridge to the north and westward down the North Fork Toutle River. After the slide, the pressure below the mountain could no longer be contained, and a violent eruption followed. A lateral blast swept northward over ridges, quickly followed by a second outburst that spewed hot gas, pumice and ash upward as high as 15 miles. The rubble rained down for hours, landed on top of the jumbled debris north of the mountain and created a lifeless plain. The eruption left the mountain with a gaping breach on its northern side. The pieces of the old peak settled in the valleys below, forming a jumble of large individual mounds, known as hummocks. As the blast traveled over the ground from the crater it lost the energy to move mountains but not to destroy. Trees and surface dwelling animals were vaporized A spider emerges from an animal skeleton. by the blast. Farther from the epicenter, the eruption’s power was slightly more diminished. Old growth trees were snapped and blown over. Farther away still, trees were left standing scorched and limbs were torn away. In the summer of 1981 a helicopter delivered a group of geologists to the still smoldering crater of Mount St. Helens. The eruption had blown 1,300 feet off the mountain’s summit. They stepped out of the helicopter into what used to be the heart of the mountain. Rocks falling from the steep walls echoed in the crater as the drone of the helicopter faded. Sulfur fumes leaked from fissures scattered in the dusty void. The wind blasted tiny particles of razor sharp ash. A full year after the eruption the crater still seemed barren. Then someone pointed toward unexpected movement in the gray dust. Incredibly, a small mouse scurried among the stones. They couldn’t figure out how it got into the crater. Perhaps a hawk dropped the rodent from its talons, and somehow it survived the fall. "We all felt so sorry for this little mouse," says Kathy Cashman, one of the scientists in the crater that day. "It was warm up there, but there wasn’t much in the way of food." The visitors left crumbs for the mouse but doubted it could survive once their charity ran out. Life had already immigrated to the hostile environment of the volcano’s mouth, and it’s unlikely the mouse dropped from the sky. Charlie Crisafulli, an ecologist who has worked on the mountain since 1980, thinks it probably just ran up there. Mount St. Helens "enabled us to see how far some species can go to colonize available Scientist Charlie Crisafulli releases a Northwest Salamander caught in a funnel trap. habitat," he says. Not only did some species travel from farther away than expected, but they also arrived sooner than expected. Some species returned more vigorously than anyone imagined. As researchers surveyed the aftermath of the eruption, they learned how, just by chance, small islands of life survived the blast. "At the time of the eruption," says Frenzen, "I don’t think anybody fully appreciated how much surviving plant life there was." Today researchers understand that the destruction wasn’t as complete as they first imagined. Not only did some plants survive but so did insects, spiders, amphibians and mammals. Had the eruption happened only a few months later, it would have been much more devastating. The timing of the blast, during a spring with high snowfall that provided a protective blanket, illustrates a recurring theme of disturbance ecology — the role of chance. Cashman is a volcanologist at the University of Oregon who has been studying the mountain since just after the eruption. She flew over the ridges to the north of the volcano and saw how the blast scoured the southern slopes but spared some of the small evergreens sheltered by deep snow on the leeward northern sides. After the eruption those protected areas harbored life that spread into the harder hit areas, speeding the pace of renewal. "I am amazed at how fast it’s been," she says. When the mountain blew, Cashman was at sea off the East Coast of the U.S. working on geophysical research. After returning to the mainland she lobbied for a job with the Cascade Volcano Observatory in Vancouver, Washington. The research station needed someone with her expertise, but they could only offer her a position educating the public and the media. She took the job and began doing her own research during the summers on the crater’s growing lava dome. "The thing that is most impressive — and this is a lesson I learned from Mount St. Helens — is that the eruption is only the beginning of a number of significant changes," says Cashman. In her years on the mountain, she has noticed great changes in the crater. In 1981 it contained a little lava dome growing out of the crater floor. Now, after years of constant rock fall, the floor is filled with boulders and gravel. This shifting and settling not only occurs in the crater but also around the entire area affected by the eruption. For many long time residents of the Northwest, Mount St. Helens conjures up images of the catastrophic blast, but scientists have been focusing on the aftermath. Before the eruption, ecologists knew that areas are often altered by major upheaval. The eruption put things in perspective. Today, largely because of work done on the mountain, scientists know more about relationships between the surviving and colonizing plants and animals within a dynamic landscape. Frenzen was a student at the University of Washington 20 years ago. He was part of a group studying the changes in vegetation caught in the path of a mudflow on Mount Rainier. This early contact with how ecosystems evolve and how they react to disturbance set him up for the events of May 1980. When Mount St. Helens erupted he knew he wanted to continue his studies there. The eruption occurred early in his career, and he has been studying the mountain ever since. Frenzen’s adviser in graduate school was Jerry Franklin, then at Oregon State University. Franklin and his students developed ideas on Mount St. Helens about how the legacy of surviving plants, and of decaying organic matter, affects the re-growth of a forest. The localized effects of a log on the ground or in a stream can be profound. Logs and stumps provide water retention and shade for young plants, allowing for a more diverse and rapid renewal. Franklin considers "the ubiquitous and varied nature of biological legacies and their importance in the recovery process" to be one of the most important results of 20 years of research on the mountain. "Almost all ecological theory about succession, as it has been taught in textbooks, is misdirected or at least totally unbalanced," says Franklin. While many scientists understand the value of research done on the mountain, others are slow to change their views. "Scientists are like everyone else — they hate like hell to give up their pet beliefs about things."