Thirty years (and one day) ago, Mount St. Helens blew its top. Or rather, its side. After months of heightened seismic activity, a 5.1 magnitude earthquake caused the flank of the mountain to suddenly fall away. The landslide — the largest ever recorded — slammed into Spirit Lake at the foot of the volcano. A surging flow of mud, boulders and trees rampaged 13 miles down the North Fork of the Toutle River, a pyroclastic flow left miles buried in pumice over 100 feet deep, and the blast blew down 143 square miles of forest. (The following summer, 600 truckloads of timber were salvaged — every day.)
When the ash settled, Spirit Lake was clogged with debris, its surface 200 feet higher, and over 1,000 acres larger, than before. Only algae and bacteria survived in its water. But such a traumatic event made the lake, and the rest of the Mount St. Helen's blast zone, the perfect place for ecologists to study how a landscape recuperates.
Congress turned the region surrounding the mountain into a National Monument in 1982, stipulating that "geologic forces and ecologic succession (should) continue substantially unimpeded." Since then, we've learned immensely from Mount St. Helens, lessons about biodiversity and disturbance ecology that might prove useful elsewhere. To cite just a few examples, boreal toads may need large-scale disturbances to flourish, which could have implications for forest fire management; and lupine, one of the first plants to colonize ash and pumice, creating soil, could help remediate strip mines.
Many people fondly remember Mount St. Helens area as a vacation spot, especially Spirit Lake, which had camps and lodges along its edge. Recently, Puget Sound's KUOW caught up with some who remember the lake as an emerald and evergreen destination:
Billie Dunne: "Spirit Lake was so beautiful, you can't believe it. It was so gorgeous. And the mountain was right there and we'd go swimming [...]"
(Reporter Tom) Banse: "When the mountain erupted and changed that lake forever, do you remember thinking, aw, there went Spirit Lake?"
Billie Dunne: "I was sick, just sick about it, yes."
David Dunne: "I remember hearing that day that Spirit Lake was gone. That what they said, the news reports, said it appears from the helicopters that Spirit Lake is gone, because it was so covered with debris you could not see the lake anymore."
Mount St. Helens may be a shadow of its former self, but, not surprisingly, some are lobbying for increased access to its spectacular environs. There's been talk of building a seven-mile road from the Monument's visitor center to Spirit Lake, for example, as well as turning the Monument into a National Park. Scientists, of course, are wary of opening up more of the region, and lake, to increased traffic of any sort, for fear that it'll taint their long-term studies.
Spirit Lake, however, is not a pristine laboratory. Fifteen years ago, rainbow trout were dumped into the lake, and they've grown large and prosperous, to the chagrin of amphibians. And before that, in 1985, the Army Corps began to manage the lake, when it stabilized its surface level, for the sake of sediment and flood control. They drilled a long tunnel through a ridge to lake, creating an outlet.
Yet while Spirit Lake isn't quite "natural," allowing tourists vehicles to its edge might expose it to motor oil and gas runoff, air and noise pollution, and general wear and tear. We should find ways to encourage people to see the dramatic Mount St. Helens landscape, certainly. But we should also be careful not to spoil an environment that we're only just learning from, three decades after the explosion.