On a sunny Saturday afternoon in June, John Anderson, a 43-year-old sawmill worker, sits in front of his pretty green-trimmed house in a family-friendly subdivision in Orting, Washington, not far from Seattle. He gazes contentedly down the street, scratching his neat goatee and watching the neighborhood kids shoot hoops in a driveway. It's an ordinary day in suburban America, but here in Orting, behind every house, mostly ignored, is 14,410-foot-high, snowcapped Mount Rainier. This is one of the continent's most spectacular sights: a mountain that seems to loom and then recede, sometimes crisply focused and near enough to touch, at other times shifting into the fog, vanishing, then reappearing. "When we get a full moon and it comes up over the mountain, it's really something," says Anderson, leading a visitor into the backyard for a better view.
Anderson takes Rainier for granted. The mountain views came with the house, which cost $120,000 three years ago. In most places, such views would only add to the value of real estate over time, but Anderson's house hasn't appreciated a dime since he bought it. That's because Mount Rainier, the highest point in the Cascades, is not just lovely scenery. It's the most dangerous volcano in the United States. When it erupts— and it will— blistering avalanches of incandescent rock, lava, and ash will sweep down the volcano. Worse, unimaginably large flows of mud hundreds of feet deep, called lahars, filled with melted ice, boulders, and whole forests of uprooted trees, will pour down adjacent river valleys at upward of 25 miles an hour. Like concrete cascading down the chute of a cement truck, the lahars will entomb everything in their path. And that path runs right over Anderson's house.
Rainier is one of a score of volcanoes in the Cascades, from Northern California to British Columbia. Seven Cascades volcanoes have erupted in the past 200 years. All are smoking guns. "They say it's not if, it's when," Anderson says. The only question is how many people will die. As the U.S. population has doubled since 1943, whole towns have been built closer and closer to many of the 68 potentially active volcanoes that bubble away in Western states, Alaska, and Hawaii. Millions of people live in Seattle and Tacoma. Between the two cities and Mount Rainier, at least 100,000 people live on the solidified mudflows of previous eruptions. Orting, population 3,600, is one of the towns built on ground that is itself clear warning of danger. Known for logging and growing hops, Orting has a main street with a Timber Tavern and Frontier Bank on one side, a tree-shaded plaza on the other, and a postcard-perfect view of Mount Rainier at the foot. Inexpensive real estate has encouraged construction of at least three new housing developments like the one Anderson lives in. "And there's a new elementary school going up," he says.
To a layperson's eye, Mount Rainier looks unchanged from the way it appeared two centuries ago when a member of Captain George Vancouver's exploratory crew first sketched it— serene, stately, a symbol of permanence. Here, looks are deceiving. Rainier sits along the boundary of tectonic plates forming Earth's crust. Off the coast of Seattle in the Pacific Northwest, a heavy chunk of seafloor called the Juan de Fuca plate has been ramming itself under the lighter North American plate at the rate of an inch and a half a year, about a third as fast as hair grows. Squeezed and heated, the rock melts into magma, blobs of which rise toward the surface into chambers where it becomes trapped, cooking and rolling like boiling oatmeal. When the pressure becomes too great, it bursts free, throwing out lava, gas, steam, ash, and hot rocks. Rainier is a series of successive lava flows broken up by centuries of ice, water, percolating volcanic gases, and the mountain's own internal heat. When scientists look inside Rainier, they find some of its rock crumbly and weak. The mountain is dangerously unstable, a tall, steep heap of loose rocks held together by the force of gravity and a cubic mile of glacier ice that could be melted or shaken loose.
