THUNDERING like stampeding horses, the gray slurry churned over Mario Steban's farm.From a hill lookout above angry flood waters, the young farmer recalled his family's narrow escape in September when a watery wall of sand and rock, torn from the slopes of Mt. Pinatubo by monsoon rains, surged across his four-acre farm. "We didn't even know the volcano existed. We didn't expect anything," said Mr. Steban who now works as a porter to support his wife and two children. "It's sad because I lost my livelihood and my house was buried, including 20 sacks of rice, which would have supported us for three months." Torrents of volcanic debris, known as lahar, are exacting a devastating toll in the desolate, ash-covered wasteland left by Pinatubo's eruption last summer. With the heavy monsoon rains beginning in September, the volcano's rampaging aftermath pushed the death toll this year to almost 700 people.
Decade-long threat The end is not yet in sight, say volcanic experts tracking Pinatubo and the lahar destruction spreading across Luzon island, the economic and political center of this island nation. More than 2 billion tons of volcanic ash blanket the slopes of Pinatubo, according to Raymundo Punongbayan, who heads the Philippine Institute of Volcanology and Seismology. Only about 10 percent of that has been dislodged, although scientists predict up to half of the debris could come cascading off the slopes in the next few years. "We're expecting heavy lahar flows over the next decade," says Kelvin Rodolfo, a specialist on lahar flows at the University of Illinois-Chicago who grew up near Pinatubo. Lahar is different and more deadly than a mud flow, experts say. Containing large concentrations of sand and pumice, lahar travels quickly, changes course rapidly, clogs up river beds, and overwhelms anything in its path. Lahar already impedes sections of the 10 river systems flowing off Pinatubo, triggering widespread flooding in the towns and farmlands below the mountain. Although the biggest human and economic toll has come in heavily populated communities on Pinatubo's eastern slope, the heaviest rains and greatest lahar threat are on the western side, north of United States Subic Bay Naval Station. Along some tributaries, the debris has backed up and dammed the water, raising fears of a sudden surge when the barrier breaks. Pila, a community of 6,000 people built around a profitable gold and copper mine, has been isolated for several weeks by a four-mile lake created by a one-mile-long lahar barrier. Food prices in the small hamlet have more than doubled. "What we are after is a source of living," says Edna Marzan, a school teacher whose classroom is buried. "We are having trouble getting our food." Since last summer, more than 500,000 Filipinos have sought refuge from the steaming lahar flows in overcrowded evacuation centers. Worst hit are the 16,000 Aetas, a dark-skinned tribal people who for centuries have lived on and worshipped Pinatubo. Most of the 300 people who have died in the camps are Aetas.
Little government aid In Pila, however, others are also suffering, residents say. On a desolate hillside above the lahar-created lake, 19-year-old Arnel Mia lays almost lifelessly, awaiting medical treatment. Relatives trying to bring her by boat, stretcher, and bus to the nearest town for help say she may not make it. "This government has so many problems and no money," says Bella Eclarino, a housewife who looked out at her nearly submerged house in Pila. "We have our hands full." Lahar's quicksand-like consistency renders heavy equipment useless in removing and directing the debris flows. Experts say the government will have to build dikes and diversion channels and install pipes to siphon off backed-up water. Tens of thousands of people will need to be resettled, irrigations systems and other infrastructure rebuilt, and farmland cleared and rehabilitated. Manila has requested almost $900 million in foreign aid to complete the job. Meanwhile, volcanologists are nervously watching the growing threat of more debris from Pinatubo. "We're concerned that Pinatubo is gather a new crater lake and that there is going to be a new flow," Mr. Rodolfo says.