Pinatuboâs 1991 eruption served as shattering finale to US basing in Philippines by Ash covers the ground and cars at Clark Air Base, Philippines, a day after the eruption of Mount Pinatubo on June 15, 1991. (U.S. Geological Survey) Ash, smoke and mayhem descended onto Clark Air Base when nearby Mount Pinatubo erupted three decades ago in the Philippines. In the hours after the eruption on June 15, 1991, Susan Kreifels, Stars and Stripesâ Philippines bureau chief who lived on the base, was stuck in a snarl of traffic on her way to Manila. Her driver inched through the dusk cr...