The 1991 eruption of Mount Pinatubo caused lahars: the first eruption itself killed six people, but the lahar killed more than 1500. The eye of Typhoon Yunya passed over the volcano during its eruption on June 15, 1991. The rain from the typhoon triggered the flow of volcanic ash, boulders, and water down the rivers surrounding the volcano. In Pampanga, Angeles and neighbouring cities and towns were damaged by the volcano's lahar when Sapang Balen Creek and the Abacan River became the channels for the mudflows and carried it to the heart of the city and surrounding areas.