Small phreatic explosions on April 2, 1991, ended more than 400 years of quiescence at Mount Pinatubo. A joint Philippine-United States team worked quickly to understand the unrest and the eruptive history of Pinatubo, and to warn those at risk. These warnings led to the evacuation of at least 58,000 people prior to the volcano's climactic eruption on June 15. Although 320 people died in that eruption, mostly due to collapse of ash-covered roofs, the evacuations and other precautions averted a much greater loss of life and property.