Operation Fiery Vigil - Aftermath

Aftermath

The 1991 Plinian/Ultra-Plinian eruption of Mount Pinatubo was the second largest terrestrial eruption of the 20th century (surpassed only by the 1912 eruption of Novarupta), and the largest eruption in living memory. The eruption produced high-speed pyroclastic flows, giant lahars, and a cloud of volcanic ash hundreds of miles across. 20 million tons of sulfur dioxide and roughly 11 cubic kilometers (2.6 cu mi) of tephra are estimated to have been ejected in total, which corresponds to a Volcanic Explosivity Index (VEI) of 6. By contrast, roughly 4 km3 of material was ejected in the 1980 eruption of Mount St. Helens; this corresponds to a VEI of 5.

Very few of the estimated 20,000 who left the base ever returned. The vast majority were evacuated to Andersen Air Force Base, Guam and processed for return to the continental United States. This figure includes approximately 5,000 who were evacuated to Cebu City on the USS Midway (CV-41), USS Abraham Lincoln (CVN-72), USS Peleliu (LHA-5), and twenty other U.S. Navy ships of the task force.

• 22 June 1991: a team of 11 engineers and utility systems specialists from Headquarters Pacific Air Forces (PACAF) and the 554th Rapid Engineer Deployable Heavy Operational Repair Squadron Engineers (RED HORSE) arrived at Clark Air Base to assess the damage caused by Mount Pinatubo to determine the fate of the base.
• 12 July 1991, the United States Secretary of the Air Force announced that the U.S. Air Force would leave the Philippines no later than 16 September 1992.
• 4 September 1991: a lahar, 20 feet (6.1 m) to 40 feet (12 m) high and almost 200 feet (61 m) wide, smashed along the southern boundary of Clark Air Base, sweeping away a security policeman who was subsequently rescued.
• 5 November 1991: the Secretary of the Air Force visited Clark Air Base and paid tribute to the "Ash Warriors", the personnel who had remained throughout the volcanic activity and cleanup.
• 26 November 1991: the American flag was lowered for the last time by the Ash Warriors, and Clark Air Base was turned over to the government of the Philippines, ending over 90 years of US presence at the base.