Operation Fiery Vigil
Operation Fiery Vigil was the emergency evacuation of all non-essential military and U.S. Department of Defense civilian personnel and their dependents from Clark Air Base and U.S. Naval Base Subic Bay during the June 1991 eruption of Mount Pinatubo in the Philippines. This non-combat operation resulted in the transfer of roughly 20,000 people from Clark Air Base and U.S. Naval Base Subic Bay back to contiguous United States, by way of Cebu, Philippines. The commanding general, 13th USAF, was in command of the joint task force. Aftermath. The 1991 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. Twenty million tons of sulfur dioxide and roughly of tephra are estimated to have been ejected in total, which corresponds to a Volcanic Explosivity Index of 6. By contrast, roughly 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 , , , , , USS "Gary", , , USS "Lake Champlain", and sixteen other U.S. Navy ships of the task force including the forward-deployed, Guam-based World War II-era submarine tender . was the first ship to enter Subic Bay and provided fresh water, manufactured coffins and volcanic ash shovels to assist SRF Subic Bay and the base with recovery and rescue operations.