On April 2, 1991, pilots reported seeing smoke and steam explosions emanating from Mount Pinatubo.
By June it was clear that a major volcanic eruption was imminent. Clark Air Base was completely evacuated of all but security personnel on June 10, two days before Mount Pinatubo began the summer-long series of eruptions. The first “big” eruption hit on June 12. On June 14, the base was drenched in a sea of ash and the biggest eruption followed on June 15. Tens of thousands of Filipinos fled the eruption of Mount Pinatubo, along ash-clogged roads, while the U.S. began evacuating all 20,000 dependents at Clark Air Base. 700 people died in the eruption.
On October 28, 1991, NSGA Clark AB was evacuated due to Mt. Pinatubo volcano eruption. The command was relocated and merged with NSGD Subic Bay to form NSGA Subic Bay. NSGA Subic Bay closed on May 18, 1992.
Clark Airbase was named for Major Harold M. Clark, of the U.S. Army Signal Corps. Born in Minnesota and raised in Manila, Clark was commissioned a second lieutenant of Cavalry in 1913. In 1916, he transferred to the Aviation Section of the Signal Corps, and in 1917 was rated a Junior Military Aviator. He went to Hawaii to command an air service station and was the first U.S. airman to fly in Hawaii. Clark later became an Executive Officer with the Aviation Section in Panama. On May 2, 1919, Major Clark died in a seaplane crash in the Miraflores Locks, Panama Canal Zone He was interred at Arlington National Cemetery.
On February 6, 1899, the U.S. Senate voted to annex the Philippines. In order to establish control over the central plains of Luzon, the first permanent U.S. Army presence was in the Talizundoc area of Angeles City. In 1902, the U.S. Army studied relocating their post from Angeles City to a fertile plain, on what was later Clark Air Base, which had better grass for their horses.
President Roosevelt signed an executive order on September 1, 1903, establishing 7700 acres as Fort Stotsenberg, with Camp Wallace (later Wallace Air Station) and Camp John Hay (later John Hay Air Base) being established in November, 1903.
The U.S. Army’s Fort Stotsenberg cavalry post was centered on what was later to become Clark’s parade ground in modern years. Fort Stotsenberg was commissioned on September 16, 1906. In 1908, an executive order expanded Fort Stotsenberg from 7700 to 156,204 acres, making the future Clark Airbase the largest overseas U.S. military base in the world. Most of that acreage was unoccupied fields and jungle.
On December 8, 1941, the Japanese launched an attack on Clark Field, destroying dozens of aircraft. Clark was evacuated on December 24, 1941. On January 31, 1945, American forces regained possession of Clark Field after three years of Japanese control. However, a few Japanese soldiers still held tough in the nearby mountains, and sometimes sneaked onto the base at night to sabotage American planes.
Japan surrendered in 1945, ending World War II. In January, 1946, the 13th Air Force transferred to Clark Field. During the brief period between May, 1946 and August, 1947, the 13th AF was stationed at Fort William McKinley, on Luzon.
The U.S. and Philippines signed the Military Bases Agreement on March 14, 1947; which guaranteed American possession of U.S. bases in the Philippines for 99 years. In May, 1949 the facilities at Fort Stotsenberg and Clark Field were transferred to the U.S. Air Force, and from then on, the entire base became known as Clark Air (Force) Base. In March, 1964, Clark entered the Vietnam War effort, as KC-135 tankers staged from Clark and refueled fighters enroute to Laos. In August 1968, late-night attacks against American servicemen led to both Clark and Angeles City being placed on curfew. This was at a time when anti-American sentiment was at a peak. In 1972, President Ferdinand Marcos declared martial law, which also acted to suspend elections. Martial law remained in place until 1981.
Clark Air Base, a huge logistical hub that could handle any aircraft in the U.S. inventory, possessed immense parking space, petroleum storage capacities (approximately comparable to those of Kennedy International Airport in New York City), 34 ammunition igloos, and superlative communication links. Aviators of all U.S. Services sharpened their skills under simulated combat conditions at Clark’s Crow Valley gunnery range. The communications facility located on Clark AB included an operations building located in the center of an AN/FLR-9 Circularly Disposed Antenna Array (CDAA), also known as a Wullenweber antenna array.
In 1975, Clark Airbase served as a staging area for Vietnamese fleeing the North Vietnamese invasion. The first planeload, consisting of orphans, arrived on April 5.
As many as 2,000 refugees at a time were housed in a tent city in the Bamboo Bowl during April and May, 1975. A total of 30,082 refugees and 1,565 orphans were processed through Clark AB.
On the evening of May 21, 1977, a mild magnitude 5.7 earthquake hit just northeast of Clark Airbase, and was felt by many. This was a harbinger of things to come for Clark Airbase. On January 7, 1979, a revised 1947 Military Bases Agreement was ratified and executed at Clark Airbase on February 16, 1979 to transfer command and security of Clark Airbase, and other American bases, to the Philippine government. The size of the Clark Airbase reservation was reduced from 156,204 acres to 131,000 acres, with the base itself remaining at 9155 acres. On March 31, 1980 a magnitude 6.3 earthquake hit about 80 miles northeast of Clark, but was distinctly felt at the base. On the evening of April 23, 1985, a magnitude 6.3 earthquake hit just northeast of Clark.
On August 21, 1983 Ninoy Aquino, one of President Marcos’ political opponents, returned from ten years of exile and was shot on his arrival in Manila, precipitating a gradual collapse of the Marcos administration and the economy. On the evening of April 23, 1985 a magnitude 6.3 earthquake hit just northeast of Clark. On February 25, 1986, after massive outcry over a rigged election, President Marcos is forced out of office, and exiled from the Philippines. On December 29, 1986, a mild magnitude 6.0 earthquake struck along the coast west of Clark. On April 25, 1987, a strong earthquake, at magnitude 6.5, hit just north of Clark. On July 16, 1990 Clark’s worst earthquake occurred. It registered magnitude 7.6 and was centered about 80 miles northeast of the base. Baguio was devastated, with over 2000 killed and a million homeless.
The Philippine Senate rejected an extension of the Military Bases Agreement, and it expired on September 16, 1991. The U.S. Air Force formally transferred Clark Airbase in its entirety to the Philippines on November 26, 1991 ending its century-long presence in the region. On October 1, 1992, the U.S. Navy withdrew from Subic Bay Naval Base. Subic Bay was the last of the U.S. Military Bases in the Philippines, which were handed over to the Philippine Government. The U.S. presence in the Philippines ended.
In 1995, following years of neglect, cleanup and removal of volcanic ash deposits began at the former Clark Airbase. The base re-emerged as Diosdado Macapagal International Airport (Clark International Airport) and Clark Special Economic Zone (CSEZ). The airfield infrastructure was improved to make it one of the most modern in Asia, and a second parallel runway was built. The former base is now home to a golf resort, a number of industrial buildings, landmarks, and retail establishments. It also hosts the annual Balikatan exercises between the U.S. and Philippines Armed Forces.
In 1997, the AN/FLR-9 at the former Clark Airbase in the Philippines was converted into a 35,000-seat fabric-covered amphitheater.