The Almaden Air Force Station began operations atop Mt. Umunhum on March 21, 1958. At its peak, it was an entire community for roughly 120 airmen and their families, and it had housing, a fallout shelter, a cafeteria, a commissary and recreational facilities that included a bowling alley and a basketball court.
Home to the 682nd Radar Squadron, the station was part of an extensive string of radar stations meant to protect the United States against an air raid during the Cold War.
Originally equipped with two height-finding radar towers and a "domed'' search radar, the station put its signature 85-foot-tall concrete radar tower and antenna into operation in 1962. Equipped with a colorful "sail,'' it fed data into the Semi Automatic Ground Environment (SAGE) system, which was designed by IBM. Valley residents remember that the rotating radar sometimes interfered with television transmissions -- but it gave a sense of audible protection to everyone under its umbrella.
The enemy aircraft never arrived, and satellite systems took on the duty of detecting missiles leaving Soviet silos.
With federal budgetary restrictions looming, the Almaden station closed on April 1, 1980. The property was acquired by the Midpeninsula Open Space District in 1986, and has remained off-limits to the public. After cleaning up the site, the open space district plans to level the remnants of the station. The fate of the radar tower, its most visible marker atop the 3,486-foot Mt. Umunhum, is still uncertain.