The problem had been brewing for nearly a decade, intelligence sources had warned, as the National Security Agency vacuumed up more and more surveillance information into computer systems at its Fort Meade, Maryland, headquarters: There just wasn’t enough power coming through the local electric grid to support the rate at which the agency was hoarding other people’s communications.

“If there’s a major power failure out there, any backup systems would be inadequate to power the whole facility,” a former NSA manager told the Baltimore Sun in August 2006.

“It’s obviously worrisome, particularly on days like today.”

It turns out that manager, and other sources quoted in the Sun piece, were even more correct than was publicly known at the time: The NSA had, just the prior month, already experienced a major power outage and been forced for the first time to switch over its most critical monitoring — its nerve center, the National Security Operations Center — to a backup facility in Augusta, Georgia, according to an internal report classified “secret.” The culprit: hot weather and electric company problems generating sufficient power, according to an article posted on the internal agency news site known as SIDtoday.