A power outage on Wednesday in Boulder, Colorado, caused a 4.8 microsecond deviation in the U.S. official time standard, NIST UTC. The incident occurred at the National Institute of Standards and Technology (NIST) laboratory, which maintains the atomic clocks responsible for calculating the nation's time.
The disruption resulted from a windstorm that led to a power failure. Subsequently, a backup generator at the facility also failed, affecting the system's ability to maintain precise timekeeping.
Time Deviation Details
NIST spokesperson Rebecca Jacobson confirmed that NIST UTC became 4.8 microseconds slower than its intended value. For context, a typical human blink lasts approximately 350,000 microseconds.
Since 2007, the U.S. official time standard, known as NIST UTC, has been determined by the Commerce Secretary and the U.S. Navy. This standard operates in conjunction with, but is distinct from, the global Coordinated Universal Time (UTC), to which the U.S. contributes measurements.
System Interruption Cause
The NIST facility computes the national time standard by averaging readings from 16 atomic clocks. These clocks, which include hydrogen masers and cesium beam clocks, utilize atomic resonant frequencies for their high accuracy. Although the atomic clocks continued functioning on their battery backup systems during the outage, the connection between some clocks and NIST's measurement and distribution systems was interrupted.
Critical operations staff on site were able to restore backup power by activating a reserve diesel generator.
Potential Impact
Jeff Sherman, a NIST supervisory research physicist, stated that the significance of the 4.8 microsecond drift is dependent on the user. While the general public would likely remain unaffected, applications requiring high-precision time synchronization, such as critical infrastructure, telecommunications, and GPS signals, could potentially experience consequences. NIST communicated the disruption to its high-end users, who have access to alternative time-keeping networks.
By Saturday evening, power had been restored to the NIST facility in Boulder. Crews are currently evaluating damage and working to correct the 4.8 microsecond deviation.