Overview
- Hurricane-force winds in Colorado led Xcel Energy to preemptively cut power on December 17, triggering an outage at NIST’s Boulder campus.
- A downstream standby generator failure interrupted the primary signal distribution to Boulder Internet Time Service servers, even as the atomic clocks continued on battery backup.
- NIST reported UTC(NIST) deviated by roughly 4 to 4.8 microseconds, a negligible shift for most users but potentially consequential for high-precision telecommunications, aerospace, and laboratory systems.
- NIST warned sensitive users to switch to alternate time sources and weighed taking Boulder servers offline, ultimately keeping them up given typical NTP error bounds.
- Utility service was restored by December 21, with assessment, repair, and recalibration completed to remove the drift, while alternate sites and GPS common-view methods maintained continuity for many users.