In 2008, NORAD changed its Cheyenne Mount Complex to a backup command
center. NORAD's day-to-day early warning mission was moved to Peterson
Air Force Base. The Cheyeene Mount Complex was kept ready as a 'warm
backup' and skeleton maintenance and training crews.
In late February 2020, NORAD split its operation staff into two watch
centers and re-activated the Cheyenne Mountain Complex. Crews do not
physically interact with the other watch crews to minimize an infection
impacting both command centers. When off-duty, they stay in separate
quarters in distant areas on Peterson AFB.
https://www.stripes.com/news/air-force/to-protect-no-fail-mission-norad-military-personnel-move-into-mountain-bunker-1.628497
Of course, not everyone has a mountain lair on standby. I've also heard
some electric grid operators made similar staffing changes. The ISO
operation staff is split into seperate crews, which physically isolate on
and off-duty during their 7 or 14-day watches.
