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-mili... 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.