Only if the rooms that coordinate recovery are built for it. A long, multi-region outage changes what walls, fuel, water, communications and staffing a continuity facility needs, and those decisions are made at design time.
The Electric Infrastructure Security Council defines a Black Sky hazard as a catastrophic event that severely disrupts the normal functioning of critical infrastructure in multiple regions for long durations. The definition matters because of what it removes: mutual aid from the next county, fuel deliveries on the normal schedule, and the assumption that the grid comes back in a few days.
Recent events set the floor
Winter Storm Uri, in February 2021, was not a Black Sky event, and it still showed how quickly ordinary assumptions break. FERC and NERC reported that more than 4.5 million people in Texas lost power, some for as long as four days, and that ERCOT ordered 20,000 MW of rolling blackouts, the largest manually controlled load-shedding event in U.S. history. The Texas Department of State Health Services confirmed 246 storm-related deaths, most from hypothermia.
A continuity facility sized for Uri would have needed to run through four days of grid loss in extreme cold, with fuel logistics disrupted and staff unable to travel. A Black Sky assumption stretches that to weeks.
How long is long enough?
CISA's Resilient Power Best Practices give critical sites a practical scale. Its resilience levels run from about three days of expendable supplies such as fuel at Level 1, through seven days and about 30 days, to no unplanned downtime at Level 4. The document also asks sites to write their threats and vulnerabilities into the physical security plan and to exercise them with local law enforcement.
Regulations rarely set a number. For hospitals, the CMS emergency preparedness rule requires generators to be located and maintained according to NFPA 99, NFPA 101 and NFPA 110, and requires hospitals with on-site fuel to plan how they will keep emergency power running during an emergency unless they evacuate. It does not specify hours of fuel, despite claims that it does. FEMA's P-1019 guidance on emergency power for critical facilities likewise asks owners to plan for how long they can run before fuel, oil and filters need replacing, rather than prescribing a duration.
That leaves the duration as an owner's decision, and it should be an explicit one.
What a thirty-day assumption changes
- Fuel and water. Storage, treatment and a resupply plan that does not depend on the normal supply chain.
- The envelope. Walls and roofs that protect the coordinating room from the hazard and from people seeking shelter, fuel or equipment when order is strained.
- Communications. Radio and satellite paths that do not share a single tower, trench or power source.
- People. Space to sleep, eat and rotate shifts, because a room nobody can staff for weeks is not a continuity facility.
- Repair. Spare parts, tools and the trained people to use them on site.
For the life-safety part of the problem, FEMA P-361 sets design guidance for community and residential safe rooms against tornadoes and hurricanes. It is a useful reference for the structural side of shelter even where wind is not the primary hazard.
Pick the duration first. Three days and thirty days produce different buildings, and the difference is set in the design, not improvised during the event. Deciding which rooms deserve it is covered in How Does a Community Find the Node That Must Not Fail?
Sources
- Electric Infrastructure Security Council, Black Sky
- FERC, Final Report on February 2021 Freeze (Nov. 16, 2021)
- Texas DSHS, February 2021 Winter Storm-Related Deaths (Dec. 31, 2021)
- CISA, Resilient Power Best Practices fact sheet
- 42 CFR 482.15, Condition of participation: Emergency preparedness
- FEMA P-1019, Emergency Power Systems for Critical Facilities
- FEMA P-361, Safe Rooms for Tornadoes and Hurricanes (4th ed.) via PNNL
Cite this article: Authentic Intelligence Research, “Can a Community Be Ready for a Black Sky Event?” Authentic Intelligence, September 30, 2026, https://authenticint.com/articles/black-sky-readiness-starts-with-the-structure.html.