Chapter 23 · Prolonged collapse
23.1 Realistic scenarios
You do not need to prepare for every scenario separately. They all end in the same place: no grid power for a long time, with cascading effects. What changes is the cause, the advance warning, and how long it lasts.
| Scenario | Advance warning | Possible duration | What we know |
|---|---|---|---|
| Catastrophic hurricane (coast; inland areas receive rain, wind, and evacuees) | Days | Days to months in the affected area | After Maria, Puerto Rico took 11 months to restore power to the last sector. After Hurricane Beryl (2024), more than 2.7 million customers lost power in the middle of July heat. |
| Regional grid failure (extreme cold or heat, demand greater than generation) | Hours to days (grid operator warnings, chapter 9) | Hours to weeks | In February 2021, a regional U.S. power grid came within about 4 minutes and 37 seconds of a collapse that, according to its own officials, could have left an entire region without power for weeks or more. |
| Geomagnetic storm (solar activity) | Usually hours to 1–3 days (NOAA Space Weather Prediction Center alerts) | Hours, in most cases; an extreme event could damage transformers that are hard to replace | In March 1989, a storm left about 6 million people in Quebec without power for about 9 hours. The G5 storm of May 2024 did not cause major failures in the North American grid. |
| Electromagnetic pulse (EMP) from a high-altitude nuclear detonation | None | Very uncertain | Low-probability, high-uncertainty scenario. See 23.2. |
| Cyberattack or physical attack on the grid | None | Hours to weeks, depending on the damage | The effects for you would be the same as in a grid failure. |
Why some outages last months
A grid can be reconnected in days if the equipment is intact. What lengthens a blackout is physical damage to large equipment. Large power transformers are built to order: a 2024 report by the National Infrastructure Advisory Council (NIAC, published by CISA) reports lead times of 80 to 210 weeks, with an average of about 120 weeks in 2024. That is why a hurricane that destroys power lines, or an extreme solar storm that damages transformers, can turn a blackout into a months-long problem in some areas.
