The truth is, solar flares as large as the one that caused the 1859 Carrington Event happen fairly regularly. Since we started monitoring the Sun’s solar cycle, we’ve gotten lucky on a number of occasions — CMEs that would have hit us even harder than 1859 have merely glanced us due to a non-ideal trajectory. Meanwhile, the United States’ grid is more vulnerable to such events than ever before — our transformer grid is, on average, nearly 40 years old, high-voltage power lines are carrying far more energy than they used to on a day-to-day basis, and there’s virtually no way to quickly repair the damage such a storm would cause.