On Aug. 10, however, the West's power grid failed again. This time 4 million people lost electricity for everything from air conditioners to traffic lights, mostly in California. Alsberg says the culprit was "random multiple transmission line outages, most likely from overloaded, sagging powerlines." There was also another flashover to a tree, she adds, "but no, this is not a trend." The council is a voluntary group that promotes electricity reliability in 14 Western states plus parts of Canada and Mexico.