The shutoffs, known as “public safety power shutoffs,” are enacted so that during scorching, windy weather, power lines won’t inadvertently spark a blaze. Those moves are deeply unpopular, but Xcel says they were necessary. Behind the scenes, Xcel executives were heeding advice from a team of weather scientists as they decided where and when to cut the flow of power. It “all starts with meteorology,” says Paul McGregor, the company’s vice president of wildfire risk management.