“Two or three inches of snow, we can handle that,” Maribel Martinez-Mejia, the director of emergency preparedness for the North Central Texas Council of Governments, told me. But, she said, more than a quarter inch of ice is a challenge; her region could see about half an inch or more. That amount can add as much as 500 pounds of weight to a power line and cause an outage. “The power grid is vulnerable to ice,” Jason Shafer, a meteorologist and the chief innovation officer at PowerOutage.us, told me. “It’s hard to winterize the system,” in part because doing so is expensive. Many places don’t have the money to spend on that project, especially if ice is a rare threat. So lines snap, and trees do too—onto the lines, sometimes. One way to avoid that is to put the lines underground, but, Shafer said, “we built everything overhead in this country.”