For buildings in parts of the snow-covered U.S. West, it has become a winter where the weak do not survive. The accumulated weight of snow has crushed an old lumber mill in Oregon, the main grocery store in a small Idaho town, a sports complex in Alaska and a conference center in Colorado, among others. They have led to some injuries and at least one death, when the roof of a woman’s snow-laden porch in northern Idaho fell while she was underneath it, officials say. Authorities fear more collapses will come.