Rocky Mountain News: Vail and Colorado’s other ski areas will have to carve runs higher up the mountains and triple their snowmaking if they are to co-exist with global warming over the coming decades, a new study says. That extra snowmaking will require a lot more water at a time when it is very expensive to buy senior water rights, says the study presented today to the American Geophysical Union conference in San Francisco. And it would have to come from a distance away, because any diversion close by …