Like rust slowly consuming the body of a car, drought has spread upstream on the Colorado River. The river’s Upper Basin – generally north of Lake Powell – has been largely insulated from the 19-year drought afflicting the giant watershed, thanks to the region’s relatively small water demand and heavy snows that bury Colorado’s 14,000ft peaks each winter. But this year, there was no salvation in the snowpack. Several major Colorado River tributaries – the Dolores, San Juan and Gunnison rivers – saw record-low snowpack this winter.