High in the Rocky Mountains of Colorado and Wyoming, under thin air and bluebird skies, the Colorado River Basin is slowly replenishing its savings account. Craggy peaks become smooth walls of white, and snow piles up against conifer trunks, covering even the deepest, darkest corners of the forest in a glimmering blanket.

Snow that accumulates on the western slope of the Rockies eventually becomes water in the Colorado River. Some of it will flow as far south as Mexico, running through kitchen faucets in cities and suburbs along the way, or watering crops that keep America fed.