Map of the United States color coded to indicate extreme snow melt. Josh Welty The map shows the greatest amount of snow loss over a two day period across the United States within a 30-year window. The largest snow loss, indicated by green and blue, occurs in the mountains of the western United States. Units are millimeters of snow mass lost per two days. Only pixels, which equate to 2.5 square miles each, with extreme snow loss (exceeding 50 mm per two days) are included.