Adams Glacier, the largest glacier on Mount Adams, covers the volcano’s northwest flank in Washington and runs from the summit ice cap above 12,000 feet to near 7,000 feet, feeding Adams Creek. Its form changes dramatically with elevation, from a steep icefall with seracs that makes for one of the mountain’s harder climbing routes to a broad lower ice field that splits into five tongues between moraines. Named during early mapping in 1901 after Harry Fielding Reid declined to place his own name on the map, it was first recorded as climbed in July 1945. Since 1904, it has shrunk by 68 percent, making it a clear sign of long-term environmental change.