Foss Glacier lies on the northeast slope of Mount Hinman in Washington’s Alpine Lakes Wilderness within Snoqualmie National Forest, high in the central Cascades amid rugged alpine terrain shaped by ice and steep ridgelines. It is significant for showing recent glacier change in this part of Washington: between 1950 and 2005, it retreated almost 500 meters, or about 1,600 feet. A ridge separates it from Hinman Glacier to the west, which has nearly vanished, underscoring the broader decline of mountain ice in the surrounding landscape.