Prouty Glacier occupies the northeast slopes of South Sister in Oregon’s Cascade Range on the flank of the dormant stratovolcano, spanning elevations of about 9,500 to 8,500 feet. Immediately beyond the glacier’s current edge to the northeast lies Carver Lake, which was formed by glacial action. The lake is retained by the glacier’s old terminal moraine, preserving clear evidence that the ice once extended farther than it does today.