Global Volcanism Program | Image GVP-03011
Volcanic activity at glacially eroded Mount Jefferson, Oregon's second highest peak, ended during the Pleistocene. However, cinder cones south of the volcano have been active as recently as about a thousand years ago. The extensive Whitewater Glacier in the foreground has eroded deeply into the volcano and blankets the east flank of Jefferson.
Photo by Willie Scott, 1981 (U.S. Geological Survey).