Steam rises from the summit crater of Nevado del Ruiz volcano on December 10, 1985. Pyroclastic-surge and -fall deposits from the November 13 eruption extend from the crater. Glaciers on the upper-NE-flank headwall of the Azufrado valley in the foreground were scoured by pyroclastic surges.

Photo by Tom Pierson, 1985 (U.S. Geological Survey).

Ruiz, Nevado del