Global Volcanism Program | Image GVP-04249
Steam rises from of a small, hot lahar as it travels down the Río Tabacón on the NW flank of Arenal in August 1968, following a powerful explosive eruption that began on 29 July. The lahar damaged the road across the base of the volcano, about 4 km from the summit.
Photo by William Melson, 1968 (Smithsonian Institution).
This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.