Heavy Rains Trigger Lahar at Ecuador’s Reventador Volcano

Heavy rain triggered a small to moderate lahar at Ecuador’s Reventador volcano on Sunday, but the flow did not signal a rise in the volcano’s internal activity.

The flow began at about 1:20 p.m. in the Reventador ravine on the volcano’s northern flank, according to Ecuador’s Geophysical Institute of the National Polytechnic School. The institute advised people to stay away from river and ravine channels.

A lahar forms when water carries volcanic material downhill. In this case, rainfall loosened sediment and deposits that had accumulated at higher elevations, sending mud, rocks and other material through natural drainage channels.

The institute described the event as secondary because rain, rather than a new eruption or sudden change in the volcano’s internal behavior, caused the material to move. A similar small to moderate lahar occurred on Aug. 16 in the Marker ravine on the southern flank.

The warning applies particularly to communities, drivers, workers and productive activities near waterways originating on the volcano. The institute has previously cautioned that loose material on Reventador’s slopes can be remobilized by heavy rain. The volcano, which stands about 3,560 meters high, continues to show high surface activity.