Based on a pilot observation and a SIGMET notice, the Washington VAAC reported that on 26 May a diffuse ash plume from Reventador rose to an altitude of 6.4 km (21,000 ft) a.s.l. and drifted SW. Thermal anomalies were intermittently seen on satellite imagery. Gas plumes with some possible ash were noted later that day.

Geological Summary. Volcán El Reventador is the most frequently active of a chain of Ecuadorian volcanoes in the Cordillera Real, well east of the principal volcanic axis. The forested, dominantly andesitic stratovolcano has 4-km-wide avalanche scarp open to the E formed by edifice collapse. A young, unvegetated, cone rises from the amphitheater floor to a height comparable to the rim. It has been the source of numerous lava flows as well as explosive eruptions visible from Quito, about 90 km ESE. Frequent lahars in this region of heavy rainfall have left extensive deposits on the scarp slope. The largest recorded eruption took place in 2002, producing a 17-km-high eruption column, pyroclastic flows that traveled up to 8 km, and lava flows from summit and flank vents.

Source: Washington Volcanic Ash Advisory Center (VAAC)