Based on observations during an overflight on 17 June, SERNAGEOMIN reported that ash plumes emitted from the S contact between Chaitén’s old and new lava domes rose to an altitude of 2 km (6,600 ft) a.s.l. and drifted N and NW. An explosion temporarily propelled the ash plume to an altitude of 3 km (10,000 ft) a.s.l. and steam plumes rose from several other contact points along the S edge of the lava dome. Rockfalls from the active dome continued to descend the S flank of the old dome to the caldera floor. During 18-21 June, visual observations were inhibited due to inclement weather. During 18-20 June, possible ashfall was reported in Queilén (about 70 km W) and Quellón (about 80 km WSW). Ashfall was reported in Chaitén town (10 km SW) and other areas SE, W, and E. The Alert Level remained at Red.
Based on observations of satellite imagery, SIGMET reports, and pilot observations, the Buenos Aires VAAC reported that during 18-24 June ash plumes rose to altitudes of 2.4-4.6 km (8,000-15,000 ft) a.s.l. and drifted approximately NE, E, SE, SW, and W. Thermal anomalies were identified on satellite imagery on 19 and 22 June.
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Buenos Aires Volcanic Ash Advisory Center (VAAC) – “Reports provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”