Based on SIGMET reports, the Buenos Aires VAAC reported that during 22-24 May ash plumes from Ubinas rose to altitudes of 4.9-7.9 km (16,000 and 26,000 ft) a.s.l. and drifted S, E, NE, and SE. On 26 May, a pilot reported that a plume rose to an altitude of km (18,000 ft) a.s.l. and drifted SSE. The plume was also identified on satellite imagery.
Source: 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.”