On 22nd April Calbuco volcano, Chile, erupted for the first time since 1972 with very little warning. Plumes of volcanic ash reached heights of 16 km on the 22nd and up to 17 km in a second, longer eruption that began in the early hours of 23rd April.
Several thousand people were evacuated from villages closest to Calbuco , and ash fell over an area extending from the west coast of Chile to the east coast of Argentina, and grounded air traffic in Chile, Uruguay and Argentina.
COMET scientists have been using satellite data to analyse the event, in terms of both the emissions and changes to the shape of the volcano itself. You can read more about the event here.