 By 1932, Quizapu had produced many phreatic events and one effusive eruption, but no large Plinian eruptions. This frequency of minor eruptive activity proved to be a precursor for a major eruption. On 25 January 1932, observers in Malargue saw a large black cloud over the summit. By 9 April, the volcano emitted green gas and started to "bellow like a bull". On April 10, Cerro Azul finally erupted, releasing a towering column or plume of white gas. After 10 AM, the plume turned black with ash and began to form an umbrella shape. The ash was carried by wind into Puesto El Tristan in Argentina, about 47 kilometers (29 mi) away, where beginning at 1 PM it rained down for hours. At 4 PM, coarser sandy material and some pumice lapilli began to fall.
