In 1963 Mt. Agung, Indonesia, showed unrest for several months. During this period, two medium-sized eruptions injected SO₂ into the stratosphere. Recent volcanic emission datasets include only one large eruption phase. Therefore, we compared model experiments, with (a) one larger eruption and (b) two eruptions as observed. The evolution of the volcanic cloud differs significantly between the two experiments. Both climatic eruptions should be taken into account.